Longevity blood test: which biomarkers are worth measuring?

A longevity blood test is a blood panel that measures values related to cardiovascular health, metabolism, inflammation and nutritional status. The idea is simple: if you want to invest in healthy ageing, you want to know where you stand. But not every biomarker is equally useful, and a result only means something in the right context.

On this page you will learn which blood values are well supported, which are mainly of research interest, how homocysteine relates to methylation and TMG, and how to read a result sensibly. This page is part of our central guide to supplements for healthy ageing.

What is a longevity blood test?

There is no standard medical test called “longevity”. Providers put together their own panel, often with twenty to eighty values. In the United States, companies such as Function Health have grown large with this model, and in the Netherlands and Belgium too you can have blood drawn at various labs without a referral.

The difference with a regular GP check-up is mainly breadth and purpose. A GP looks for an explanation of symptoms or monitors a known condition. A longevity blood test looks preventively at risk factors, often in people without symptoms. That can be valuable, but it carries a risk: the more values you measure, the greater the chance of an abnormality that turns out to mean nothing.

Which biomarkers are best supported?

The values below have a strong relationship with hard outcomes such as cardiovascular disease and diabetes, and clear reference values exist.

1. ApoB and LDL cholesterol

LDL cholesterol is the best-known risk factor for atherosclerosis. ApoB measures the number of particles carrying cholesterol and is considered by many researchers to be a more precise measure. Both are strongly linked to cardiovascular risk, and both can be influenced by diet, exercise and, if needed, medication.

2. Lipoprotein(a)

Lp(a) is largely genetically determined and barely changes with lifestyle. An elevated level increases cardiovascular risk. Because the value is stable, measuring Lp(a) once in your life is usually enough. International guidelines, such as those of the European Atherosclerosis Society, recommend this too.

3. HbA1c and fasting glucose

HbA1c gives an average of your blood sugar over about three months. Together with fasting glucose, it shows whether your glucose metabolism is moving towards prediabetes or diabetes. This is one of the most useful values in a longevity blood test, because insulin resistance often goes unnoticed for years.

4. Kidney and liver values

eGFR (an estimate of kidney function) and liver enzymes such as ALT and gamma-GT are standard parts of an extended blood panel. They are also relevant if you take supplements, because the liver and kidneys process many substances.

5. hs-CRP

High-sensitivity CRP measures low-grade inflammation. A slightly elevated value is associated with higher cardiovascular risk, but CRP also rises temporarily with a cold or after hard training. A single measurement therefore says little.

Homocysteine: the bridge to methylation

Homocysteine is an amino acid formed when methionine is broken down. Your body recycles it via two routes: with the help of folate and vitamin B12, and via the enzyme BHMT, where betaine (TMG) donates a methyl group. Vitamin B6 is needed for a third route, the breakdown to cysteine.

In observational research, elevated homocysteine is associated with cardiovascular disease and cognitive decline. Whether lowering it also reduces those risks has not been convincingly shown for cardiovascular disease in large trials. The value is mainly useful as a signal of your B-vitamin status and methylation.

Want to know what research says about betaine and homocysteine? Read our page on TMG research. A comparison of all compounds involved in methylation can be found under supplements for methylation.

Nutritional status: vitamin D, B12, folate and ferritin

These values say less about your long-term risk and more about deficiencies that are relatively easy to correct.

• Vitamin D (25-OH-D): deficiencies are common in Northern Europe, especially in winter.
• Vitamin B12: relevant with a plant-based diet, in older adults and when using acid reducers or metformin.
• Folate: together with B12, important for converting homocysteine.
• Ferritin: reflects your iron stores; both a value that is too low and one that is too high matter.

Which tests are not (yet) useful?

Part of what is offered in a longevity blood test is scientifically interesting but not yet suitable for basing personal decisions on.

NAD⁺ test

Tests are available that measure NAD⁺ in blood, for example with a finger prick. The problem: blood values say little about NAD⁺ in muscle, brain or liver, and there are no validated reference values. A 2026 study also found no clear age-related decline of NAD⁺ in whole blood. More background can be found on our page about longevity at the cellular level.

Biological age and epigenetic clocks

Epigenetic clocks estimate your biological age based on DNA methylation. They are valuable in research, but results can differ between tests and even between measurements. A lower biological age after a few months of supplement use is therefore not reliable proof that something works.

Overview: what to measure and why

Biomarker	Tells you about	Evidence	How often
ApoB / LDL	Cardiovascular risk	Strong	Every 1–5 years
Lp(a)	Inherited cardiovascular risk	Strong	Once
HbA1c / glucose	Glucose metabolism	Strong	Every 1–3 years
eGFR, liver enzymes	Kidney and liver function	Strong	Every 1–3 years
hs-CRP	Low-grade inflammation	Moderate	Repeat if in doubt
Homocysteine	B-vitamin status, methylation	Moderate	When at risk or supplementing
Vitamin D, B12, folate	Nutritional status	Good for deficiencies	When at risk
NAD+, biological age	Research purposes	Limited	Not needed

How do you read a longevity blood test result?

A few rules of thumb prevent unnecessary worry and wrong conclusions:

1. Look at trends, not a single measurement. Many values fluctuate with diet, sleep, training or an infection.
2. Distinguish reference values from “optimal” values. Some providers use stricter limits than medical guidelines. That can make sense, but it is not always evidence-based.
3. Discuss abnormalities with a doctor. Especially for kidney, liver or glucose values, medical assessment is needed.
4. Don’t expect miracles from supplements. Lifestyle and, where needed, medication have a much larger effect on most markers.

What does a longevity blood test cost and where can you get one?

In the Netherlands and Belgium you can go to various private labs and online providers without a referral. A basic panel with cholesterol, glucose, kidney and liver values is relatively affordable; extended panels with ApoB, Lp(a), homocysteine and vitamins cost more. Compare exactly which values are included and whether a doctor reviews abnormal results.

Do you use supplements such as NMN or TMG? Then it can be useful to measure homocysteine before starting and after a few months, so you can see whether anything changes. Want a realistic picture of what longevity supplements can do? See our longevity supplements ranked by evidence.

Frequently asked questions about the longevity blood test

What is a longevity blood test?

A panel of blood values that looks preventively at risk factors for cardiovascular disease, diabetes and deficiencies. It is not an official medical test and the content varies by provider.

Which blood values matter most?

ApoB or LDL cholesterol, Lp(a), HbA1c, fasting glucose, and kidney and liver values. Homocysteine, vitamin D and B12 are useful for your nutritional status.

Can I get an Lp(a) test without a doctor?

Yes, various private labs measure Lp(a) without a referral. Because the value is largely inherited, one measurement is usually enough. Discuss an elevated result with your GP.

Is an NAD+ test useful?

Not yet for personal decisions. Blood levels of NAD⁺ say little about NAD⁺ in tissues, and there are no validated reference values.

How often should I do a longevity blood test?

For most people without symptoms, an extended test every one to three years is enough, with Lp(a) once. With abnormalities or changes in lifestyle or supplementation, measuring more often can make sense.

Conclusion

A longevity blood test can help you spot risk factors early, provided you measure what matters: ApoB, Lp(a), HbA1c, kidney and liver function, supplemented by homocysteine and vitamins. Tests for NAD⁺ or biological age are interesting for research but not yet suitable for decisions. Read results as trends and discuss abnormalities with a doctor.

Sources

• Kronenberg F, et al. Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement. European Heart Journal, 2022.
• Smith AD, Refsum H. Homocysteine – from disease biomarker to disease prevention. Journal of Internal Medicine, 2021.
• Olthof MR, et al. Low dose betaine supplementation leads to immediate and long term lowering of plasma homocysteine in healthy men and women. Journal of Nutrition, 2003.
• López-Otín C, et al. Hallmarks of aging: an expanding universe. Cell, 2023.

This information is for general education and does not replace medical advice.