Overview.
Biological aging is driven by measurable processes: glycation, inflammation, oxidative stress, and metabolic dysfunction. Blood biomarkers reveal how these processes are progressing in your body. The right tests, interpreted with optimal (not just 'normal') ranges, can identify aging acceleration years before symptoms appear—giving you time to intervene.
Ranked biomarkers.
#1 HbA1c (Glycated Hemoglobin)
Glycation—the bonding of sugar to proteins—is a fundamental aging mechanism. HbA1c measures this directly over 90 days. Every 1% increase correlates with increased all-cause mortality.
Optimal range: < 5.3% (lab normal: < 5.7%)
Key insight: Most longevity physicians target under 5.0% for optimal healthspan. Postprandial glucose spikes accelerate glycation even when fasting glucose appears normal.
#2 ApoB (Apolipoprotein B)
Cardiovascular disease remains the leading cause of death. ApoB counts all atherogenic particles—a better predictor than LDL-C. Atherosclerosis starts decades before heart attacks.
Optimal range: < 80 mg/dL (aggressive: < 60 mg/dL)
Key insight: Peter Attia and other longevity physicians recommend lifetime ApoB suppression. The lower you maintain it, the slower plaque accumulation.
#3 hs-CRP (High-Sensitivity C-Reactive Protein)
Chronic low-grade inflammation accelerates every aging pathway. hs-CRP captures systemic inflammation that standard CRP misses.
Optimal range: < 1.0 mg/L (lab normal: < 3.0 mg/L)
Key insight: Persistent elevation above 1.0 doubles cardiovascular risk independent of cholesterol. Sources include visceral fat, poor sleep, and gut dysfunction.
#4 Fasting Insulin
Insulin resistance precedes type 2 diabetes by 10-15 years. High insulin—even with normal glucose—indicates metabolic dysfunction and accelerates aging.
Optimal range: < 5 μIU/mL (lab normal: < 25 μIU/mL)
Key insight: Most labs use ranges that include the metabolically unhealthy population. Optimal is dramatically lower than 'normal'.
#5 Homocysteine
Elevated homocysteine indicates impaired methylation—critical for DNA repair, detoxification, and neurotransmitter synthesis. It's also directly toxic to blood vessels.
Optimal range: < 10 μmol/L (lab normal: < 15 μmol/L)
Key insight: Often reflects B12, folate, or B6 deficiency. Easy to optimize with methylated B vitamins if elevated.
#6 Vitamin D (25-OH)
Vitamin D functions as a hormone affecting 1,000+ genes including immune function, bone health, and muscle strength. Deficiency accelerates frailty.
Optimal range: 40-60 ng/mL (lab normal: > 30 ng/mL)
Key insight: Most people are insufficient. Dark-skinned individuals, those avoiding sun, and people over 50 need supplementation.
#7 Ferritin
Iron is pro-oxidant when excessive. Elevated ferritin correlates with cardiovascular disease, diabetes, and liver dysfunction. But too low causes fatigue and anemia.
Optimal range: 40-100 ng/mL (varies by sex)
Key insight: The longevity sweet spot is mid-range. Regular blood donation can lower elevated ferritin.
#8 Triglycerides
Elevated triglycerides indicate carbohydrate intolerance and metabolic dysfunction. The triglyceride-to-HDL ratio predicts insulin resistance.
Optimal range: < 100 mg/dL (lab normal: < 150 mg/dL)
Key insight: Fasted triglycerides under 70 with HDL above 60 indicates excellent metabolic health. This ratio matters more than either number alone.
#9 TSH (Thyroid Stimulating Hormone)
Thyroid dysfunction affects metabolism, cognition, cardiovascular health, and body composition. Both hypo- and hyperthyroidism accelerate aging.
Optimal range: 1.0-2.0 mIU/L (lab normal: 0.4-4.0 mIU/L)
Key insight: Many people feel better with TSH in the lower-normal range. Optimal is narrower than the wide 'normal' range.
#10 RDW (Red Cell Distribution Width)
RDW measures variation in red blood cell size. Elevated RDW predicts all-cause mortality independent of anemia—it's a marker of systemic stress and inflammation.
Optimal range: < 13% (lab normal: 11.5-14.5%)
Key insight: Often overlooked on CBC panels. Elevation can indicate nutritional deficiencies, inflammation, or oxidative stress.
How to test.
Request a comprehensive metabolic panel with lipids, HbA1c, fasting insulin, hs-CRP, homocysteine, and vitamin D. Most can be done through your primary care physician or direct-to-consumer labs like Quest or LabCorp. Test annually minimum; every 6 months if optimizing.
FAQs.
How often should I test these longevity biomarkers?
Annual testing is the minimum for tracking. If actively optimizing (changing diet, supplements, or lifestyle), test every 3-6 months to gauge response. HbA1c reflects 90 days, so testing more frequently than quarterly isn't informative.
Why are optimal ranges different from lab normal ranges?
Lab 'normal' ranges are based on population averages—including people with undiagnosed conditions. Optimal ranges are based on what correlates with lowest disease risk and longest lifespan in research studies.
Can I track these with a home test?
Some biomarkers like HbA1c and lipids have reliable at-home tests. Others like ApoB and homocysteine typically require lab draws. Continuous glucose monitors (CGMs) can complement HbA1c by showing real-time patterns.
What if my doctor says my results are 'normal'?
Normal doesn't mean optimal. Share your longevity goals with your doctor and discuss optimal ranges. Many physicians are receptive when patients are informed and engaged. You can also work with longevity-focused practitioners.
Verdict.
These 10 biomarkers provide a comprehensive picture of your biological aging. Prioritize HbA1c, ApoB, and hs-CRP as the 'big three' that most impact healthspan. Regular testing with optimal (not just normal) targets enables early intervention—the key to extending healthy years.