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BIOMARKER LIBRARY

56 biomarkers. Searchable. Free.

Reference vs optimal ranges for the biomarkers most commonly tracked on peptide, GLP-1, and optimization protocols. Hormones · cardiovascular · metabolic · thyroid · liver · kidney · hematology · nutrient · recovery (wearable). Search by name, panel, or what it measures.

56 of 56 biomarkers
GROWTH
IGF-1
Insulin-like Growth Factor 1
The primary downstream mediator of growth hormone, and the main lab marker used to monitor GH secretagogue protocols.
Optimal: Upper quartile for age - typically 180–240 ng/mL for ages 30–50
IGFBP-3
IGF Binding Protein 3
Binds ~90% of circulating IGF-1 - the IGF-1:IGFBP-3 molar ratio refines interpretation of GH-axis activity.
Optimal: Age-appropriate upper half of reference range
CARDIOVASCULAR
ApoB
Apolipoprotein B
The single most accurate serum marker of atherosclerotic cardiovascular risk - more predictive than LDL-C.
Optimal: <80 mg/dL (general population); <60 mg/dL (existing CVD or high risk)
LDL-C
LDL Cholesterol
The classic cholesterol measure - informative but inferior to ApoB for particle-count-driven risk assessment.
Optimal: <70 mg/dL in established CVD; <100 in primary prevention
HDL-C
HDL Cholesterol
The "good" cholesterol - reverse cholesterol transport. Often inversely correlated with cardiovascular risk, but not the strongest signal.
Optimal: 50–80 mg/dL - extremely high levels (>90) carry their own concerns
Triglycerides
Serum Triglycerides
Circulating fat in transit - among the most diet-responsive lipid markers. Drops fast on GLP-1s and low-carb diets.
Optimal: <100 mg/dL · ideal <80 mg/dL fasting
Lp(a)
Lipoprotein(a)
The genetic cardiovascular risk marker - fixed for life, not lifestyle-modifiable. Tested once; if elevated, drives lifelong risk management.
Optimal: <30 mg/dL - but the value is set genetically
Homocysteine
Plasma Homocysteine
Methylation status marker - elevation reflects B-vitamin (B12, folate, B6) sufficiency and overall methylation capacity.
Optimal: <8 mcmol/L for cardiovascular and cognitive optimization
LDL-P
LDL Particle Number
The particle-count version of LDL - captures cardiovascular risk that LDL-C alone can miss, especially in insulin resistance.
Optimal: <1000 nmol/L; <800 nmol/L for prior events or high risk
ApoA1
Apolipoprotein A1
The structural protein of HDL - a more reliable marker of protective cholesterol function than HDL-C alone.
Optimal: ≥140 mg/dL; ApoB:ApoA1 ratio <0.6
Lp-PLA2
Lipoprotein-Associated Phospholipase A2
Vascular-specific inflammation - more specific to arterial wall biology than hs-CRP.
Optimal: <200 nmol/min/mL
NT-proBNP
N-Terminal Pro B-Type Natriuretic Peptide
Cardiac stress and volume-overload marker - useful ruling out heart failure and monitoring cardiac strain.
Optimal: <125 pg/mL
HORMONE
Total Testosterone
Total Testosterone
The most commonly measured hormone in men - but rarely the most informative without the context of SHBG and free testosterone.
Optimal: 500–900 ng/dL is a common target in optimization practice
Estradiol
Estradiol (E2) - Sensitive Assay
The primary estrogen in both sexes. In men, tight tracking matters on testosterone-modulating protocols to catch both excess and deficiency.
Optimal: Men: 20–35 pg/mL on TRT; premenopausal women: phase-dependent
Free Testosterone
Free (Bioavailable) Testosterone
The fraction of testosterone unbound to SHBG - what tissues actually use. Often more informative than total.
Optimal: 15–25 ng/dL on TRT; 10–20 ng/dL eugonadal
SHBG
Sex Hormone Binding Globulin
The carrier protein that regulates how much testosterone and estradiol are actually bioavailable.
Optimal: 25–55 nmol/L is a common optimization target in men
LH
Luteinizing Hormone
Pituitary signal driving testosterone production in men + ovulation in women - first marker to move on enclomiphene/HCG protocols.
Optimal: Men: 4–8 mIU/mL when natural axis intact
FSH
Follicle Stimulating Hormone
Companion to LH - drives sperm production in men and follicle maturation in women. The fertility marker.
Optimal: Men: 1.5–8 mIU/mL when fertile
Cortisol AM
Morning Cortisol (Serum)
The HPA axis stress hormone - peaks early morning. Low AM cortisol signals adrenal insufficiency; high signals chronic stress or HPA dysfunction.
Optimal: 10–18 mcg/dL at 8 AM
DHEA-S
Dehydroepiandrosterone Sulfate
Adrenal androgen reserve - the precursor pool the body draws from for sex hormone synthesis. Declines steeply with age.
Optimal: Upper quartile for age - typically 300+ mcg/dL in 30s, 250+ in 40s
Prolactin
Prolactin
Pituitary hormone - elevated prolactin suppresses LH/FSH and testosterone. Often the hidden cause of low libido or ED.
Optimal: Men: 4–10 ng/mL · keeps HPG axis suppression at bay
Progesterone
Progesterone
Cycle-phase-critical reproductive hormone with implications for sleep, mood, and GABAergic tone.
Optimal: Mid-luteal >10 ng/mL indicates ovulation; optimal varies by phase
METABOLIC
HbA1c
Glycated Hemoglobin (A1C)
Reflects average blood glucose over the prior ~90 days - the gold-standard measure of chronic glycemic control.
Optimal: <5.4% (metabolic optimization target)
Fasting Glucose
Fasting Plasma Glucose
Single-snapshot glucose control measure - sensitive to acute stress but foundational for metabolic tracking.
Optimal: 70–89 mg/dL is the metabolic-optimization target
Fasting Insulin
Fasting Insulin
The earliest detectable signal of insulin resistance - moves before glucose, often before HbA1c.
Optimal: <10 mIU/L · ideally 2–6 mIU/L for metabolic optimization
C-Peptide
C-Peptide
Endogenous insulin production marker - cleaner than fasting insulin for measuring what your pancreas is actually making.
Optimal: 0.9–2.5 ng/mL (fasting) in metabolically healthy adults
Uric Acid
Serum Uric Acid
Classic gout marker, but also a sensitive signal of fructose intake, metabolic syndrome, and renal function.
Optimal: 4.0–6.0 mg/dL
INFLAMMATION
hs-CRP
High-Sensitivity C-Reactive Protein
The most commonly used marker of low-grade systemic inflammation and cardiovascular risk.
Optimal: <1.0 mg/L - often <0.5 mg/L in highly optimized individuals
IL-6
Interleukin-6
A primary upstream driver of hs-CRP and systemic inflammation - aging, obesity, and chronic disease all raise it.
Optimal: <2 pg/mL
THYROID
TSH
Thyroid Stimulating Hormone
The pituitary signal to the thyroid - first-line thyroid test, but optimization requires free T4 + T3 context.
Optimal: 0.5–2.0 mIU/L is a common optimization target
Free T4
Free Thyroxine
The bioactive thyroid hormone in storage form - gets converted to active T3 in peripheral tissues.
Optimal: 1.1–1.5 ng/dL is a common optimization target
Free T3
Free Triiodothyronine
The biologically active thyroid hormone - what your tissues actually use. Symptoms correlate better with Free T3 than TSH.
Optimal: 3.2–4.2 pg/mL is a common optimization target
Reverse T3
Reverse Triiodothyronine
The "off-switch" thyroid hormone - high Reverse T3 blocks T3 receptors and signals chronic stress, illness, or overtraining.
Optimal: <15 ng/dL · ratio Free T3 / Reverse T3 > 0.2
NUTRIENT
Vitamin D
25-Hydroxyvitamin D (25-OH-D)
The storage form of vitamin D - core nutrient status marker, deficient in ~40% of adults.
Optimal: 50–80 ng/mL is a common optimization target
Ferritin
Ferritin (Iron Storage)
Iron storage protein - the best single marker of iron status, but an acute phase reactant too.
Optimal: 70–150 ng/mL is a common optimization target
Vitamin B12
Vitamin B12 (Cobalamin)
Essential for nerve function and red blood cell production - deficiency is common, especially on metformin and in vegetarians.
Optimal: 500–900 pg/mL is a common optimization target
Iron
Serum Iron
Circulating iron - must be interpreted with ferritin, TIBC, and transferrin saturation, not in isolation.
Optimal: 80–130 μg/dL
TIBC
Total Iron Binding Capacity
Transferrin capacity - elevated in iron deficiency, suppressed in iron overload.
Optimal: 250–400 μg/dL
Magnesium RBC
Red Blood Cell Magnesium
Intracellular magnesium - far more sensitive to deficiency than serum magnesium, which the body defends aggressively.
Optimal: 6.0–6.8 mg/dL
Zinc
Plasma Zinc
Essential trace mineral for immunity, wound healing, and testosterone production - commonly deficient in vegetarian diets.
Optimal: 90–120 μg/dL
RECOVERY
HRV
Heart Rate Variability
Autonomic nervous system readout - the most informative daily signal for stress, recovery, and training load.
Optimal: Individual baseline +10–20%; trend > absolute value
Resting Heart Rate
Resting Heart Rate (RHR)
The most cardiovascular-fitness-correlated daily metric - lower typically indicates better trained aerobic capacity.
Optimal: 50–65 bpm in trained adults; trend matters more than absolute
Sleep Score
Nightly Sleep Quality Score
Composite sleep metric from wearables - combines duration, efficiency, and deep/REM ratios into one number.
Optimal: 80+ (Oura) or "Fully Recovered" (Whoop) consistently
VO2 Max
Maximal Aerobic Capacity
The strongest single predictor of all-cause mortality - aerobic fitness quantified.
Optimal: Top quartile for age - typically >50 (men) or >40 (women)
LIVER
ALT
Alanine Aminotransferase
Liver enzyme - sensitive to hepatic fat (NAFLD) and the most common abnormality on routine panels.
Optimal: <25 U/L is a common metabolic-optimization target
AST
Aspartate Aminotransferase
Companion liver enzyme to ALT - also rises with muscle damage. AST/ALT ratio gives etiology hints.
Optimal: <25 U/L
GGT
Gamma-Glutamyl Transferase
The most alcohol-sensitive liver enzyme - also a sensitive marker of oxidative stress and bile duct issues.
Optimal: <25 U/L (men) · <20 U/L (women)
Bilirubin
Total Bilirubin
Heme breakdown product - elevations signal liver dysfunction, hemolysis, or the benign Gilbert syndrome variant.
Optimal: 0.3–1.0 mg/dL
Albumin
Serum Albumin
The main liver-synthesized serum protein - low levels signal liver dysfunction, malnutrition, or chronic disease.
Optimal: 4.3–5.0 g/dL
KIDNEY
eGFR
Estimated Glomerular Filtration Rate
The headline kidney function number - reflects how well your kidneys filter waste. Declines with age and accelerates with metabolic disease.
Optimal: >90 mL/min/1.73m² for healthy adults
Creatinine
Serum Creatinine
Direct kidney filtration marker - input to eGFR calculation. Higher in muscular individuals.
Optimal: Within range; trend matters more than absolute
Cystatin C
Cystatin C
Kidney function marker independent of muscle mass - more accurate than creatinine in the muscular, elderly, or ill.
Optimal: 0.5–0.9 mg/L
HEMATOLOGY
Hematocrit
Hematocrit (HCT)
Percent of blood volume that is red blood cells - the key marker to monitor on TRT and GH protocols.
Optimal: Men on TRT: <52% sustained · Women: <47%
Hemoglobin
Hemoglobin (Hgb)
The oxygen-carrying protein in red blood cells - paired with hematocrit; either elevation matters on TRT.
Optimal: Men on TRT: <17.5 g/dL sustained · Women: <15 g/dL
WBC
White Blood Cell Count
Total immune-cell count - chronic low-grade elevation correlates with inflammation, mortality, and metabolic disease.
Optimal: 4.5–6.5 K/μL (chronically <6 correlates with lower all-cause mortality)
Platelets
Platelet Count
Clotting-cell count - abnormal values signal bone marrow issues, inflammation, or bleeding risk.
Optimal: 180–320 K/μL
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Informational only - not medical advice. Reference ranges vary by lab and individual context. Work with a licensed provider to interpret your specific results.