Normal Is Not Optimal
Standard reference ranges on blood tests are designed to capture the bottom and top 2.5% of the general population. The "normal" range for fasting glucose, for example, is 70–100 mg/dL. But studies consistently show that fasting glucose above 85 mg/dL — still firmly "normal" — is associated with significantly higher cardiovascular and metabolic disease risk.
The goal of tracking blood biomarkers for longevity is not to stay out of the red range. It's to optimize toward the values associated with the lowest disease risk and slowest biological aging.
Marker 1: HbA1c (Glycated Hemoglobin)
What it measures: Average blood glucose over the past 2–3 months
Standard "normal": Below 5.7% Longevity optimal: Below 5.3%
HbA1c is the most reliable single marker for long-term metabolic health. Even within the "normal" range, values above 5.3% are associated with accelerating cardiovascular and neurological aging. Higher HbA1c correlates directly with faster epigenetic aging.
If elevated: Time-restricted eating, reducing refined carbohydrates, Zone 2 exercise, and magnesium supplementation all reliably lower HbA1c.
Marker 2: Fasting Glucose
Standard "normal": 70–100 mg/dL Longevity optimal: 72–85 mg/dL
Fasting glucose above 90 mg/dL on multiple tests is a signal worth addressing even without a prediabetes diagnosis. It's an early indicator of insulin resistance.
Marker 3: Fasting Insulin
Standard "normal": Below 25 µIU/mL Longevity optimal: Below 8 µIU/mL
Fasting insulin is one of the most important longevity biomarkers and is not included in standard panels — you need to specifically request it. Elevated fasting insulin (even with normal glucose) is an early sign of insulin resistance, the metabolic dysfunction underlying cardiovascular disease, type 2 diabetes, and cognitive decline.
Marker 4: hsCRP (High-Sensitivity C-Reactive Protein)
What it measures: Systemic inflammation
Standard "normal": Below 3.0 mg/L Longevity optimal: Below 0.5 mg/L
hsCRP is the primary clinical marker for inflammaging — the chronic low-grade inflammation that drives biological aging. Values above 1.0 mg/L, even within the "normal" range, correlate with meaningfully higher cardiovascular risk and faster biological aging.
If elevated: Omega-3 supplementation (most consistent intervention), anti-inflammatory diet, eliminate trans fats and seed oils, treat sleep apnea if present.
Marker 5: ApoB (Apolipoprotein B)
Standard "normal": Below 130 mg/dL Longevity optimal: Below 80 mg/dL (or below 60 mg/dL for high-risk individuals)
ApoB is a more precise cardiovascular risk marker than LDL-C. Each ApoB particle can embed in arterial walls — ApoB counts all atherogenic particles, while LDL-C only estimates one component.
Peter Attia and most longevity-focused physicians now use ApoB as the primary cardiovascular risk marker. Request it specifically — it's not on standard panels.
Marker 6: Triglycerides
Standard "normal": Below 150 mg/dL Longevity optimal: Below 80 mg/dL
Triglycerides are one of the most modifiable lipid markers. They respond dramatically to dietary changes — reducing refined carbohydrates and increasing omega-3 intake typically lowers triglycerides by 20–40% within 4 weeks.
High triglycerides combined with low HDL is a classic sign of insulin resistance and metabolic syndrome.
Marker 7: HDL Cholesterol
Standard "normal": Above 40 mg/dL (men), above 50 mg/dL (women) Longevity optimal: Above 60 mg/dL (men), above 70 mg/dL (women)
HDL ("good cholesterol") has complex effects on longevity. While simply raising HDL with medications hasn't consistently improved outcomes, naturally high HDL from exercise and healthy diet is strongly associated with cardiovascular longevity.
The triglyceride-to-HDL ratio is a useful insulin resistance proxy: below 1.5 is optimal; above 3.0 suggests significant insulin resistance.
Marker 8: Vitamin D (25-OH Vitamin D)
Standard "normal": 20–100 ng/mL Longevity optimal: 40–60 ng/mL
The standard lower bound of "normal" (20 ng/mL) is set for bone health. For longevity and immune function, 40–60 ng/mL is consistently associated with better outcomes.
Over 40% of adults in developed countries fall below 30 ng/mL. This is one of the most impactful and inexpensive deficiencies to fix.
Marker 9: Omega-3 Index
What it measures: EPA + DHA as a percentage of red blood cell fatty acids Standard testing: Not commonly included; request specifically Longevity optimal: Above 8%
The omega-3 index is a stronger predictor of sudden cardiac death than LDL cholesterol in multiple studies. Most people eating typical Western diets have an index of 4–5%.
Marker 10: Homocysteine
Standard "normal": Below 15 µmol/L Longevity optimal: Below 9 µmol/L
Elevated homocysteine is a risk factor for cardiovascular disease, cognitive decline, and Alzheimer's disease. It's driven by poor methylation — often due to B12 and folate deficiency or MTHFR gene variants.
Easily treated with methylated B12 (methylcobalamin) and methylfolate supplementation.
Marker 11: TSH (Thyroid-Stimulating Hormone)
Standard "normal": 0.5–4.5 mIU/L Longevity optimal: 1.0–2.5 mIU/L
Thyroid function profoundly affects metabolism, energy, cognitive function, and mood. Values at the upper end of "normal" can indicate subclinical hypothyroidism with real quality-of-life and longevity implications.
If TSH is above 2.5, also request Free T3 and Free T4 for a complete picture.
Marker 12: Albumin
Standard "normal": 3.5–5.5 g/dL Longevity optimal: Above 4.5 g/dL
Albumin is a protein produced by the liver and is a surprisingly strong longevity marker. It's included in many composite biological age calculators. Declining albumin (even within the normal range) is associated with increased frailty and all-cause mortality.
It reflects nutritional status, liver function, and systemic inflammation.
How to Use This Information
Step 1: Get your annual panel and request additions — specifically ask for: fasting insulin, ApoB, hsCRP, omega-3 index, 25-OH Vitamin D, and homocysteine.
Step 2: Compare to longevity optimal ranges, not just "normal" flags.
Step 3: Track trends over time. A single reading is a snapshot. Changes over 6–12 months tell you whether your interventions are working.
Step 4: Use the results to prioritize. A high hsCRP and low omega-3 index together point to a clear, inexpensive intervention. An elevated ApoB might warrant a conversation about cardiovascular risk management.
Content is for educational purposes only. Not medical advice. Always discuss blood test results with your healthcare provider.