Longevity Blood Tests: What to Track and Why Your Doctor Doesn't Order Them (2026)

Your annual physical probably includes a basic metabolic panel and a standard lipid test. Your doctor checks a few numbers, tells you everything looks "normal," and sends you home for another year.

Here's the problem: "normal" ranges on standard blood work are based on population averages – which include people who are overweight, sedentary, metabolically unhealthy, and on their way to chronic disease. Falling within "normal" range often just means you're not yet clinically sick. It tells you nothing about how fast you're aging, how well your mitochondria are functioning, or whether your metabolic health is quietly deteriorating years before a diagnosis.

Longevity medicine operates on a fundamentally different standard. Instead of "are you sick yet?" the question becomes "are you aging optimally?" The biomarkers that answer this question are often cheap, widely available, and almost never included on a standard panel.

This guide breaks down every blood biomarker that matters for longevity – organized into three tiers based on cost, availability, and how actionable the data is – with optimal ranges that differ (sometimes dramatically) from what your lab report flags as "normal."

TL;DR

• Standard blood panels miss most longevity-relevant biomarkers – "normal" ranges are not optimal ranges
• Tier 1 (Essential): Fasting glucose, HbA1c, fasting insulin/HOMA-IR, hsCRP, ApoB, vitamin D, CBC – cheap, available everywhere, immediately actionable
• Tier 2 (Longevity-Specific): Homocysteine, omega-3 index, GGT, uric acid, DHEA-S, full thyroid panel – moderately priced, reveal aging-specific patterns
• Tier 3 (Advanced): GlycanAge, epigenetic clocks, NAD+ levels, telomere length, inflammatory cytokines – expensive, emerging, best for tracking interventions over time
• Optimal ranges are tighter than lab "normal" – being in the middle of the reference range is often not good enough
• You can order most of these tests yourself through direct-to-consumer lab services without a doctor's order
• Test at baseline, then retest every 6-12 months to track trends

Why Standard Blood Panels Miss Longevity Markers

When your doctor orders "routine labs," you typically get a basic metabolic panel (BMP), a standard lipid panel, and maybe a complete blood count (CBC). This covers the basics – kidney function, electrolytes, blood sugar, and a rough picture of cholesterol.

The issue is what's missing.

Your standard lipid panel doesn't include ApoB. ApoB (apolipoprotein B – the protein particle that carries cholesterol into your artery walls and drives atherosclerosis) is a far better predictor of cardiovascular risk than LDL cholesterol. A 2021 meta-analysis in JAMA Cardiology involving over 390,000 participants found that ApoB was the single strongest lipid-related predictor of cardiovascular events – superior to LDL-C, non-HDL-C, and triglycerides (Sniderman et al., 2021). Yet most doctors still don't order it.

Your fasting glucose is checked, but fasting insulin isn't. Insulin resistance (when your cells stop responding efficiently to insulin, forcing your pancreas to produce more to maintain normal blood sugar) can develop 10-15 years before fasting glucose becomes abnormal. By the time glucose is elevated, you're already significantly metabolically compromised. A fasting insulin test costs about $15-30, and it reveals the problem a decade earlier.

Inflammation markers stop at the basics. If you're lucky, your doctor orders CRP (C-reactive protein). More likely, they don't. And almost no standard panel includes homocysteine (an amino acid byproduct of methylation that, when elevated, damages blood vessel walls and signals impaired detoxification capacity), omega-3 index, or the specific inflammatory cytokines (signaling molecules your immune cells use to coordinate inflammatory responses) that drive chronic, low-grade inflammation associated with aging.

Hormonal aging is ignored entirely. DHEA-S (dehydroepiandrosterone sulfate – the most abundant steroid hormone in your body, which declines roughly 2-3% per year starting in your late 20s) drops steadily with age, and its decline correlates with immune dysfunction, muscle loss, cognitive decline, and increased mortality. It's cheap to test. It's almost never ordered.

The result: millions of people are told they're healthy because they fall within population-based reference ranges, while their actual metabolic, inflammatory, and hormonal markers are silently trending in the wrong direction.

Key Takeaway: Standard annual physicals miss most longevity-relevant markers. A standard lipid panel does not include ApoB or Lp(a). A basic metabolic panel does not include fasting insulin or hsCRP at high sensitivity. You need to specifically request these tests — and knowing what to ask for is the first step toward data-driven longevity.

Tier 1: Essential Biomarkers (Cheap, Available Everywhere)

These are the foundation. Every one of them is available at any commercial lab, costs $15-50 per marker, and provides immediately actionable data. If you do nothing else, get these tested annually.

Fasting Glucose

What it measures: The concentration of glucose (sugar) in your blood after 8-12 hours without eating. Reflects your body's baseline ability to regulate blood sugar.

Why it matters: Elevated fasting glucose – even within the "normal" range – is associated with increased all-cause mortality. A study analyzing data from approximately 700,000 adults found that cardiovascular disease risk begins rising at glucose levels well below the 100 mg/dL threshold for "prediabetes" (Emerging Risk Factors Collaboration, 2010, The Lancet).

If yours is high: Cut refined carbohydrates. Add resistance training (shown to improve glucose disposal independently of weight loss). Walk for 15 minutes after meals – a 2022 meta-analysis in Sports Medicine found post-meal walking reduces glucose spikes by 17-24%. Consider berberine or chromium supplementation if lifestyle changes are insufficient.

HbA1c (Glycated Hemoglobin)

What it measures: The percentage of your hemoglobin (the oxygen-carrying protein in red blood cells) that has glucose attached to it. Because red blood cells live approximately 90-120 days, HbA1c reflects your average blood sugar over the past 2-3 months – a much better picture than a single fasting glucose reading.

Why it matters: HbA1c is one of the strongest single predictors of healthspan. Each 1% increase above 5.0% is associated with significantly increased risk of cardiovascular disease, cognitive decline, kidney disease, and all-cause mortality. The Emerging Risk Factors Collaboration found that non-diabetic individuals with HbA1c in the 5.5-6.0% range had substantially elevated cardiovascular risk compared to those below 5.0% (Emerging Risk Factors Collaboration, 2010, The Lancet).

If yours is high: This is a dietary and metabolic problem first. Reduce glycemic load (the total blood sugar impact of a meal, accounting for both carbohydrate type and quantity). Increase fiber intake to 30-40g/day. Resistance training and high-intensity interval training both independently lower HbA1c. Magnesium supplementation (glycinate or threonate, 200-400mg/day) has shown modest HbA1c reductions in clinical trials.

Fasting Insulin & HOMA-IR

What it measures: Fasting insulin measures how much insulin (the hormone your pancreas produces to shuttle glucose into cells) your body needs to maintain a normal fasting blood sugar. HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) combines your fasting insulin and fasting glucose into a single score that estimates how resistant your cells are to insulin's effects.

HOMA-IR formula: (Fasting Insulin in μIU/mL x Fasting Glucose in mg/dL) / 405

Why it matters: This is arguably the most important test your doctor doesn't order. Fasting insulin becomes elevated years -- sometimes a full decade -- before fasting glucose rises out of range. If your fasting glucose is 88 mg/dL but your fasting insulin is 18 μIU/mL, your pancreas is working overtime to maintain that "normal" glucose. You have insulin resistance. And unless someone checks your insulin, no one will catch it.

Insulin resistance is a root driver of nearly every chronic disease associated with aging: type 2 diabetes, cardiovascular disease, Alzheimer's disease (increasingly called "type 3 diabetes"), non-alcoholic fatty liver disease, and certain cancers. Multiple studies have identified HOMA-IR as one of the strongest metabolic predictors of future disease burden in middle-aged adults, reflecting the central role of insulin resistance in age-related metabolic decline.

If yours is high: Reduce sugar and refined carbohydrate intake. Time-restricted eating (confining meals to an 8-10 hour window) has been shown to improve insulin sensitivity in multiple randomized controlled trials. Cold exposure (cold showers, ice baths) activates GLUT4 transporters (proteins embedded in cell membranes that move glucose inside the cell without requiring insulin) and may independently improve glucose uptake. Resistance training is the single most effective exercise modality for improving insulin sensitivity. Berberine has been shown in clinical trials to reduce HOMA-IR by 30-45%.

hsCRP (High-Sensitivity C-Reactive Protein)

What it measures: CRP is a protein produced by your liver in response to inflammation. The "high-sensitivity" version of the test (hsCRP) can detect very low levels of chronic, systemic inflammation – the kind that doesn't make you feel sick but accelerates aging at the cellular level.

Why it matters: Chronic low-grade inflammation – sometimes called inflammaging – is one of the 12 hallmarks of aging. It drives endothelial damage (injury to the thin layer of cells lining your blood vessels), accelerates telomere shortening, impairs mitochondrial function, and promotes cellular senescence (the state where cells stop dividing but refuse to die, secreting inflammatory molecules that damage neighboring tissue).

A 2017 landmark trial (CANTOS, published in The New England Journal of Medicine) demonstrated that reducing inflammation alone – without changing cholesterol levels – reduced cardiovascular events by 15% (Ridker et al., 2017). hsCRP below 0.5 mg/L is associated with substantially lower all-cause mortality compared to the "normal" range of 1-3 mg/L.

If yours is high: Rule out acute causes first (infection, injury, autoimmune conditions). For chronic elevation: omega-3 fatty acids (EPA + DHA at 2-4g/day) reliably reduce hsCRP by 20-35% in clinical trials. Curcumin (as a bioavailable formulation, 500-1000mg/day) has anti-inflammatory effects demonstrated in meta-analyses. Regular aerobic exercise reduces hsCRP by approximately 20-30%. Adequate sleep (7-8 hours) – sleep deprivation alone can double hsCRP levels.

Lipid Panel: Focus on ApoB

What it measures: A standard lipid panel gives you total cholesterol, LDL-C, HDL-C, and triglycerides. But for longevity purposes, the single most important number is ApoB – the count of atherogenic (artery-damaging) lipoprotein particles in your blood.

Every LDL particle, every VLDL particle (very low-density lipoprotein – a triglyceride-rich particle produced by the liver), and every Lp(a) particle (lipoprotein little-a – a genetically determined lipoprotein particle that independently drives cardiovascular risk) carries exactly one ApoB molecule. So ApoB is essentially a particle count – and particle count matters more than cholesterol concentration.

Why it matters: Cardiovascular disease remains the number one cause of death globally. ApoB captures your atherogenic risk more accurately than any other single lipid marker because it counts all the particles that can enter your artery wall and initiate plaque formation – not just LDL.

A person with "normal" LDL-C but elevated ApoB has significantly more cardiovascular risk than their LDL number suggests. The European Atherosclerosis Society consensus statement now recommends ApoB as the preferred lipid marker for cardiovascular risk assessment (Nordestgaard & Langsted, 2020).

If ApoB is high: Dietary changes (reducing saturated fat and refined carbohydrates) can lower ApoB by 10-20%. Regular aerobic exercise improves the LDL particle size profile. Omega-3 supplementation (EPA specifically, 2-4g/day) reduces VLDL particles and triglycerides. If lifestyle changes are insufficient, this is a conversation to have with your physician about pharmacological intervention – statins and PCSK9 inhibitors reduce ApoB by 30-60%.

Note on Lp(a): This is genetically determined – it doesn't change much with diet, exercise, or supplements. Test it once. If it's elevated (>50 nmol/L), you have an independent cardiovascular risk factor that warrants more aggressive management of your other modifiable risks.

Vitamin D (25-Hydroxy)

What it measures: 25-hydroxyvitamin D is the circulating form of vitamin D, a secosteroid hormone (a steroid-like molecule produced in your skin from sunlight exposure that regulates over 1,000 genes) that influences immune function, bone metabolism, gene expression, and inflammatory regulation.

Why it matters: An estimated 42% of US adults are vitamin D deficient (below 20 ng/mL), and roughly 70% have suboptimal levels (below 40 ng/mL). Vitamin D insufficiency is associated with increased all-cause mortality, accelerated immune aging, higher cancer incidence, impaired muscle function, and elevated inflammatory markers.

A 2014 meta-analysis in The BMJ found that individuals with 25-OH vitamin D levels below 30 ng/mL had a 35% higher risk of cardiovascular death and a 14% higher risk of all-cause mortality compared to those with levels above 40 ng/mL (Chowdhury et al., 2014).

If yours is low: Supplement with vitamin D3 (cholecalciferol). Most people need 4,000-5,000 IU/day to maintain levels in the 40-60 ng/mL range – far more than the RDA of 600-800 IU. Co-supplement with vitamin K2 (MK-7 form, 100-200 mcg/day) to ensure proper calcium routing. Retest after 3 months, as individual absorption varies significantly.

Complete Blood Count (CBC)

What it measures: CBC counts your red blood cells, white blood cells, and platelets, along with hemoglobin concentration and hematocrit (the percentage of your blood that is red blood cells). It also breaks down white blood cell types into a differential – neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Why it matters: The CBC is standard – but few doctors interpret it through a longevity lens. Two ratios buried in the data are emerging as powerful aging biomarkers:

Neutrophil-to-lymphocyte ratio (NLR) – calculated by dividing your absolute neutrophil count by your absolute lymphocyte count – is a marker of systemic inflammation and immune balance. A 2018 study in Aging and Disease found that NLR above 3.0 was associated with significantly higher all-cause mortality in adults over 60 (Song et al., 2018). Optimal is below 2.0.

Red cell distribution width (RDW) – a measure of how much variation exists in the size of your red blood cells – has emerged as an independent predictor of mortality across multiple large cohort studies. Higher RDW indicates greater variability, which can signal inflammation, nutritional deficiency (iron, B12, folate), or impaired red blood cell production. A meta-analysis found that elevated RDW was associated with significantly increased all-cause mortality (Lippi et al., 2019).

If NLR or RDW is high: NLR elevation suggests systemic inflammation – investigate root causes (chronic infection, autoimmune activity, poor sleep, obesity). RDW elevation warrants investigation of nutritional status (iron, B12, folate), chronic inflammation, or bone marrow health.

Key Takeaway: Tier 1 biomarkers (hsCRP, fasting glucose, HbA1c, fasting insulin, ApoB, lipid panel) are available at any standard lab for under $200 and provide the foundation for all longevity tracking. Optimize these first before investing in expensive specialty tests. Target ranges: hsCRP below 0.5, fasting glucose 70-90, HbA1c below 5.2, fasting insulin 2-6, ApoB below 80.

Tier 2: Longevity-Specific Biomarkers (Moderate Cost, Highly Informative)

These markers aren't on standard panels, but they're available through most commercial labs with either a doctor's order or a direct-to-consumer testing service. They cost $30-100 per marker and reveal aging-specific patterns that Tier 1 tests miss.

Homocysteine

What it measures: Homocysteine is an amino acid produced as a byproduct of methylation (a critical biochemical process where methyl groups are added to DNA, proteins, and other molecules – essential for gene expression, detoxification, neurotransmitter production, and DNA repair). When methylation is functioning well, homocysteine is rapidly recycled back into methionine (using B12 and folate) or converted to cysteine (using B6). When methylation is impaired, homocysteine accumulates.

Why it matters: Elevated homocysteine directly damages endothelial cells, promotes oxidative stress (an imbalance between the production of reactive oxygen species and your body's ability to neutralize them – a key driver of cellular aging), increases blood clot formation, and impairs nitric oxide production (the molecule that relaxes blood vessels and maintains healthy blood pressure). A 2017 meta-analysis in Scientific Reports found that each 5 μmol/L increase in homocysteine was associated with a significant increase in all-cause mortality (Fan et al., 2017).

Homocysteine is also a proxy marker for methylation capacity. If yours is elevated, your body's methylation cycle isn't running efficiently – which affects DNA repair, detoxification, neurotransmitter synthesis, and epigenetic regulation.

If yours is high: B vitamins are the primary intervention. Methylfolate (5-MTHF, 400-800 mcg/day), methylcobalamin (B12, 1000 mcg/day), and pyridoxal-5'-phosphate (active B6, 25-50mg/day) directly support the enzymes that clear homocysteine. TMG (trimethylglycine, also called betaine – a methyl donor that provides an alternative pathway for recycling homocysteine) at 500-1000mg/day provides additional methyl groups through an alternate pathway. Riboflavin (B2, 25-50mg/day) supports the MTHFR enzyme (methylenetetrahydrofolate reductase – the enzyme that activates folate; roughly 40% of the population carries genetic variants that reduce its activity). NMN supplementation may also indirectly support methylation through improved NAD+-dependent enzyme function.

Omega-3 Index

What it measures: The omega-3 index measures the percentage of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in your red blood cell membranes – the two marine omega-3 fatty acids with the strongest evidence for longevity benefits. Unlike a serum omega-3 level (which fluctuates based on recent meals), the red blood cell membrane test reflects your omega-3 status over the past 90-120 days.

Why it matters: A 2021 study published in The American Journal of Clinical Nutrition analyzed data from 17 prospective cohort studies (42,466 individuals) and found that those with an omega-3 index above 8% had a 34% lower risk of death from any cause compared to those with an index below 4% – a risk reduction comparable to the difference between smokers and non-smokers (Harris et al., 2021).

The average American omega-3 index is approximately 4-5% – squarely in the highest-risk category. In Japan, where fish consumption is high, the average is 8-10%.

If yours is low: Consume fatty fish (salmon, sardines, mackerel, anchovies) 3-4 times per week, or supplement with a high-quality fish oil or algal oil providing 2-3g of combined EPA + DHA daily. It takes approximately 3-4 months of consistent intake to meaningfully shift your omega-3 index. Retest after 4 months. Note: plant-based omega-3 (ALA from flaxseed, chia, walnuts) converts to EPA and DHA at only 5-10% efficiency, so it's not a reliable way to raise your index.

GGT (Gamma-Glutamyl Transferase)

What it measures: GGT is a liver enzyme involved in glutathione (your body's most abundant endogenous antioxidant – a tripeptide that neutralizes free radicals, recycles other antioxidants, and is essential for detoxification) metabolism. It transfers gamma-glutamyl groups to amino acids, helping regenerate intracellular glutathione. Elevated GGT indicates that your liver is working harder to maintain glutathione levels – a signal of oxidative stress and impaired detoxification.

Why it matters: GGT is a dramatically underappreciated biomarker. A large-scale analysis published in Atherosclerosis (2014) found that GGT in the upper quartile of "normal" was associated with a 45% increased risk of cardiovascular events and a 26% increased risk of all-cause mortality compared to the lowest quartile – all within the standard reference range (Kunutsor et al., 2014).

GGT reflects oxidative stress load before it manifests as overt liver disease. It's one of the earliest signals that your liver's detoxification capacity is being overwhelmed – by alcohol, environmental toxins, medications, or metabolic dysfunction.

If yours is high: Reduce or eliminate alcohol (even moderate consumption raises GGT). Increase glutathione precursors: NAC (N-acetyl cysteine, 600-1200mg/day) directly provides the rate-limiting substrate for glutathione synthesis. Glycine (3-5g/day) and alpha-lipoic acid (300-600mg/day) also support glutathione recycling. Cruciferous vegetables (broccoli, cauliflower, Brussels sprouts) upregulate phase II liver detoxification enzymes.

Uric Acid

What it measures: Uric acid is the end product of purine metabolism (the process of breaking down purines – molecules found in DNA, RNA, and certain foods like organ meats, beer, and shellfish). Your kidneys excrete it in urine.

Why it matters: Uric acid has a U-shaped relationship with mortality – both too high and too low are problematic. Elevated uric acid (hyperuricemia) is strongly associated with gout, kidney stones, hypertension, insulin resistance, and cardiovascular disease. It activates the NLRP3 inflammasome (a protein complex inside immune cells that triggers inflammatory cascades when activated by danger signals), driving systemic inflammation.

But very low uric acid is also concerning – uric acid acts as an antioxidant in the blood (it accounts for roughly 50% of the antioxidant capacity of human plasma), so levels below 3.0 mg/dL may indicate impaired antioxidant defense.

A 2019 study in Arthritis & Rheumatology found that the lowest all-cause mortality was observed in individuals with uric acid between 4.0 and 5.0 mg/dL (Li et al., 2019).

If yours is high: Reduce fructose intake (fructose metabolism uniquely drives uric acid production). Reduce alcohol, especially beer. Increase hydration. Tart cherry concentrate (1 oz/day) has been shown in clinical trials to modestly lower uric acid. Vitamin C (500-1000mg/day) promotes uric acid excretion. Quercetin (a plant flavonoid found in onions, apples, and berries – also a potent senolytic at higher doses) inhibits xanthine oxidase, the enzyme that produces uric acid.

DHEA-S (Dehydroepiandrosterone Sulfate)

What it measures: DHEA-S is the sulfated, stable form of DHEA – the most abundant steroid hormone in your body and the precursor to both testosterone and estrogen. Produced primarily by the adrenal glands, DHEA-S peaks in your late 20s and then declines approximately 2-3% per year. By age 70, levels are typically 20-30% of their peak.

Why it matters: DHEA-S decline is one of the most consistent hormonal markers of aging. Low DHEA-S is associated with increased cardiovascular mortality, impaired immune function, accelerated bone loss, reduced muscle mass, cognitive decline, and higher rates of depression. Multiple studies and meta-analyses have found that low DHEA-S levels are significantly associated with all-cause mortality in both men and women (Ohlsson et al., 2015).

If yours is low: Discuss DHEA supplementation (25-50mg/day for men, 10-25mg/day for women) with a knowledgeable physician. Resistance training and adequate sleep both support natural DHEA production. Chronic stress suppresses DHEA – stress management practices (meditation, adequate recovery) are relevant. Vitamin D sufficiency supports adrenal hormone production.

Thyroid Panel (TSH + Free T3 + Free T4)

What it measures: TSH (thyroid-stimulating hormone – a pituitary hormone that signals your thyroid gland to produce T4 and T3) is the standard screening test, but it doesn't tell the full story. Free T3 (triiodothyronine – the biologically active thyroid hormone that sets your metabolic rate) and Free T4 (thyroxine – the inactive "storage" form that must be converted to T3 in your tissues) are needed to understand actual thyroid hormone production and conversion.

Why it matters: Thyroid function directly regulates metabolic rate, mitochondrial function, body temperature, cognitive speed, and energy production. Subclinical hypothyroidism (TSH between 2.5-4.5 mIU/L with "normal" T3/T4) affects an estimated 5-10% of adults and is associated with fatigue, weight gain, cognitive dulling, elevated cholesterol, and impaired recovery from exercise.

Many longevity clinicians consider TSH above 2.0 mIU/L a signal worth investigating, even though labs flag it as normal up to 4.5 mIU/L. Additionally, poor T4-to-T3 conversion (visible as adequate T4 but low T3) is common in aging, chronic stress, and selenium deficiency – and it means your tissues aren't getting enough active thyroid hormone even if TSH looks "normal."

If yours is off: Ensure adequate iodine (150-300 mcg/day from diet or supplement), selenium (100-200 mcg/day – essential for the deiodinase enzymes that convert T4 to T3), and zinc (15-30mg/day). Address chronic stress, which suppresses TSH and impairs conversion. If TSH is significantly above 2.5 mIU/L or Free T3 is consistently below 3.0 pg/mL, work with an endocrinologist who understands optimal ranges rather than just "normal" ones.

Tier 3: Advanced Biomarkers (Expensive, Emerging, Best for Tracking)

These markers represent the frontier of longevity testing. They're more expensive ($150-600+ per test), less widely available, and some are still being validated for clinical utility. They're most useful for people who already have their Tier 1 and Tier 2 markers optimized and want to measure aging at a deeper level – or want to track the impact of a specific intervention over time.

GlycanAge

What it measures: GlycanAge analyzes the glycan patterns (complex sugar molecules attached to the surface of proteins) on your immunoglobulin G (IgG) antibodies. Glycan composition changes predictably with age and reflects the balance between pro-inflammatory and anti-inflammatory immune signaling.

Cost: Approximately $300-400 per test.

Why it matters: A 2023 study in Aging Cell found that GlycanAge was responsive to lifestyle interventions – showing measurable changes after just 6-12 weeks of dietary modification, exercise, or supplementation changes (Petrovic et al., 2023). This makes it one of the fastest-responding biological age measurements, useful for tracking whether a specific protocol is working.

Limitations: Still being validated in large cohort studies. Less extensively studied than epigenetic clocks. Currently available only through the GlycanAge platform.

Epigenetic Clocks (TruAge, DunedinPACE)

What they measure: Epigenetic clocks analyze DNA methylation (chemical modifications to your DNA that regulate gene expression and change predictably with aging) patterns at hundreds of specific sites on your genome. Algorithms trained on large datasets use these patterns to estimate your biological age – how old your body is at the molecular level, regardless of your calendar age.

Cost: $250-500 per test.

Key clocks:

• GrimAge2 – Trained to predict time-to-death. It produces a single "biological age" number. If you're 45 and your GrimAge is 38, your methylation patterns resemble someone 7 years younger. Extensively validated as a mortality predictor.
• DunedinPACE – Instead of estimating a biological age, DunedinPACE measures the pace of aging – how many years of biological aging you're accumulating per calendar year. A score of 1.0 means you're aging at exactly the expected rate. Below 1.0 means slower than average. Above 1.0 means faster. Published in Nature Aging (2022), DunedinPACE was shown to predict future mortality, disability, and disease onset independently of other risk factors (Belsky et al., 2022).

Why they matter: Epigenetic clocks are the closest thing we have to a "speedometer" for aging. They respond to interventions – caloric restriction, exercise, improved sleep, and certain supplements have all been shown to slow epigenetic aging in clinical and observational studies.

Limitations: Require a blood draw. Results can vary between tests (biological variation of approximately 1-2 years between draws). Best used for trend tracking over 6-12 month intervals rather than as a single snapshot. See our biological age testing guide and protocol for lowering biological age for a deeper dive.

NAD+ Levels

What it measures: NAD+ (nicotinamide adenine dinucleotide – a coenzyme found in every living cell that is essential for energy metabolism, DNA repair, sirtuin enzyme activation, and hundreds of other biochemical reactions) levels in whole blood. NAD+ is a central molecule in aging – it declines approximately 50% between ages 40 and 60, and this decline is associated with mitochondrial dysfunction, impaired DNA repair, and reduced sirtuin activity.

Cost: $100-250 per test. Available through specialized labs.

Why it matters: NMN and NR (nicotinamide riboside – another NAD+ precursor) supplementation are among the most popular longevity interventions. Testing your NAD+ levels before and after supplementation tells you whether the intervention is actually raising your levels – and by how much.

A 2023 clinical trial published in Nature Aging demonstrated that 600mg/day of NMN increased whole blood NAD+ levels by approximately 38% over 60 days in middle-aged adults (Yi et al., 2023). However, individual response varies substantially – some people see 50%+ increases while others see minimal change.

Limitations: NAD+ measurement methodology is still being standardized. Results can vary between labs and even between blood draw timing (NAD+ follows a circadian rhythm). Best used for pre/post comparison within the same lab using the same methodology.

Telomere Length

What it measures: Telomeres are the protective caps on the ends of your chromosomes – repetitive DNA sequences (TTAGGG, repeated thousands of times) that prevent chromosome degradation during cell division. Each time a cell divides, telomeres shorten slightly. When they become critically short, the cell either enters senescence (stops dividing) or undergoes apoptosis (programmed cell death).

Cost: $100-300 per test.

Why it matters: Shorter telomeres are associated with increased disease risk and mortality in large population studies. However, telomere length testing has significant limitations:

• High variability between tests – a single measurement has limited precision
• Slow to change – interventions that slow telomere shortening take years to show measurable effects
• Population-level predictor, not individual – knowing your telomeres are in the 25th percentile for your age tells you something about risk at the population level, but it's a noisy predictor for any individual

A 2022 review in Aging Research Reviews concluded that while telomere length has prognostic value in large studies, it has "limited clinical utility for individual patients at this time" compared to epigenetic clocks (Vaiserman & Krasnienkov, 2022).

Bottom line: Test once for curiosity. Don't retest frequently – the variation between measurements is often larger than actual biological changes over 6-12 months. Epigenetic clocks are a better tool for tracking aging speed.

Inflammatory Cytokines (IL-6, TNF-alpha)

What they measure: Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) are pro-inflammatory cytokines – signaling proteins produced by immune cells that amplify inflammatory cascades. While hsCRP (Tier 1) is a downstream marker of inflammation, IL-6 and TNF-alpha are upstream drivers – they cause the inflammation that CRP reflects.

Cost: $75-200 per marker.

Why they matter: IL-6 is one of the most studied cytokines in aging. It's a central component of the senescence-associated secretory phenotype (SASP – the cocktail of inflammatory molecules that senescent cells release, damaging neighboring healthy tissue). Elevated IL-6 is independently associated with accelerated aging, muscle wasting, cognitive decline, and increased mortality risk.

A 2014 meta-analysis in Aging Cell found that centenarians consistently have lower IL-6 and TNF-alpha levels compared to age-matched controls who didn't reach extreme old age (Arai et al., 2015).

If they're high: The same anti-inflammatory strategies that lower hsCRP will reduce these cytokines: omega-3 fatty acids, curcumin, regular exercise, adequate sleep, and stress management. Fisetin (a plant flavonoid with senolytic properties – meaning it selectively destroys senescent cells, which are a major source of IL-6 and TNF-alpha) has been shown to reduce SASP factors in preclinical studies and is being evaluated in human trials.

Key Takeaway: Tier 2 markers — NAD+ metabolites, homocysteine, DHEA-S, GDF-15, and vitamin D — provide aging-specific information that Tier 1 cannot. NAD+ testing directly validates whether your NMN supplementation is working. Homocysteine tracks methylation status. GDF-15 is one of the strongest aging biomarkers emerging from epigenetic clock research.

How Supplements Affect These Markers

This is not medical advice – it's a summary of what clinical and preclinical research has shown about supplement effects on specific biomarkers:

Important context: Supplement effects on biomarkers vary significantly by individual. Genetics, baseline status, diet, medication interactions, and lifestyle all modulate the response. The only way to know if a supplement is working for you is to test before you start and retest 3-6 months later.

Testing Frequency: How Often Should You Retest?

Not all biomarkers change at the same speed. Testing too frequently wastes money; testing too infrequently means you're flying blind.

Pro tip: Group your tests into a single blood draw when possible. Most commercial labs can run 15-20 markers from a single tube collection. This saves time, reduces cost, and ensures all markers are measured under the same conditions (fasting state, time of day, hydration level).

How to Get These Tests

You have several options, depending on your situation:

Through Your Doctor

Ask specifically for the markers you want. Many doctors will order ApoB, fasting insulin, homocysteine, and vitamin D if you request them – they're just not included by default. Bring a list. Some doctors will push back on "unnecessary" testing – if yours does, consider the alternatives below.

What insurance typically covers: CBC, basic metabolic panel, standard lipid panel, HbA1c, TSH, vitamin D. You may need to self-pay for ApoB, fasting insulin, homocysteine, and omega-3 index.

Direct-to-Consumer Lab Services

A growing category of services allows you to order blood tests without a doctor's order. You select the tests online, visit a local lab (often the same Quest or Labcorp locations your doctor would use), get your blood drawn, and receive results electronically – usually within 3-5 business days.

These services typically offer individual tests ($15-60 each) and bundled panels ($100-400 for comprehensive longevity panels). Some include physician interpretation; others provide raw data for you to review.

What to look for: Services that use CLIA-certified labs (the federal standard for lab accuracy), offer the specific markers listed in this guide (especially ApoB, fasting insulin, and omega-3 index), and provide clear reference ranges alongside your results.

Specialized Longevity Panels

Some companies offer pre-built panels specifically designed for longevity optimization – combining blood biomarkers with algorithmic interpretation, trend tracking, and personalized recommendations. These tend to cost $200-500 per panel and include 30-60+ biomarkers in a single draw.

The advantage is convenience and interpretation. The disadvantage is cost and the fact that recommendations are often generic rather than personalized to your specific context.

At-Home Testing

Finger-prick at-home tests exist for some markers (omega-3 index, HbA1c, vitamin D, some lipid markers). They're convenient but generally less accurate than venous blood draws, especially for markers that require precise quantification (like fasting insulin or ApoB). Use at-home tests for rough screening; use lab blood draws for precision tracking.

Building Your Baseline: A Step-by-Step Approach

If you're starting from zero, here's how to build your longevity biomarker baseline without spending $2,000 on day one:

Step 1: Start with Tier 1 ($100-200)

Order: fasting glucose, HbA1c, fasting insulin (calculate HOMA-IR yourself), hsCRP, full lipid panel with ApoB, vitamin D (25-OH), and CBC with differential. This single draw gives you metabolic health, inflammation, cardiovascular risk, immune function, and vitamin D status.

Fasting protocol: 12-14 hour fast before the draw. Water only. Morning draw (before 10am) for most consistent results. Avoid strenuous exercise the day before (it can transiently elevate hsCRP and liver enzymes).

Step 2: Add Tier 2 Within 3-6 Months ($150-300)

Add: homocysteine, omega-3 index, GGT, uric acid, DHEA-S, and full thyroid panel (TSH, Free T3, Free T4). These can often be added to the same draw as your Tier 1 retest.

Step 3: Consider Tier 3 After Optimizing Tiers 1 and 2

Epigenetic clock testing (TruAge or similar) and GlycanAge make the most sense once you've optimized your actionable biomarkers – they give you a composite "score" to track over time. NAD+ testing is most useful as a pre/post measurement around starting an NAD+ precursor supplement.

Step 4: Track Trends, Not Snapshots

A single blood draw is a snapshot. Longevity is about trajectories. Your fasting insulin trending from 12 down to 5 over 18 months tells a much more compelling story than a single reading. Build a simple spreadsheet or use a tracking service to log every result with dates. Look for trends across 3+ data points.

Frequently Asked Questions

Related Reading

• Biological Age Testing: The Complete Guide to Measuring How Fast You're Aging
• How to Actually Lower Your Biological Age: A Practical Protocol
• NAD+ Decline by Age: The Complete Decade-by-Decade Timeline
• Inflammaging: The Chronic Inflammation That Drives Every Aging Hallmark
• Vitamin D and Aging: The Hormone Everyone Is Deficient In
• Omega-3 and Longevity: Beyond Heart Health
• Grip Strength and Mortality: The Cheapest Longevity Test You Can Do

This article is for educational purposes only and does not constitute medical advice. Blood biomarker optimization should be pursued in consultation with a qualified healthcare provider, particularly when results are significantly outside reference ranges or when considering pharmacological interventions.

Your blood tells a story about how fast you're aging – but only if you know which chapters to read. The standard annual physical checks for disease. A longevity blood panel checks for trajectory. Start with Tier 1, build your baseline, track your trends, and let the data guide your decisions.

The information is in your blood. You just have to ask for it.