A hematocrit test (Hct) measures how much of your blood consists of red blood cells. Capillary hematocrit refers specifically to the measurement obtained using a small capillary tube — a method also called the microhematocrit technique, which requires a smaller blood sample and less time for the testing procedure. The result is expressed as a percentage, representing how much of your total blood volume is made up of red blood cells.

Blood is made of red blood cells, white blood cells, platelets, and plasma (the fluid part). Having a healthy number of red blood cells is important because they carry oxygen throughout your body.

Why is hematocrit important?

Hematocrit is often used as an indicator of the oxygen-carrying capacity of blood. It can also be used as an indicator of the health of the bone marrow where red blood cells are produced.

Hematocrit levels that are too high or too low can indicate a blood disorder, dehydration, or other medical conditions. An abnormally low hematocrit may suggest anemia, a decrease in the total amount of red blood cells, while an abnormally high hematocrit is called polycythemia.

How can I better understand my hematocrit levels?

Higher than normal hematocrit may indicate polycythemia or erythrocytosis. Causes of a high hematocrit include dehydration, low availability of oxygen (such as from smoking, high altitude, or pulmonary fibrosis).

Lower than normal hematocrit may indicate anemia or nutritional deficiencies. A low hematocrit with a low mean corpuscular volume (MCV) and a high red cell distribution width (RDW) suggests a chronic iron-deficient anemia resulting in abnormal hemoglobin synthesis. Decreased hematocrit levels could also indicate life-threatening diseases such as leukemia. Further evaluation, including a complete blood count (CBC) and medical history assessment, may be necessary to determine the underlying cause.

How can I maintain optimal hematocrit levels?

Maintaining balanced hematocrit levels involves the following steps:

Dietary Changes: Iron-rich foods work better when paired with vitamin C sources. Your body absorbs less iron if you consume caffeine and calcium with meals. Heme iron sources such as red meat, liver, poultry, fish, and seafood provide the most usable form of iron. Non-heme iron sources like beans, lentils, spinach, tofu, and fortified cereals provide plant-based iron. Vitamin B12, found in animal and dairy products, is essential for red blood cell production. Those following a vegetarian or vegan diet may need to take vitamin B12 supplements. Consuming a source of Vitamin C, like citrus fruits, bell peppers, or strawberries, alongside non-heme iron foods such as spinach or beans can significantly improve iron uptake.

Lifestyle Changes: Stay hydrated by drinking 8–12 glasses of water per day, engage in moderate exercise like brisk walking or light cycling, and avoid smoking, as it can negatively impact circulation and overall blood health. Engaging in intense physical activity, particularly endurance exercise, can stimulate the body to produce more red blood cells over time, helping improve oxygen delivery to working muscles. Stress takes a toll on blood health, as the body releases hormones that affect how blood flows and delivers oxygen, so managing stress is important for maintaining healthy hematocrit levels.

Supplementation: Supplements containing iron or B vitamins should only be taken after a confirmed deficiency is diagnosed by a doctor, as iron supplements can cause side effects like constipation, and excessive intake without a deficiency can lead to iron overload. In some cases, your physician may also recommend folate (vitamin B9) to support red blood cell production.

Where can I learn more?

• PubMed – Hematocrit
• Cleveland Clinic – Hematocrit Test
• NCBI Bookshelf – Hemoglobin and Hematocrit

DISCLAIMER: IF YOU ARE CONCERNED WITH ANY OF YOUR RESULTS, PLEASE CONSULT WITH YOUR PHYSICIAN.

Heart & Metabolic Age is a simplified, age-like estimate of your cardiometabolic health, based on two powerful signals from your bloodwork:

1. Atherogenic particle burden (how many “plaque-forming” cholesterol particles you carry)
2. Insulin sensitivity (how efficiently your body handles energy and blood fats)

It’s designed to be easy to understand, easy to track over time, and tightly focused on the health domains that drive long-term cardiovascular and metabolic risk.

The Heart & Metabolic Phenotype

To give a clearer picture than a single number alone, we first place you into a 2×2 phenotype map based on two inputs:

1) Lipid Metabolism (ApoB)

ApoB reflects the number of atherogenic (“plaque-building”) particles in your blood (including LDL and other ApoB-containing particles). In general:

• Lower ApoB = fewer atherogenic particles
• Higher ApoB = more atherogenic particles

2) Insulin Sensitivity (Triglycerides/HDL-C Ratio)

The Triglycerides-to-HDL-C ratio (Trig/HDL-C) captures two hallmarks of reduced insulin sensitivity: higher triglycerides and lower HDL-C. A lower ratio suggests better metabolic efficiency.

In general:

• Lower Trig/HDL-C = better insulin sensitivity signal
• Higher Trig/HDL-C = more insulin-resistance–associated pattern

What the 4 phenotypes mean

Your position on the map reflects one of four patterns:

• Optimal: Both ApoB and insulin sensitivity look favorable
• Lipid regulated, insulin resistant: ApoB looks favorable, but the Trig/HDL-C pattern suggests reduced insulin sensitivity
• Lipid dysregulated, insulin sensitive: insulin sensitivity looks favorable, but ApoB suggests elevated atherogenic particle burden
• Lipid dysregulated, insulin resistant: both signals suggest higher heart and metabolic risk

This map helps you understand whether your focus should be on lipids, metabolic health, or both.

How Heart & Metabolic Age is Calculated

After placing you on the 2×2 phenotype map, we translate your ApoB and Trig/HDL-C pattern into a single Heart & Metabolic score, then translate that score into an age-like number relative to your chronological age.

Younger Heart & Metabolic Age reflects a more favorable cardiometabolic profile—your markers look like those typically seen in lower-risk, younger individuals.

Older Heart & Metabolic Age suggests more room for improvement in the factors that drive cardiovascular and metabolic risk.

How to Interpret Your Heart & Metabolic Age

• Lower than your chronological age: Your ApoB and insulin-sensitivity pattern look more like what’s typical in lower-risk, younger cardiometabolic profiles.
• Higher than your chronological age: Your markers look more like patterns commonly associated with higher cardiometabolic risk, which can be a useful prompt to focus on improvements.
• Close to your chronological age: Your profile is broadly similar to others in your age range.

Just like with any health score, the most useful insight often comes from trends over time, especially if your collection conditions are consistent.

Why This Matters

Cardiometabolic health isn’t just one factor among many, it’s foundational. Atherosclerosis and insulin resistance are among the strongest predictors of long-term disease risk, and both are influenced by modifiable factors like diet, exercise, sleep, and stress.

Heart & Metabolic Age distills these complex dynamics into a single, trackable number. Instead of interpreting multiple markers in isolation, you get a clear summary of where you stand and whether you’re trending in the right direction.

Important Notes and Limitations

• This is not a diagnosis and does not replace medical care.
• Triglycerides (and therefore Trig/HDL-C) can shift with recent meals, alcohol, illness, sleep disruption, and recent intense exercise. For the cleanest comparisons, test under similar conditions each time.
• Medications and supplements (especially lipid- and glucose-related therapies) can meaningfully change these markers—often in a positive direction. This is expected and reflects real improvement.

You’re 45 years old, but is your body? That’s the question biological age tries to answer.

Your chronological age is simply how many years you’ve been alive. Your biological age looks deeper, examining patterns across your blood biomarkers to estimate whether your body more closely resembles someone younger, older, or right around your actual age.

Think of it as a health fingerprint translated into a single, trackable number.

How to Interpret Your Result

• Lower biological age: Your overall biomarker pattern looks more similar to people who are chronologically younger.
• Higher biological age: Your overall biomarker pattern looks more similar to people who are chronologically older. This can be a useful prompt to focus on areas that may be holding your health back.
• Similar to your chronological age: Your biomarker pattern is broadly similar to others in your age range, which is common.

A helpful way to think about this: biological age is a summary signal, not a diagnosis. It reflects the combined “shape” of your biomarker profile, not any single result.

Why It Matters

Biological age can help you:

• See the bigger picture across multiple body systems (metabolic, cardiovascular, inflammation, hormones, and more).
• Track trends over time, especially when you test consistently.
• Identify areas to prioritize when paired with your biomarker insights and action plan.

Here’s what makes biological age especially useful: because biomarkers respond to lifestyle, sleep, stress, nutrition, and medical care, your biological age can change. Unlike your chronological age, this number isn’t fixed.

How Is Biological Age Calculated?

There is no single lab test that directly measures “true” biological age, so models like ours learn how biomarker patterns typically vary with age across large populations, then compare your results to those patterns.

At a high level, our approach works like this:

• Training data: We trained our model using a combination of large public health datasets and internal data.
• How your score is generated: When you get results, the model compares your biomarker pattern to the patterns it learned and estimates the age your profile most closely resembles.

Biological age is calculated using a subset of available biomarkers (at least ~50% required). These include: 

Males: Hemoglobin A1C, Vitamin D (25-OH Vitamin D), ALT (Alanine Aminotransferase), Albumin, Apolipoprotein A1 (ApoA1), Apolipoprotein B (ApoB), AST (Aspartate Aminotransferase), Blood Urea Nitrogen (BUN), Calcium, Total Cholesterol, Cortisol, Creatinine, DHEA-S (Dehydroepiandrosterone Sulfate), Ferritin (iron storage), Follicle-Stimulating Hormone (FSH), HDL Cholesterol, High-Sensitivity C-Reactive Protein, Homocysteine, Iron, LDL Cholesterol, Luteinizing Hormone (LH), Prostate-Specific Antigen (PSA), Thyroid-Stimulating Hormone (TSH), Total Bilirubin, Total Protein, Triglycerides

Females: Hemoglobin A1C, Vitamin D (25-OH Vitamin D), ALT (Alanine Aminotransferase), Albumin, Apolipoprotein A1 (ApoA1), Apolipoprotein B (ApoB), AST (Aspartate Aminotransferase), Blood Urea Nitrogen (BUN), Calcium, Total Cholesterol, Cortisol, Creatinine, Ferritin (iron storage), Follicle-Stimulating Hormone (FSH), HDL Cholesterol, High-Sensitivity C-Reactive Protein, Homocysteine, Iron, LDL Cholesterol, Luteinizing Hormone (LH), Thyroid-Stimulating Hormone (TSH), Total Bilirubin, Total Protein, Triglycerides, Estradiol (Sensitive)

How Accurate Is It?

Biological age is an estimate. It is designed to be directionally meaningful and consistent over time, especially when you retest under similar conditions.

Short-term factors (illness, major sleep disruption, inflammation, medication changes, recent supplementation, training load, etc.) can temporarily shift biomarkers and influence the score. Some biomarkers can move in ways that are “health-positive” but still correlate with age trends in population data (for example, supplementation effects), which can sometimes affect the estimate.

Why Your Biological Age May Change Over Time

It’s normal for biological age to shift between tests because your biomarkers change with lifestyle, recovery, stress, and health status. Normal biological variation and lab variation exist, and the model may be updated over time as we expand training data and improve performance.

For interpretation, it’s best to focus on your trend over multiple tests, which biomarkers are driving the change, and whether changes match how you feel.

Biological Age vs. Heart & Metabolic Age

If you’ve also completed a Heart & Metabolic panel, you’ll see a second age estimate. Heart & Metabolic Age is a structured score translated into an age-like number based on the SiPhox Heart and Metabolic phenotype.

Biological Age uses a broader set of biomarkers and a machine learning approach trained on population patterns across age and sex. It is intended to reflect a more general “whole-body” biomarker aging signal rather than one specific domain.

Both are useful. Heart & Metabolic Age tells you how your cardiovascular system is holding up. Biological Age gives you a wider lens on overall aging. If you have access to both, consider them complementary views of your health.

Important Notes

• Biological age is not a medical diagnosis and should not be used alone to diagnose or treat any condition.
• It does not capture every factor that influences aging (genetics, imaging findings, fitness, body composition, sleep quality, medical history, and more).

This guide breaks down the major protein types, how they work in your body, and which formats best match your lifestyle and goals.

For a deeper look at why protein matters and how supplementation supports muscle, metabolism, and healthy aging, see our companion guide: Protein Supplements: What They Are and Why They Matter. 

Protein Quality: What Makes One “Better” Than Another

Not all proteins stimulate muscle growth equally. Three factors matter most:

Essential Amino Acid (EAA) content: These cannot be produced by the body and must come from food. Proteins rich in EAAs produce a stronger muscle-building response.

Leucine content: Leucine is the amino acid that “flips the switch” on muscle protein synthesis (MPS). Higher leucine means a faster, stronger anabolic signal. Whey is the richest common source.

Digestibility and Bioavailability: How much of the protein your body actually absorbs and uses matters. Scientists measure this with a score called DIAAS, where higher is better.

Comparing Protein Types

Whey Protein (Isolate, Concentrate, Hydrolysate)

Best for: post-workout recovery, muscle building, older adults, high-leucine needs

Whey is the most researched protein supplement, with decades of evidence supporting its effectiveness. It digests quickly, creates a rapid rise in blood amino acids, and is exceptionally high in leucine.

Whey Protein Isolate (WPI)

• The most refined form with ≥ 90% protein
• Low in lactose
• Fastest absorption, allowing for a large amino acid spike
• Extremely high leucine (AARR ~2.57)
• Excellent for post-workout or morning use

Whey Protein Concentrate (WPC)

• Less processed, can contain 25–89% protein
• Contains some beneficial milk peptides
• More affordable but less refined and includes more lactose and fat

Whey Hydrolysate (WPH)

• Pre-digested for even faster absorption
• Shown to stimulate MPS more than casein or soy
• Typically higher-cost

Casein Protein

Best for: overnight recovery, sustained satiety, long fasting windows

• Slow-digesting: releases amino acids for 6+ hours
• Ideal before sleep or during long gaps between meals
• Improves nitrogen retention
• Supports long-term muscle maintenance and reduces breakdown overnight.

Plant Proteins (Soy, Pea, Rice, Blends)

Best for: vegans, vegetarians, dairy-free diets, those with dairy allergies

Plant proteins vary widely in quality. None match whey for leucine content or digestibility, but they’re effective options for those avoiding animal products.

Soy Protein Isolate (SPI)

• The most complete plant protein
• DIAAS ~0.90
• Well researched and effective but produces lower MPS response vs whey at equal doses

Pea Protein

• DIAAS ~0.82
• Popular with dairy-free users
• Good amino acid profile but typically low in methionine

Rice Protein

• DIAAS ~0.37
• Incomplete on its own (low in lysine)
• Rarely used alone

Plant Blends

• Combined sources ( pea + rice + other) creates a more complete amino acid profile. This is the best approach for plant-based users.
• Still produce 30–40% lower circulating amino acids compared to whey
• Best used when avoiding animal proteins, not for maximizing MPS

Novel & Specialty Proteins

Collagen

Collagen has legitimate benefits: research supports its use for skin hydration, joint comfort, and gut health. However, it’s not a complete protein and lacks the amino acids needed to effectively stimulate muscle growth. If your goal is building or maintaining muscle, collagen shouldn’t be your primary protein source. Think of it as a complement, not a replacement.

Egg Protein

• Complete, highly digestible, and has a long history of use
• Less modern research compared to whey, but the amino acid profile is strong
• Good alternative for dairy-sensitive individuals who want high-quality animal protein

Which Protein Is Best for You? (SiPhox Recommendations)

Formats: Powder vs. Shakes vs. Bars

Protein Powders

• The most versatile and cost-effective option
• Highest protein purity
• Easy to dose control (20–40 g servings)
• Best option for daily or post-workout use

Ready-to-Drink (RTD) Shakes

• Convenient and portable when traveling or short on time
• More expensive per gram of protein
• May contain added sugars, oils or stabilizers

Protein Bars

• Great for on-the-go or meal replacement
• Typically higher calorie, carb and fat content
• Not ideal for rapid post-exercise MPS, but useful for sustained energy

How to Use Protein for Best Results

Daily Target: Most people benefit from 1.0–1.6 g/kg per day, depending on activity and age.

Per-Meal Target

• Young adults: ~0.4 g/kg/meal
• Adults 60+: ~0.6 g/kg/meal
• Aim for 3–4 protein-rich meals per day. This maximizes muscle protein synthesis throughout the day.

Timing Recommendations

• Post-workout → Whey isolate (fast absorption when muscles are primed)
• Before bed → Casein (sustained release overnight)
• Between meals → Whey, plant blend, or a protein bar

A Note on Safety

Protein supplementation is considered safe for healthy individuals. Research shows no negative effects on kidney function or bone density at the intake levels discussed here. However:

• Individuals with chronic kidney disease (CKD) should follow clinician-directed intake (usually lower at 0.3–0.9 g/kg/day).
• Everyone should ensure adequate calcium and vitamin D to support bone health when consuming high protein diets.

Key Takeaway

Protein supplements are a powerful tool for supporting muscle health, metabolism, recovery, and healthy aging. The “best” protein depends on your goals, dietary restrictions, and preferences. While many options exist, high-quality whey proteins—especially isolates—deliver the strongest, most consistent results across scientific studies. Plant proteins provide valuable alternatives for those avoiding dairy, though they may require higher doses to match anabolic signaling.

Choose your format based on your needs:

• Best for overall results: Whey Isolate
• Best for sustained release: Casein
• Best plant-based option: Plant protein blend
• Best convenience: RTD shake
• Best portability: Protein bar

Supporting optimal protein intake is one of the most impactful, and most science-backed, nutrition strategies for improving long-term health.

However, with countless creatine products available—each claiming superiority—choosing the right supplement can feel overwhelming. This guide breaks down the different types of creatine and delivery formats so you can make an informed decision about which supplement is best for you.

Comparing Types of Creatine

The market offers numerous forms of creatine, from tried-and-true classics to newer, more novel variants. Each type often claims superiority in stability, bioavailability, or performance enhancement. Here’s what the science actually says.

Creatine Monohydrate (CrM): The Gold Standard

Creatine monohydrate is considered the “gold standard” of creatine supplements—and for good reason.

Why It’s Superior:

• Most researched: Nearly all creatine studies use CrM, with hundreds of peer-reviewed papers confirming its efficacy and safety
• Excellent absorption: Research shows that 99% of CrM is either absorbed into muscle tissue or excreted through urine
• Well-established safety profile: Decades of use with consistent safety data
• Most cost-effective: Typically cheaper than alternative forms

Bottom Line: If you want the most scientifically validated and affordable option, creatine monohydrate is your best choice.

Creatine Hydrochloride (HCL): Better Solubility, Same Results

Creatine HCL is a creatine molecule bonded with a hydrochloride salt, which gives it superior solubility compared to CrM.

The Reality:

• Better texture: Dissolves more easily, creating a smoother drink
• No absorption advantage: Despite marketing claims, research shows Cr-HCL is not more effective than CrM at lower or standard doses
• Higher cost: More expensive than CrM without additional benefits

Bottom Line: If grittiness bothers you and you don’t mind paying more for a smoother texture, Cr-HCL is fine—but it offers no performance advantage over monohydrate.

Buffered Creatine: A Solution to a Non-Existent Problem

Buffered creatine is marketed as “pH-correct” creatine that supposedly prevents breakdown into creatinine in stomach acid, leading to better muscle uptake at lower doses.

The Reality:

• Unnecessary: CrM is already very stable during digestion and has excellent absorption
• No added benefit: When compared head-to-head at the same dose, buffered creatine showed no advantages over CrM
• Higher cost: More expensive without proven benefits

Bottom Line: Save your money. CrM already works exceptionally well without pH buffering.

Creatine Nitrate (CrN) and Other Novel Forms

Creatine nitrate bonds creatine to a nitrate ion, which may improve solubility and potentially offer vascular benefits from the nitrate component.

The Reality:

• Good, but not better: CrN can be an effective creatine source, but offers no bioavailability advantage over CrM
• Limited research: Most alternative creatine forms lack peer-reviewed evidence supporting superiority claims
• Higher cost: Typically more expensive than CrM

Bottom Line: Novel forms sound impressive, but decades of research consistently show that creatine monohydrate remains the most effective and economical choice.

Key Takeaway: Stick with Creatine Monohydrate

With hundreds of peer-reviewed studies spanning several decades, creatine monohydrate is the best creatine supplement on the market. Alternative forms have not been proven to provide greater benefits and are almost always more expensive. Don’t fall for marketing hype—choose the supplement backed by science.

Powder vs. Pills vs. Gummies: Which Format Is Right for You?

Once you’ve decided on creatine monohydrate, you’ll need to choose a delivery format. Here’s how they compare:

1. Creatine Powder: The Proven Performer

Creatine powder (typically CrM) is the most extensively studied and effective format.

Best For: Anyone prioritizing effectiveness, flexibility, and value.

2. Creatine Pills/Capsules: The Convenient Choice

Creatine pills or capsules (typically containing CrM) offer convenience and reliable dosing.

Best For: People who travel frequently, dislike mixing powder, or prefer hassle-free supplementation.

3. Creatine Gummies/Chews: The Tasty but Problematic Option

Gummies and chews are marketed for their convenience and candy-like taste, but they come with significant concerns.

Best For: Those who absolutely cannot tolerate other forms—but proceed with caution and choose reputable, third-party tested brands.

Quick Format Comparison

How to Make Your Decision

Choose Powder If: You want the best value, dosing flexibility, and most research-backed option.

Choose Pills/Capsules If: Convenience and portability are your top priorities.

Choose Gummies If: You absolutely cannot tolerate other forms—but only buy from third-party tested brands due to significant purity concerns.

What to Look For When Shopping

Quality Indicators:

• Third-party testing (NSF, Informed Choice, or USP)
• Micronized creatine (for powder)
• Minimal additives and transparent labeling
• Reputable, established brands

Red Flags to Avoid:

• Claims of dramatic superiority to monohydrate
• Proprietary blends without disclosed amounts
• Lack of third-party testing
• Excessive marketing hype without science

Final Recommendation

For proven effectiveness, extensive research support, and value, creatine monohydrate powder remains the superior choice. If convenience is essential, pills/capsules offer a solid alternative. Gummies should be a last resort due to purity concerns and high cost.

Remember: the best creatine supplement is the one you’ll take consistently. Choose the format that fits your lifestyle, but prioritize quality, third-party testing, and—most importantly—creatine monohydrate as your active ingredient.

Book a call with one of our health coaches today to find out which creatine is right for you

Protein supplements are concentrated forms of protein extracted from food sources like dairy (whey, casein), eggs, meat, or plants (pea, soy, rice, hemp). They are designed to help people increase their daily protein intake and support lean muscle mass. You’ll find protein supplements in many forms: powders, bars, and ready-to-drink shakes.

Depending on how much the protein is processed, it’s usually labeled as:

• Concentrate: typically ~70–80% protein by weight
• Isolate: usually 90%+ protein with fewer carbs and fats
• Hydrolysate: partially pre-digested protein for faster absorption

Why Protein Matters (Even If You’re Not an Athlete)

Protein is essential for everyone. It helps build and maintain muscle, repair tissue after exercise or daily wear, support enzymes and hormones, and increase fullness to help manage appetite.

Most of your protein should still come from whole foods like lean meats, fish, eggs, dairy, tofu, lentils, and beans. Protein supplements are simply a convenient top‑up when it’s hard to meet your goals from food alone.

You might benefit from them if you’re:

• An athlete or active adult looking to support muscle recovery and performance
• Someone managing their weight who wants to stay full longer while preserving muscle
• An older adult experiencing reduced appetite or difficulty preparing protein-rich meals
• A busy professional who struggles to hit daily protein targets through food alone
• A vegan or vegetarian seeking convenient plant-based protein options

Key Benefits of Protein Supplementation

Used strategically, protein supplements can help you:

• Stimulate muscle protein synthesis (MPS)
• Build and maintain muscle and connective tissue
• Endurance and recovery after exercise or daily wear and tear
• Manage appetite, weight and body composition
• Support enzymes, hormones, and immune function

1. Stimulating Muscle Protein Synthesis (MPS)

Muscle protein synthesis (MPS) is how your body repairs and builds muscle tissue. Resistance training stimulates MPS, and consuming high-quality protein (especially sources rich in leucine, like whey) amplifies that effect.

For most people who exercise regularly, a total daily protein intake of about 1.4–2.0 g/kg body weight is sufficient to build and maintain muscle mass when combined with resistance training.

2. Build and Maintain Muscle and Connective Tissue

When you combine regular resistance training, adequate total protein intake, and consistent caloric intake, you create the ideal environment for muscle growth and strength gains. Protein supplements can make it easier to hit those daily numbers, especially around workouts or when appetite is low.

3. Endurance and Recovery after Exercise or Daily Wear and Tear

Protein isn’t just for lifters. Endurance athletes also benefit when they pair carbohydrates and protein:

Carbohydrates replenish glycogen stores, your muscles’ main fuel, while protein helps repair muscle damage and reduce soreness after long or intense sessions.

Research suggests that muscles remain more sensitive to protein intake for at least 24 hours after resistance exercise, so what matters most is hitting your daily protein target, not just pounding a shake immediately after your workout.

4. Managing Appetite, Weight and Body Composition

High‑protein diets can:

• Help reduce fat mass while maintaining or increasing lean muscle
• Improve satiety (you feel fuller for longer)
• Reduce hunger and cravings, making a calorie deficit easier to sustain

When dieting, higher protein intakes (often 1.6–2.2 g/kg) can help preserve muscle during fat loss, especially when combined with strength training.

5. Supporting Enzymes, Hormones, and Immune Function

Protein isn’t just for muscles. Amino acids are the building blocks for enzymes that drive metabolic reactions, hormones that regulate everything from appetite to stress response, and antibodies that power your immune system. When protein intake falls short, these systems compete for limited resources. Adequate intake, whether from food or supplements, ensures your body can maintain these critical functions alongside muscle repair and growth.

Metabolic and Heart Health Considerations

Metabolic Support

Certain protein supplements may offer additional benefits for people with specific health concerns.

Whey protein contains the branched-chain amino acid leucine and other bioactive components that can:

• Support insulin secretion and incretin hormones like GLP-1
• Help moderate post-meal blood sugar responses when consumed with carbohydrates
• Slow gastric emptying and increase feelings of fullness

These effects have been observed mostly in people with insulin resistance or type 2 diabetes. Protein supplements aren’t a replacement for diabetes medications but may be a useful tool under medical guidance.

Cardiovascular Support

Two protein sources are often discussed for heart health:

• Whey protein: When hydrolyzed, can release small peptides that have ACE‑inhibitory properties, which may modestly lower blood pressure in some people. Effects are generally small but meta-analyses suggest slight reductions in systolic blood pressure.
• Soy protein: Especially with isoflavones has been linked to reductions in total cholesterol, LDL cholesterol, and triglycerides in controlled trials and meta-analyses, particularly in people with high cholesterol.

These are supportive effects, not stand‑alone treatments for cardiometabolic disease.

Protein for the Aging Population

As we age, we naturally lose muscle mass and strength (sarcopenia), which can affect balance, mobility, and independence. Older adults generally benefit from higher protein intakes than the minimum Recommended Dietary Allowance (RDA).

Expert groups often recommend 1.0–1.2 g/kg body weight per day for healthy older adults, and even higher (up to ~1.5 g/kg) in some cases of illness or injury, combined with regular physical activity and resistance training when possible.

Protein supplements can be especially helpful for older adults who have reduced appetite, difficulty chewing or preparing protein‑rich meals and need convenient, easy‑to‑consume options.

Protein Pacing: How to Spread Protein Through the Day

Your body can only use so much protein at once for muscle building. Many sports nutrition experts recommend spreading protein evenly across your day, known as “protein pacing”.

A simple guideline:

• Aim for 20–40 g of high‑quality protein per meal or snack, every 3–4 hours.

Protein supplements make this easier, especially at breakfast (where protein is often low), after workouts, and during busy workdays or travel.

Safety Considerations and Potential Side Effects

For healthy individuals, protein supplementation in the ranges discussed above is generally considered safe and well-tolerated. A few things to watch for:

• Digestive issues: Some people experience bloating, gas, or stomach discomfort, especially with dairy-based proteins like whey or casein, or if they’re lactose intolerant.
• Acne and skin changes: A few studies have linked whey protein to increased acne in susceptible individuals, likely due to hormonal and insulin responses.
• Allergies: Those allergic to dairy, eggs, or soy, you should avoid proteins derived from those sources and choose alternatives like pea or rice protein instead.
• Kidney or liver disease: People with existing kidney or liver conditions must consult their healthcare provider before increasing protein intake.

Always check with your doctor or a qualified healthcare professional before starting any new supplement program, especially if you have medical conditions or take medications. Many protein supplements contain added sweeteners, flavors, gums, or other additives. Check labels to make sure the product fits your needs.

How to Use Protein Supplements Wisely

Use protein supplements to fill gaps, not to replace all your meals.

Food first: Base your diet on whole, minimally processed foods. Use supplements when it’s inconvenient or difficult to hit your protein target.

Match the protein type to your needs:

• Whey isolate or hydrolysate: Good for fast absorption and for those who want lower lactose.
• Casein: Slower-digesting; often used before bed.
• Plant-based blends (e.g., pea + rice): Great for vegans, vegetarians, or those avoiding dairy.

Watch the extras: Keep an eye on sugar, artificial sweeteners, and unnecessary fillers.

Dose smartly: Think in terms of meals and totals per day, not just “How big is my shake?”

Ready to Optimize Your Protein Intake?

Not sure where to start? We can help. If you’d like to understand your personal protein requirements, design a high-protein meal plan that fits your lifestyle, or choose a supplement that aligns with your goals, book a call with one of our health coaches, and we’ll walk you through it step by step. You can read about how to choose the best protein for you here.

Creatine is a naturally occurring compound composed of three amino acids: arginine, glycine, and methionine. Your body synthesizes creatine primarily in the liver and kidneys, and you can also obtain it from foods like salmon, red meat, and chicken.

However, getting enough creatine from food alone is challenging—you’d need to eat several pounds of meat daily to match what a single 5-gram supplement provides. This is why creatine monohydrate supplementation has become so popular.

How Does Creatine Work?

Creatine functions as an energy buffer for your muscles and brain. Most of the creatine in your body is stored in muscles as phosphocreatine (PCr). The enzyme creatine kinase (CK) facilitates PCr’s conversion into adenosine triphosphate (ATP)—your body’s primary energy currency. By supplementing with creatine monohydrate, you increase your body’s capacity to produce ATP, especially during high-intensity activities.

Key Benefits of Creatine Supplementation

Creatine monohydrate is one of the most extensively researched supplements available, with applications extending far beyond athletic performance. It’s safe, effective, and affordable, offering health benefits across various life stages—from enhancing strength and endurance to supporting bone density, brain function, and healthy aging.

Athletic Performance and Recovery

Creatine is well-established in the sporting community and recognized as a safe, legal performance-enhancing supplement by governing bodies like the United States Anti-Doping Agency (USADA).

Performance Benefits:

• Increases energy production during short-burst, high-intensity anaerobic activities
• Enhances muscular power, strength, and explosiveness (particularly in the first 10 seconds of activity)
• When combined with carbohydrates and protein, boosts muscle glycogen stores for sustained intense exercise

Recovery Benefits:

• Reduces muscle damage, inflammation, and soreness
• Athletes supplementing with creatine experience fewer musculoskeletal injuries
• When injuries do occur, recovery times are typically faster

Brain Protection: The International Society of Sports Nutrition (ISSN) recommends creatine for athletes in contact or collision sports due to its neuroprotective effects against concussions and traumatic brain injury (TBI).

Cognitive Function and Brain Health

Your brain consumes approximately 20% of your body’s total energy. Recent research shows creatine supplementation can increase brain phosphocreatine content by 5-15%, providing significant cognitive benefits.

A systematic review and meta-analysis published in Frontiers in Nutrition found that creatine supplementation positively impacts:

• Memory retention and recall
• Processing speed
• Attention and focus

By increasing PCr levels and reducing oxidative stress in the brain, creatine helps you complete mental tasks more efficiently—making it valuable not just for athletes, but for students, professionals, and anyone facing cognitive demands.

Metabolic and Cardiovascular Health

Creatine offers notable benefits for metabolic and cardiovascular function:

Blood Sugar Management: Insulin and glucose influence creatine uptake into muscle tissue. When combined with exercise, creatine supplementation can significantly improve glucose management by increasing GLUT-4 (Type 4 Glucose Transporter) expression, thereby enhancing glucose uptake into skeletal muscle and adipose tissue. This leads to improved HbA1c levels—a key marker of long-term blood sugar control.

Heart Health:

• Reduces homocysteine levels, which correlates with lower heart disease risk
• Helps manage ischemia (reduced blood flow to organs like the heart)
• Provides an alternative energy source when glucose or oxygen is limited, helping maintain heart function during stress

Healthy Aging, Muscle & Bone Support

Creatine helps counteract age-related decline in two critical areas:

Muscle Preservation (Sarcopenia Prevention): When combined with resistance training, creatine is particularly effective at combating sarcopenia (age-related muscle loss). Benefits include:

• Greater lean muscle mass gains
• Improved strength
• Enhanced ability to perform daily tasks

Bone Health: Creatine supplementation paired with resistance training helps:

• Mitigate bone density loss
• Increase bone mineral content
• Reduce fracture risk as you age

Safety Considerations and Potential Side Effects

Creatine is on the U.S. Food and Drug Administration’s Generally Recognized as Safe (GRAS) list and is backed by decades of research demonstrating its safety profile.

Potential Side Effects (Generally Mild):

• Water retention: Creatine draws water into muscle cells, which may cause a small increase in body weight (2-4 lbs)
• Digestive discomfort: Some people experience mild bloating or stomach upset, especially during the loading phase or when taking large doses on an empty stomach
• Hydration needs: Increased water intake is important when supplementing with creatine

Dosage Recommendations and Monitoring

Making an Informed Decision About Creatine

Creatine monohydrate stands out as one of the most thoroughly researched supplements available, with hundreds of peer-reviewed studies documenting its effects. The evidence consistently shows it’s safe, affordable, and effective for a wide range of health and performance goals.

Ready to start supplementing? Learn how to choose the right creatine product in our guide: How to Choose the Best Creatine Supplement.

Summary / Key Takeaways

Creatine monohydrate is one of the most well-researched and effective supplements available. It works by increasing phosphocreatine (PCr) stores in your body, providing benefits for:

✓ Athletic performance – Enhanced strength, power, and recovery

✓ Brain function – Improved memory, focus, and processing speed

✓ Metabolic health – Better glucose management and cardiovascular support

✓ Healthy aging – Protection against muscle loss and bone density decline

Bottom Line: Whether you’re an athlete, student, professional, or simply want to support your long-term health, creatine monohydrate offers significant benefits with minimal risk. At 3-5 grams per day, it’s an affordable investment in your physical and cognitive performance.

Book a call with one of our health coaches today to learn more about whether creatine is right for you

The Reality of Laboratory Testing

Here’s something that might surprise you: if you took the exact same blood sample and tested it multiple times in the same lab, on the same day, with the same equipment, you’d still get slightly different results each time. This isn’t a sign of poor lab quality, it’s an inherent characteristic of all laboratory testing, even in the most sophisticated facilities.

Every CLIA-certified laboratory (that’s the Clinical Laboratory Improvement Amendments certification that ensures quality standards) operates within accepted margins of variation. These margins are scientifically established and carefully monitored to ensure your results are reliable while acknowledging the reality of measurement precision.

Why Measurements Vary: Analytical Precision Limits

Even the most advanced laboratory equipment has inherent precision limits. When a lab measures your cholesterol, glucose, or any biomarker, the process involves:

1. Sample handling: Tiny variations in how blood is collected, transported, and stored
2. Reagent variation: The chemical substances used in testing have slight batch-to-batch differences
3. Instrument calibration: Even calibrated instruments have precision tolerances
4. Environmental factors: Temperature and humidity can subtly affect reactions
5. Human factors: Technician technique, though standardized, introduces minimal variation

Each step introduces small amounts of variability that accumulate into what’s called “analytical variation” or “measurement error.”

Understanding CLIA Allowable Error Standards

The CLIA program establishes something called “Total Allowable Error” (TEa) for each biomarker—the maximum amount of variation permitted while still providing clinically useful and reliable information. These standards are rigorously defined based on:

• The biological importance of the marker
• The technical capabilities of available testing methods
• The clinical decisions that depend on the results
• Medical usefulness and necessity

Real CLIA Error Margins for Common Biomarkers

Here are the actual CLIA Total Allowable Error limits for biomarkers commonly tracked for cardiovascular and metabolic health:

Lipid Panel:

• Total Cholesterol: ±10%
• HDL Cholesterol: ±30%
• Triglycerides: ±25%
• LDL Cholesterol: ±30% (when directly measured)

Metabolic Markers:

• Glucose: ±10% (or ±6 mg/dL, whichever is greater)
• HbA1c: ±6%

Other Key Markers:

• Creatinine: ±15%
• ALT (liver enzyme): ±20%
• TSH (thyroid): ±30%

These percentages represent the maximum acceptable deviation from the “true” value. Most high-quality labs perform well within these limits, but the standards acknowledge that some variation is inherent and acceptable.

What This Means in Practice

Let’s look at some real-world examples:

Example 1: Total Cholesterol

• Your result: 200 mg/dL
• CLIA allowable error: ±10%
• Acceptable range: 180-220 mg/dL
• If you retested immediately and got 210 mg/dL, this would be completely within expected variation

Example 2: HDL Cholesterol

• Your result: 50 mg/dL
• CLIA allowable error: ±30%
• Acceptable range: 35-65 mg/dL
• HDL has wider margins because it’s technically more challenging to measure precisely

Example 3: HbA1c

• Your result: 5.5%
• CLIA allowable error: ±6% of the value (that’s 0.33 percentage points)
• Acceptable range: 5.2-5.8%
• This marker has tighter tolerances because small changes are clinically significant

The Power of Serial Measurements

Here’s an important reality about blood testing that many people don’t realize: many biomarkers work best as serial measurements rather than single snapshots. When you establish a personal baseline through multiple tests over time, you can spot meaningful deviations much more reliably than from any single measurement.

Currently, most doctors rely on single measurements due to logistical constraints—getting patients to come in for blood draws is time-consuming and inconvenient. But this approach has a significant limitation: a single measurement of many biomarkers contains substantial uncertainty. Biomarkers can fluctuate for numerous reasons, and without a personal baseline established through repeated testing, it’s difficult to know whether a value represents your typical level or a temporary variation.

This is where regular at-home testing becomes powerful. By testing more frequently—whether monthly, quarterly, or at whatever interval makes sense for your health goals—you create a personalized reference range. You’ll know what’s normal for you, making it much easier to identify when something has genuinely changed.

Visualizing Your Error Margins

To help you better understand these natural variations in your own results, we’ve built a “See Error Bars” feature into your health reports. This tool visualizes the expected measurement variation for each of your biomarkers, based on CLIA Total Allowable Error guidelines and established analytical performance standards.

When you view your results, you can toggle this feature to see the range within which your measurement falls when accounting for analytical variation. This view helps you put your numbers in perspective and understand which changes between tests are likely to be meaningful versus those that fall within expected measurement variation. It’s like seeing your results with their natural “confidence interval”—giving you a more complete picture of your health data.

When Is a Change Actually Meaningful?

Understanding CLIA error margins helps you distinguish between measurement noise and genuine biological change. For a change between two tests to be considered truly significant (meaning it likely represents a real change in your biology rather than measurement variation), it generally needs to exceed the combined error margins of both tests.

The Importance of Patterns and Frequent Testing

This is where frequent testing becomes invaluable. A single change that falls near the boundary of measurement variation could be uncertain—but when you see the same directional change across two, three, or more consecutive tests, the likelihood that it represents a real biological shift increases dramatically.

Think of it this way:

• One test showing change: Could be measurement variation or a genuine shift—uncertain
• Two consecutive tests showing the same directional change: More likely to be real, especially if the change exceeds error margins
• Three or more tests showing a consistent trend: Very likely represents a meaningful biological change

This is why establishing a testing routine matters. Regular testing doesn’t just track your health—it helps you distinguish signal from noise with far greater confidence.

The key insight: changes need to be substantially larger than the error margin to be considered definitively meaningful from a single retest, but patterns across multiple tests provide much stronger evidence of real change, even when individual changes are modest.

Practical Implications for Tracking Your Health

Understanding test variability empowers you to:

1. Test regularly to establish your baseline: The more data points you have, the better you understand your personal normal ranges and can spot meaningful deviations.
2. Look for patterns, not just single changes: A consistent trend across multiple tests is far more meaningful than any single result or comparison between just two tests.
3. Use error margins to evaluate changes: When you see a change, compare it to the CLIA error margin (visible in your report) to understand whether it’s within expected variation or potentially meaningful.
4. Optimize testing conditions: Try to keep testing conditions similar (time of day, fasting status, recent exercise) to minimize additional sources of variation when tracking changes.
5. Understand your ranges in context: Results are best interpreted with their natural variation in mind. A value near the edge of a range, when viewed with its error margin, might actually overlap with multiple categories.
6. Use consistent testing: When tracking over time, using the same laboratory helps minimize additional variation from different testing methods and equipment.

The Bottom Line

Blood testing is incredibly valuable for monitoring health, and understanding its inherent variability makes you a more informed interpreter of your own data. The CLIA standards that govern laboratory testing aren’t limitations—they’re realistic acknowledgments of the precision achievable when measuring complex biological systems.

The real power of health tracking comes from serial measurements over time. While traditional healthcare often relies on single snapshots due to logistical constraints, regular at-home testing allows you to build a personal baseline and identify meaningful changes with much greater confidence. Our error margin visualization feature puts CLIA standards to work for you, helping you see your results with appropriate context and distinguish measurement variation from genuine biological changes—especially when viewed as patterns across multiple tests.

When you notice a change, you can quickly assess whether it exceeds the expected measurement variation and, more importantly, whether it represents a consistent pattern. This is how you turn data into actionable health insights: understanding both the precision limits of individual measurements and the power of tracking trends over time.

Note: This article is for educational purposes. Always discuss your individual test results and their interpretation with qualified healthcare providers who know your complete health history.

Why Are Ratios Important?

Ratios can capture the balance between related biomarkers, often reflecting underlying physiology better than either number by itself. Many medical conditions are characterized by an imbalance between two measures rather than an absolute high or low in one. By comparing two related values, ratios can highlight these imbalances:

• A ratio can sometimes serve as a surrogate marker for complex processes. The triglyceride-to-HDL cholesterol ratio (TG:HDL) is one well-known example. A high TG:HDL ratio suggests a pattern of abnormal lipid metabolism and insulin resistance. Studies have found TG:HDL to be a simple but effective indicator of insulin resistance and cardiometabolic risk, even more so than either triglycerides or HDL alone.
• Ratios often represent the balance of “good” vs “bad” factors. In cardiovascular medicine, the ratio of apolipoprotein B to apolipoprotein A1 (ApoB/ApoA1) is a powerful predictor of heart disease risk. ApoB is the protein on “bad” cholesterol particles (LDL, VLDL, etc.), while ApoA1 is on “good” HDL particles. The ApoB:ApoA1 ratio thus indicates the balance between atherogenic (plaque-forming) and protective cholesterol in the blood. Research has shown that even if standard cholesterol levels are normal, a higher ApoB/ApoA1 ratio correlates with more severe artery disease and a higher risk of heart attack.

Ratios are important because they provide context. They can flag a risk or abnormality only evident when comparing two values. Clinicians often use ratio markers to get a more nuanced view of metabolism, organ function, or disease risk.

Limitations of Ratio Markers – When They Don’t Add Insight

Despite their value, not every ratio is clinically useful in every situation. In many cases, if both of the individual biomarkers are in a healthy, normal range, then their ratio will also fall in a normal range and does not provide additional insight. In other words, a ratio is most informative when one or both components are abnormal or at least near the edges of normal.

Because of this, labs and clinicians often don’t bother reporting or emphasizing a ratio if both constituent values are normal. In fact, experts note that it’s hard to even define a “healthy” reference range for some ratios, precisely because these ratios are mainly used to interpret abnormal results.

This is why your report will gray out certain ratios when both biomarkers are in the healthy range as this does not provide any additional clinical insight. The bottom line: ratios are most meaningful when something is off-balance in the first place.

It’s also worth noting that some ratios are only broadly useful and not definitive on their own. A ratio outside the ideal range often points to a potential issue but usually needs to be interpreted alongside the individual values and clinical context.

Below, we’ll go through specific ratio markers, explaining what they mean, why they’re measured, and how they’re interpreted (including their limitations). We’ll also mention some calculated non-ratio markers that are derived from formulas.

Examples of Important Ratio Biomarkers

AST:ALT (De Ritis) Ratio – Liver Health Indicator

What it is: The AST:ALT ratio compares two liver enzymes: aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Both AST and ALT leak into the blood when liver cells are damaged, but they can rise in different patterns depending on the cause of liver injury.

Why it’s useful: The AST:ALT ratio helps differentiate types of liver disease and the severity of liver damage. In healthy individuals, AST and ALT levels are usually similar, yielding a ratio around 1.0. But in liver disease, their proportions change. Typically, an AST/ALT > 2 (AST is more than twice ALT) is suggestive of alcoholic liver disease or alcoholic hepatitis. On the other hand, AST/ALT < 1 (ALT higher than AST) is often seen in acute viral hepatitis or non-alcoholic fatty liver disease – conditions where ALT tends to rise more prominently.

Limitations: As mentioned earlier, if AST and ALT are normal, the ratio ~1 doesn’t tell much. It’s also not a perfect test – many patients with alcoholic liver disease might not have the “textbook” >2 ratio, and other conditions can sometimes elevate AST more than ALT. The ratio should be interpreted carefully: a very high AST:ALT ratio could even be due to muscle injury (since AST is found in muscles too) or vitamin B6 deficiency affecting ALT levels.

TSH:T4 Ratio – Thyroid Function Insight

What it is: This ratio compares thyroid-stimulating hormone (TSH) to thyroxine (T4). TSH is the pituitary hormone that signals the thyroid gland, and free T4 is the main hormone produced by the thyroid. Normally, they have an inverse relationship: if T4 is low, TSH goes up (to stimulate the thyroid), and if T4 is high, TSH drops.

Why it’s useful: In certain situations, looking at the TSH:T4 balance can refine assessment of thyroid function. One particular use is in identifying subclinical hypothyroidism – a mild underactive thyroid state where T4 is still in the normal range but TSH is slightly elevated. In subclinical hypothyroidism, the TSH:T4 ratio will be higher than normal (because T4 is relatively low for that person’s TSH level). In fact, one study introduced a “subclinical hypothyroid index” defined by the TSH:FT4 ratio, and found it helpful for diagnosing early thyroid underactivity.

Limitations: If TSH and T4 are both well within their normal ranges, the ratio doesn’t carry much independent meaning. Also, there isn’t a universally agreed “normal” range for TSH:T4 ratio in practice – doctors interpret it relative to the context. Large variations in binding proteins or acute illness can also alter free T4 levels and thus the ratio.

Free T3:Free T4 Ratio – Thyroid Hormone Conversion

What it is: This is the ratio of free triiodothyronine (FT3) to free thyroxine (FT4). T4 is converted in the body to T3, the more active thyroid hormone. So this ratio essentially measures how much T3 activity you have relative to your T4 level.

Why it’s useful: The FT3:FT4 ratio is an indicator of T4-to-T3 conversion efficiency and overall thyroid hormone balance at the tissue level. Some patients can have normal T4 but low T3 (for example, in “low T3 syndrome” during chronic illness, or in some hypothyroid patients on T4-only therapy). A reduced FT3:FT4 ratio in such cases might suggest that tissues are not adequately converting T4 to T3. On the flip side, an abnormally high T3 relative to T4 could occur in certain thyroid disorders (like T3 toxicosis or Graves’ disease with dominant T3 secretion).

Limitations: The FT3:FT4 ratio can be influenced by factors like medications, acute illness, and age. There’s no strict normal range for the ratio used in routine practice – it’s evaluated in context. If both FT3 and FT4 are normal and the person is well, the ratio is usually in a normal middle zone and not particularly scrutinized.

Cortisol to DHEA-S Ratio – Stress and Adrenal Balance

What it is: This ratio compares cortisol (the body’s main stress hormone) to DHEA-S (dehydroepiandrosterone sulfate, an adrenal hormone that can counterbalance some effects of cortisol). Both are produced by the adrenal glands. Cortisol is catabolic (breaks down tissue, increases blood sugar, suppresses immune function), whereas DHEA and its sulfate form are anabolic and supportive of immune function.

Why it’s useful: The cortisol:DHEA-S ratio is considered a marker of HPA axis balance and stress. In a healthy young person, cortisol and DHEA levels are in good proportion, especially since DHEA-S is high in youth. With aging or chronic stress, DHEA-S levels decline significantly (by age 70, DHEA-S may be only 10–20% of young adult levels) while cortisol levels do not drop as much. The result is a higher cortisol-to-DHEA ratio, indicating a shift toward catabolic, stress-related physiology.

Moreover, studies in different fields have found that higher cortisol:DHEA ratios correlate with worse outcomes in contexts like chronic pain, depression, and critical illness. A review on pain and aging noted that an elevated cortisol-to-DHEA ratio (along with low DHEA) is associated with increased frailty, poorer immune function, osteoporosis progression, and even cognitive decline.

Limitations: There is natural variability in cortisol (which follows a diurnal rhythm) and DHEA-S (which also declines with age), so the ratio’s interpretation must consider age, time of day, and individual baseline. There’s not a single “normal range” used universally for cortisol:DHEA-S ratio; instead, one looks at whether it’s higher or lower than expected for a given context. Also, both values need to be abnormal or shifting for the ratio to be meaningful. If cortisol and DHEA-S are both normal, their ratio will usually be in a reasonable range.

What About Other Calculated Markers?

In addition to ratios, many blood test results are derived calculations rather than direct measurements. These are still valuable pieces of information in your report. Here are a few examples:

• Calculated VLDL Cholesterol:Very low-density lipoprotein cholesterol (VLDL-C) is usually not measured directly. Instead, it is estimated from triglycerides, most commonly using the Friedewald equation (VLDL ≈ triglycerides ÷ 5, in mg/dL). This calculation is also used to derive LDL cholesterol (LDL = Total Cholesterol − HDL − VLDL). Calculated VLDL is useful for completing the lipid profile and estimating cardiovascular risk, but it becomes unreliable when triglycerides are very high or when samples are non-fasting. In those cases, calculated values may be suppressed or interpreted cautiously.
• Iron Saturation and Total Iron-Binding Capacity (TIBC):Iron saturation and TIBC are calculated using serum iron and unsaturated iron-binding capacity (UIBC). These calculations assume that UIBC is within a physiologically meaningful range. When UIBC is very low (< 25 µg/dL), the assumptions behind these calculations break down, and TIBC and iron saturation may become misleading. For this reason, if UIBC is below this threshold, TIBC and iron saturation are not reported, and interpretation focuses instead on the directly measured values.
• Free Androgen Index (FAI):The Free Androgen Index is a calculated marker derived from total testosterone and sex hormone–binding globulin (SHBG). It is intended as a rough estimate of androgen availability, primarily in specific clinical contexts. However, the calculation becomes unreliable when its inputs fall outside valid ranges. If SHBG is very low (< 9 nmol/L) or if total testosterone is extremely low or high (< 25.96 ng/dL or > 2018.8 ng/dL), the FAI calculation is not physiologically meaningful. In these cases, FAI is suppressed to avoid generating misleading results.
• Free Testosterone (Calculated):Calculated free testosterone is derived from total testosterone, SHBG, and albumin using established equations (such as the Vermeulen method). While calculated free testosterone generally correlates well with reference methods, it shares the same fundamental limitation as FAI: it is only as reliable as its inputs. When SHBG or total testosterone values fall outside physiologically valid ranges, the calculation can produce distorted or non-interpretable results.

The reason calculated markers are used at all is to extract additional insight without requiring extra tests, but they are not universally applicable. When the assumptions behind a calculation are violated, reporting the value can create confusion rather than clarity. Suppressing calculated markers in those situations helps ensure that reported results remain clinically meaningful and appropriately interpreted.

Key Takeaways

• Ratio biomarkers distill complex information from two related lab tests. They can be as clinically significant as the individual biomarkers by highlighting imbalances (e.g. cholesterol balance, liver enzyme patterns, thyroid feedback, stress hormones).
• If both components are normal, the ratio will typically be normal too, and generally doesn’t add new clinical insight. This is why our system (and many clinicians) will not flag or focus on a ratio in that scenario. It avoids confusion and over-interpretation.
• Ratios become important when one or both values are out of range. At that point, the ratio can help determine why and what to suspect: e.g. a high AST:ALT ratio points to a particular cause of liver injury, a high TSH:T4 ratio points to emerging hypothyroidism, etc. We automatically display these calculated ratios in such cases to give you and your healthcare provider extra context.
• Always interpret ratios in context. A ratio out of range warrants a look at its constituents: Are one or both of the underlying labs high or low? Does that fit the person’s symptoms or risk factors? The ratio is a clue, not a diagnosis.

By understanding ratio biomarkers and calculated markers, you can better appreciate what your blood test report is conveying. These derived numbers are there to enhance understanding of your health, highlighting meaningful patterns or confirming that things are well-balanced. We hope this helps you make sense of why certain ratios show up on your report only under certain conditions.

Note: This article is for educational purposes. Always discuss your individual test results and their interpretation with qualified healthcare providers who know your complete health history.