This is the first article in a two-part series on the best aging biomarkers to track for longevity. The second article will compare different tests and testing companies on the market and supply a sample testing schedule you can use.

“When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.”

—Lord Kelvin, May 3, 1883, Lecture on Electrical Units of Measurement

Homeslice Kelvin here is right.

If we, as spanners, want to advance past the level of “toddler-randomly-sticking-things-in-his-mouth-to-see-what-happens” in our quest for healthy human life extension, and if we want to be safe, rigorous, and scientific, we’ve got to be serious about measuring ourselves.

We can’t know how well we are aging, or how potentially helpful (or harmful) the life-extension interventions we attempt are, without measuring our baseline and then measuring the results of those interventions.

You may remember we’ve been using the last few weeks here at Longevity Advice to talk about self-measurement, or “quantified self.” So far we’ve had articles covering everything from how to measure your genetics (and why), to how to measure your sleep, your exercise, and even (for the ladies) your menstruation cycles. We’ve even got a handy, free 2,000+ word guide on five different biological health/vitality self-tests you can do from the comfort of your own home.

Now it’s time to get into slightly more advanced territory.

While most of the self-measurement areas we’ve covered are important for tracking healthy habits, or measuring some of the external results of those habits, none of them really gives us a picture of what exactly is happening inside our bodies as we age or become more (or less) healthy.

We need to get a more detailed picture.

We need to start tracking key health and aging biomarkers.

What are aging biomarkers and why track them?

Aging biomarkers, at the most basic level, are simply reliable indicators of someone’s biological age. There are obvious ones like gray hair and wrinkles, but also more subtle ones like grip strength, neuroplasticity, or (as we’ll cover below) things like blood albumin levels.

There are two crucial reasons why spanners need to track aging and longevity biomarkers:

1. To get a snapshot of your general health and see if there’s any possible problems you need to address right now, like hypertension, diabetes, or heightened risks for diseases like heart disease or dementia.
2. To track any positive or negative health effects of different longevity interventions over time (i.e. you’ll want to make sure you’re not doing yourself any harm with vitamin overdoses etc.).

Unfortunately, because the body is so complex, aging itself is difficult to self-track accurately. For example, there are at least nine different hallmarks of aging.

A recent PubMed search on “aging biomarkers” brings up 24,090 results.

And diving into any one of those papers turns up a vast array of different potential aging and longevity biomarkers, from DNA methylation, to gut microbiome composition, telomere length, inflammation levels, and blood levels of any number of different chemicals like hemoglobin or cholesterol.

From a practical (not to mention a financial) standpoint, any spanner trying to track all possible aging biomarkers is not going to have any time or energy left over to do anything else.

And from an efficiency standpoint, many biomarkers are not well-correlated with aging, or are measuring the same health impacts as other biomarkers, and so are duplicating the key information.

So how do you know which aging biomarkers are the most important to track for longevity and which only add marginal or no additional actionable information?

We need some sort of framework to use when choosing between biomarkers. Here’s what makes sense to me as a way to narrow down all the options:

1. Does the biomarker measure something demonstrably (through scientific studies) correlated to longevity/aging/mortality risk (or is it useful in combination with others to do so)?
2. Is that thing actionable (i.e. can you change it through intervention)?
3. Is this same thing measured easier/better by a different biomarker?
4. Is the biomarker already proven and used in clinical settings (i.e. in actual healthcare clinics, vs. just research or theoretical)?
5. Is the test for the biomarker relatively easy and inexpensive to obtain for non-doctors/scientists?

Using the above framework, I’ve combed through lots of different studies and recommendations from medical and scientific professionals to whittle down the list of possible biomarkers to what I think are the 20 best aging biomarkers to track for longevity.

Please note, while certain physiological biomarkers like grip strength or the frailty index are highly correlated with aging, we’ve already covered those tests in our guide to at-home biological age tests, so I haven’t included them here.

And don’t worry, while 20 different biomarkers may seem like a lot, you can get most of them from the same two or three different lab tests (nine of them, for instance, can be measured just with the standard “complete blood count test with differential” that your doctor orders for your annual physical while an additional four can all be tracked with a single genetic test).

The best aging biomarkers to track for longevity

I’ve broken the below top aging biomarkers into sections for disease prevention and for longevity intervention tracking, although there is significant overlap for what individual tests cover. 

Also, the suggestions below for how often to check/test individual biomarkers are not based on current clinical recommendations, since those are rarely frequent enough for spanners who are testing different longevity interventions on themselves every few months. Instead, I’ve used test frequency from different longevity clinical trials as a guide. For instance, in the famous TRIIM trial that showed a reversal of epigenetic aging in humans, study participants had their blood drawn around six times over a 12-month period, or on average every two months.

Best aging biomarkers for disease prevention

There are four main chronic diseases of aging that account for the most deaths from old age in the United States. They are atherosclerotic disease (heart disease and stroke), cancer, neurodegenerative disease (like Alzheimer’s and Parkinson’s), and chronic lower respiratory diseases (like emphysema and bronchitis).

For each of these age-related diseases, there are multiple different biomarkers you can track. The below aging biomarkers appear to be the most clinically useful.

1. LDL-P

LDL-P stands for “low-density lipoprotein particle number” and refers to the total amount of LDL particles in your blood.

• Why track it for longevity?: LDL-P is a greater predictor of cardiovascular disease risk than LDL-C since it measures, directly, the actual LDL particles present in your bloodstream rather than just measuring the cholesterol mass or calculating it with an equation. Because larger LDL particles may actually be protective, the smaller particles are what is really dangerous. For example, “In a large community-based sample, LDL-P was a more sensitive indicator of low CVD [cardiovascular disease] risk than either LDL-C or non-HDL-C.”
• How is it measured?: With a nuclear magnetic resonance (NMR) lipid profile test.
• What’s an optimal target range?: Under 1,000 nmol/L.
• How often should it be measured?: Every 3-6 months.
• Are there alternative biomarkers?: Apolipoprotein B (ApoB) measures much the same thing.

2. Ratio of triglyceride to HDL cholesterol

Also known as the “atherogenic index of plasma” this is basically just dividing your triglyceride level by your HDL cholesterol level.

• Why track it for longevity?: The triglyceride to HDL ratio is another way at getting at how many small/dense lipoprotein particles you have in your blood and has been shown to be predictive of all sorts of things related to longevity including all-cause mortality, stroke, insulin resistance (a marker for inflammation), and coronary heart disease.
• How is it measured?: By doing a standard serum lipid panel, and then by dividing the triglyceride level number (usually in mg/dL) by the HDL level number (also in mg/dL).
• What’s an optimal target range?: Ideally close to or less than 1.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: VLDL.

3. Lp(a)

Pronounced “Lp little a,” Lp(a) stands for “lipoprotein (a).” The LPA gene manufactures Lp(a) making levels in the body fairly constant over time.

• Why track it for longevity?: Lp(a) is an independent risk factor for atherosclerotic disease like stroke and heart attack, and people with certain LPA gene variants are at much greater risk for cardiovascular disease before the age of 50. Originally thought to not be modifiable, recent studies have shown lifestyle changes and medication can reduce the risk of death from Lp(a).
• How is it measured?: Either a lipoprotein (a) blood test or a genetic test like a whole-genome sequencing or genotyping test.
• What’s an optimal target range?: Less than 30 mg/dL.
• How often should it be measured?: Once to establish levels and annually afterward.
• Alternative biomarkers?: No.

4. Fasting glucose

Glucose is a sugar that our cells break down for energy. Fasting glucose measures the amount of glucose normally in your blood in-between meals.

• Why track it for longevity?: Blood glucose levels are important for detecting and predicting diseases like diabetes. Higher levels also predict stroke and heart attack, all-cause mortality, and even 28-day mortality for patients with COVID-19. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: Either a complete blood count test (CBC) with differential, an oral glucose tolerance test for more accurate results, or a continuous glucose monitor for the best data.
• What’s an optimal target range?: 65-99 mg/dL.
• How often should it be measured?: Every 3-6 months, or every day if you have a continuous glucose monitor.
• Alternative biomarkers?: HbA1c, Insulin.

5. C-reactive protein (CRP)

C-reactive protein is a protein secreted by the liver and rises in response to inflammation signals from immune cells, making it a reliable inflammation marker.

• Why track it for longevity?: Chronic inflammation is a major component of aging, leading to the term “inflammaging.” C-reactive protein levels can measure both chronic and acute inflammation. C-reactive protein levels are predictive of cardiovascular disease, cancer, and even the severity and lethality of COVID-19 infections. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A high sensitivity C-reactive protein test (hs-CRP).
• What’s an optimal target range?: Under 2.0 mg/L.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Homocysteine, oxidized LDL, oxidized phospholipid, fibrinogen, Lipoprotein-associated phospholipase A2 (LPPLA2).

6. Coronary artery calcium (CAC) score

This biomarker measures how much calcium has built up in the arteries around your heart. This number normally naturally increases with age.

• Why track it for longevity?: CAC score is primarily a way to gauge the biological “age” of your arteries, and is strongly predictive of cardiovascular disease risk. The negative effects of artery calcium may be reduced by interventions like aspirin and vitamin K.
• How is it measured?: A heart scan called a coronary calcium scan.
• What’s an optimal target range?: Varies by age, but ideally 0 Agatston units.
• How often should it be measured?: No more than once a year due to CT scan radiation.
• Alternative biomarkers?: No.

7. Insulin-like growth factor (IGF)

Insulin-like growth factor is a hormone produced in the liver that implements (“mediates” in medical-speak) the effects of growth hormone, telling cells in the body to grow.

• Why track it for longevity?: Aging scientists have long known total, unrestrained growth is bad for longevity, and several studies have shown lower IGF-1 levels lead to increased lifespan in animals like roundworms, fruit flies, and mice. That said, other studies have shown some level of growth is required for a functioning organism and IGF-1 levels that are too low aren’t great either. Think about it like a Goldilocks zone: keep your IGF-1 levels “just right” for maximum lifespan. High IGF-1 levels are associated with increased cancer risk, while too low levels of IGF-1 are associated with increased cardiovascular risk. 
• How is it measured?: An IGF-1 blood test. 
• What’s an optimal target range?: Varies by age and sex but for most adults it’s between 100-300 ng/mL.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Insulin-like growth factor-binding protein 3 (IGFBP-3).

8. BRCA1 and BRCA2 genes

BRCA stands for “BReast CAncer gene” and both the 1 and 2 versions usually produce proteins that help with DNA repair, but both versions also have harmful mutated variants.

• Why track it for longevity?: Certain variants of both the BRCA1 and BRCA2 genes can increase the risk of breast and ovarian (and other) cancers, and not just in women: breast and prostate cancer risk in men with these variants is also increased. Knowing if you have the harmful variant is important to know what lifestyle interventions to pursue to minimize cancer risk, and also to know if you need more frequent cancer screenings generally.
• How is it measured?: A genetic test like a whole-genome sequencing or genotyping test.
• What’s an optimal target range?: Having a non-mutated copy of each gene.
• How often should it be measured?: Just once.
• Alternative biomarkers?: No.

9. MSH2 and PMS1 genes

Both MSH2 and PMS1 are genes that usually repair DNA mismatches. Harmful mutations in these genes are associated with a disease called Lynch Syndrome.

• Why track it for longevity?: Lynch Syndrome significantly increases the risk for colorectal and stomach cancers before the age of 62. Knowing if you have the harmful variants is important to know what lifestyle interventions to pursue to minimize cancer risk, and also to know if you need more frequent cancer screenings generally.
• How is it measured?: A genetic test like a whole-genome sequencing or genotyping test.
• What’s an optimal target range?: Having a non-mutated copy of each gene.
• How often should it be measured?: Just once.
• Alternative biomarkers?: No.

10. APOE gene 

Normally a gene that encodes a protein for helping the body digest and metabolize different triglycerides and fatty acids, APOE can become mutated and lead to increased risk for various neurodegenerative diseases.

• Why track it for longevity?: APOE mutations are a big risk factor for diseases like Alzheimer’s and may even be a risk factor for atherosclerosis.
• How is it measured?: A genetic test like a whole-genome sequencing or genotyping test.
• What’s an optimal target range?: Having a non-mutated copy of the gene.
• How often should it be measured?: Just once.
• Alternative biomarkers?: No.

Best aging biomarkers for longevity intervention tracking

11. Alanine aminotransferase (ALT)

ALT is an enzyme usually found in liver and kidney cells that helps convert amino acids into energy for cells.

• Why track it for longevity?: Since the liver is crucial to processing all kinds of nutrients and molecules (including most of the ones spanners ingest through supplements), and breaking down potentially toxic substances, ensuring it’s healthy and functioning is crucial. When the liver is damaged, extra levels of ALT leak out into the blood. High ALT levels can be indicative of things like fatty liver disease, or of the presence of excessive toxins in the liver including drugs, supplements, or alcohol, and can also be predictive of mortality.
• How is it measured?: A blood test called an alanine aminotransferase (ALT) test. Often it is ordered as part of a standard liver panel or a comprehensive metabolic panel (CMP).
• What’s an optimal target range?: Under 20 units/L.
• How often should it be measured?: Every 3-6 months, or more frequently if taking potentially toxic supplements.
• Alternative biomarkers?: Aspartate aminotransferase (AST), uric acid, alkaline phosphatase, albumin.

12. Hormone levels of testosterone and estradiol

Testosterone and estradiol are sex hormones responsible for regulating everything from sperm creation, to the menstrual cycle, to muscle mass and bone density.

• Why track it for longevity?: Hormone levels are crucial for healthy aging, and low levels of testosterone predict higher all-cause mortality and cardiovascular disease risk, while low levels of estradiol can lead to weaker bones and more serious bone fractures in old age, as well as worse wound healing.
• How is it measured?: Either through an individual blood test (one for free testosterone, one for total testosterone, and one for estradiol), or through a more accurate urine test called the Dried Urine Test for Comprehensive Hormones (DUTCH) test.
• What’s an optimal target range?: 
• In men: estradiol: 10-82 pg/mL, total testosterone: 700-900 ng/dL, free testosterone: 150-244 pg/mL
• In women: estradiol: 15-350 pg/mL but varies by menstrual stage, total testosterone: 35-45 ng/dL, free testosterone:1.3-9.2 pg/mL
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Progesterone, estrogen, dehydroepiandrosterone (DHEA), sex hormone binding globulin (SHBG).

13. Serum albumin levels

Albumin is a protein produced in the liver that helps transport nutrients and enzymes through the blood and that also decreases with age.

• Why track it for longevity?: Albumin decreases with age, and low levels of albumin in the blood are associated with liver damage and with greater all-cause mortality. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: More than 45 g/L in men, more than 44 g/L in women.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: ALT, AST.

14. Serum creatinine

Creatinine is a waste byproduct of the muscles absorbing protein. It is usually filtered by the kidneys.

• Why track it for longevity?: Because creatinine is usually filtered out by the kidneys, high levels of it in the blood can indicate kidney damage, and indeed higher blood creatinine levels predict more bleeding complications from kidney biopsies. Creatinine increases with age, and increased creatinine is associated with greater risk of end-stage renal (kidney) disease and higher rates of mortality. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: 0.6-1.1 mg/dL.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Blood urea nitrogen (BUN).

15. Lymphocyte percent

Lymphocytes are types of white blood cells that help your body and immune system fight off infection.

• Why track it for longevity?: The functioning of the immune system is crucial as we age, its age-related failure is why old people are more susceptible to infections like the flu, or COVID-19. Lymphocyte percentage declines with age and lower levels are associated with higher all-cause mortality risk. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: 26-29%
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: White blood cell count, mean red cell volume (MCV), red cell distribution width (RDW).

16. Mean red cell volume (MCV)

Also called “mean corpuscular volume,” MCV is a measure of the average volume of a red blood cell, and this can change as blood cells become more or less filled with fluid.

• Why track it for longevity?: MCV increases with age, and is also associated with an increase in all-cause and liver cancer mortality. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: Under 92%.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Lymphocyte percent, red cell distribution width (RDW).

17. Red cell distribution width (RDW) percentage

Red cell distribution width percentage is the measure of how varied in size your red blood cells are (ideally you want them all pretty uniform in size).

• Why track it for longevity?: RDW percentage increases with age, and a higher RDW percentage is associated with higher all-cause mortality as well as higher cardiovascular disease risk. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: Under 12.5%.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Lymphocyte percent, mean red cell volume (MCV).

18. Alkaline phosphatase (ALP)

Alkaline phosphatase is an enzyme that primarily helps with metabolism and breaking down of compounds within the liver.

• Why track it for longevity?: Alkaline phosphatase increases with age. Higher levels correlate to a higher risk of death. It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: Under 48 U/L.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Albumin, ALT, AST.

19. White blood cell count

White blood cells (also called leukocytes) are the total number of immune cells in the body (lymphocytes, mentioned above, are a subset of white blood cells).

• Why track it for longevity?: White blood cells actually increase with age, as the body not only tries to fight infection but also starts accidentally targeting parts of itself for immune response. Higher numbers of white blood cells are thus associated with a greater risk of mortality (though so are too few, as your body still needs them for defense!). It’s also a key component if you want to measure your biological age using Morgan Levine’s phenotypic age calculator (which you can do by plugging your numbers in here or downloading Dr. Michael Lustgarten’s spreadsheet calculator).
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: 3,500-6,000 cells/mL.
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: Lymphocyte percent.

20. Vitamin D levels

Vitamin D, usually called “25-Hydroxyvitamin D” on lab reports, is an extremely important vitamin that helps out with everything from immune function, to bone health, to muscle growth.

• Why track it for longevity?: Higher vitamin D levels are associated with lower mortality (both cardiovascular and all-cause) in diabetics and have been shown to protect against acute respiratory tract infections like COVID-19. Higher vitamin D levels may also lower the risk of certain cancers.
• How is it measured?: A complete blood count test (CBC) with differential.
• What’s an optimal target range?: 40-60 ng/mL
• How often should it be measured?: Every 3-6 months.
• Alternative biomarkers?: No.

The 80/20: what 3 tests should I take to cover most of these biomarkers?

If you’ve been paying attention to the “How is it measured?” sections for each aging biomarker, you’ll see several of the same tests come up over and over again.

I think you can get about 80% of the benefit of biomarker tracking by just taking these three tests (two of which you likely already get from your doctor during your annual physical):

• Complete blood count test (CBC) with differential (4-6 times a year)
• Nuclear magnetic resonance (NMR) lipid profile test (this will get all your standard lipid panel stuff, plus the more accurate advanced stuff like LDL-P) (4-6 times a year)
• Whole-genome sequencing test (only needed one time ever)

After all my research I also personally intend to add on to the above list the following four lab tests from my doctor:

• A high sensitivity C-reactive protein test (hs-CRP) (for inflammation and to use in Morgan Levine’s phenotypic age calculator)
• A comprehensive metabolic panel (CMP) with ALT and AST (for liver function)
• An IGF-1 blood test (for dietary changes)
• A DUTCH test (for hormone levels)

Plus I’ll be looking into getting a continuous glucose monitor in the near future as well.

“But what about…?”

I know even with the excessive length of this piece there are tons of possible longevity biomarkers I left out, and those readers who are advanced spanners will, I’m sure, share them in the comments.

For instance, while I only covered 20 life-extension biomarkers, the Vitality in Aging longitudinal study is tracking around 75 different biomarkers.

But before you yell at me too much in the comments, let me tick off a couple aging biomarkers I purposely didn’t include here, with some explanation why.

First is telomere length which, despite all the hoopla around it when it was first discovered, is actually not a good predictor of mortality and longevity. According to a 2020 study on aging biomarkers, “Telomere length showed the weakest correlations with both chronological age and with the other measurements.”

And second, epigenetic clocks that measure DNA methylation are very exciting (and the most accurate ones show a higher correlation with all-cause mortality than even something like Levine’s phenotypic age clock), but they are so new most are not yet clinically proven, so I left them off this list.

However, we will be doing an entire article comparing all the different epigenetic and biological clocks on the market, next week! So hold on to your horses until then.

Other great lists of aging biomarkers

In my research, I came across several other helpful collections of recommended biomarkers to track for longevity, including from some prominent doctors, anti-aging researchers, and longevity experts. I’ve included a selection below so you can see how their recommendations differ (or don’t) from mine.

• Dr. Peter Attia recommends several different lab tests and biomarkers on his podcast.
• Dr. Michael Lustgarten covers the nine biomarkers of Levine’s phenotypic age calculator in detail in this video.
• Dr. Valter Longo lists off his top biomarkers in an interview with Dr. Rhonda Patrick.
• Dr. David Sinclair shows which biomarkers he’s tracking (using a company called InsideTracker) in this Instagram post.
• Longevity biohacker Ben Greenfield covers his top lab tests in this article.
• Health and fitness coach Jesse O’Brien lays out his favorite longevity biomarkers in this blog post.
• And for the MOST COMPREHENSIVE look at aging biomarkers, this 145-page report by the Aging Analytics Agency can’t be topped.