Why You Need a Biological Age Blood Test

By InsideTracker, August 3, 2023

Woman getting her blood drawn at home with an image of her InsideTracker InnerAgeAre you a grandparent trying to keep up and wrangle little ones? Or are you working crazy hours, striving for that promotion? We’re all trying to get more life out of each passing year and have enough gusto to continue our favorite pastimes and pick up new ones with life changes. But aging catches up with people at different rates. Habits and circumstances can lead to the discrepancy between your chronological and biological age. And the number of birthdays you’ve had (your chronological age) isn’t necessarily a reflection of your internal (biological) age. 

Biological age calculators are growing in popularity, offering you a way to quantify how aging is impacting you. InnerAge 2.0 is InsideTracker’s biological age calculator that uses blood biomarkers and biometric data to give you an estimate of your body’s true, internal age. 

Let’s dive into what you should know about biological age blood tests and how they compare to other commercially available aging clocks. 


Banner linking to InsideTracker courses


A blood test can estimate biological aging

Blood biomarkers are affected by lifestyle factors including food choices, exercise, sleep patterns, stress levels, and recovery. Blood analysis can measure biomarkers correlated with aging and disease, and can be used to compute an overall score for your biological age. Founder and Chief Scientific Officer of InsideTracker Dr. Gil Blander believes, “blood analysis aging tests are the best measure of biological age that we have so far.” 

Knowing your true biological age is a great motivator and catalyst for beneficial health changes. Since blood biomarkers are impacted by lifestyle habits, blood testing helps pinpoint the actions you need to take to improve your health. Even if you feel healthy now, crucial markers of healthy aging can start to go downhill even in the absence of physical symptoms. Dr. Blander weighs in on the insights gained from biological age tests stating, “they provide us with tools and actions to improve how we age.” Getting your biological age tested allows you to intervene proactively to optimize your healthspan

InsideTracker’s InnerAge 2.0 uses blood biomarkers to estimate your biological age. InsideTracker’s team of data scientists identified biomarkers that are most strongly correlated to aging and used them to design an algorithm to calculate your InnerAge and provide interventions for how to lower it.

Certain biomarkers are more strongly correlated with aging than others, and the contribution of each biomarker to your biological age is dependent on this correlation. For example, blood glucose and GGT (a liver enzyme) are both included in the InnerAge 2.0 calculation. However, InsideTracker’s data set showed that glucose is more strongly correlated with age than GGT, so it’s assigned a higher weight in your biological age score.


Blood biomarkers linked to aging 

Utilizing a blood test to determine your biological age is useful to set a baseline for how you are aging. Biomarkers that are typically included in a biological age blood test include metabolic health markers (glucose, LDL cholesterol, and triglycerides), sex hormones (testosterone, SHBG, and DHEAS), liver health markers (GGT), and immune markers (white blood cells).


Metabolism is the way the body utilizes calories from food to produce the energy required to maintain all necessary bodily functions, from breathing to digestion. To be ‘metabolically healthy’ means your body can respond to inputs (like food) and outputs (like exercise) in a positive way. Relevant biomarkers related to metabolic health that correlate to aging include:

  • Glucose: Glucose is the body’s primary source of fuel. Well-regulated glucose levels are essential to maintain a healthy metabolism. Cellular changes that happen as we age decrease glucose tolerance, resulting in elevated blood glucose levels. Therefore, higher glucose levels are associated with older age.
  • Hemoglobin A1c (HbA1c): HbA1c represents average blood glucose levels over the past 90-120 days. This measure provides insight on the macro level (a couple of months) while blood glucose provides insight on the micro level (less than 24 hours). Optimized HbA1c levels are associated with increased longevity.
  • Low-density lipoprotein (LDL): LDL particles carry cholesterol throughout the body, and high levels are associated with poorer health outcomes, especially cardiovascular health. LDL levels tend to rise as you age. However, LDL levels are also heavily influenced by lifestyle factors, so aging doesn’t mean achieving optimal LDL levels is unattainable. 
  • Triglycerides: Triglycerides are found in your blood and are the primary storage form of fat in the body. During long periods of fasting, triglycerides can be broken down and used for energy. Elevated levels of triglycerides are linked to several age-related diseases, so maintaining optimal levels of triglycerides is associated with lower biological age. 

Sex hormones

Aging is associated with changes in sex hormones. These changes include lower free testosterone, higher sex hormone binding globulin (SHBG), and lower DHEAS. Unoptimized levels of these biomarkers can lead to muscle loss, decreased functional performance, and muscle weakness. Here’s how these biomarkers work specifically to contribute to aging:

  • Free testosterone (males only): Free testosterone is the unbound testosterone available for your body to use. An optimal amount of free testosterone is important for muscle building, strength, and preventing age-related bone loss, so lower levels of free testosterone are associated with a higher biological age. 
  • Sex hormone binding globulin (males only): SHBG is a protein that binds to and transports sex hormones, including testosterone. Excessively high levels of SHBG reduce the amount of free, active testosterone available, so optimizing SHBG can increase the availability of testosterone in the body. This benefits bone health, sexual function, and heart health, while keeping biological age low. 
  • DHEAS (females only): DHEAS is a sex hormone produced by the adrenal cortex and is used to make other sex steroid hormones like estradiol and testosterone. DHEAS levels increase from childhood to around 20-30 years of age, then steadily decline after. Optimized levels of DHEAS help maintain energy levels, bone and muscle health, the immune system, and sexual function.

Immune and liver markers

Immune markers, specifically those involved in the inflammatory response, can increase with age. Relevant immune and liver markers that impact age include: 
  • Lymphocytes are a type of white blood cell activated in response to immune system stress. A lower lymphocyte count and lymphocyte percentage are associated with older age. 
  • GGT is a liver enzyme and an indicator of liver health, as it plays an essential role in how the liver breaks down toxins. GGT tends to increase with age, and optimized GGT helps to improve energy, endurance, and digestive health.


What are the benefits of blood analysis compared to other biological age tests? 

Blood is abundant with informative substances such as cells, nutrients, enzymes, hormones, and proteins, all known as blood biomarkers. And there are many reasons why blood analysis is a preferred method for calculating biological age:

  • It’s repeatable and reliable
  • It has a strong response to lifestyle factors
  • It allows you to find trends in your health status

Other types of biological aging tests 

Measuring telomere length and using methylation (or epigenetic clocks) to estimate biological age are becoming increasingly common. But the insights these tests provide may not be as insightful or actionable as you think. 

Telomere testing 

Telomeres are the caps at the end of your chromosomes that protect your DNA from getting damaged. Telomere length tends to decrease with age, and shorter telomeres are associated with a higher incidence of disease and lower survival. While telomere length is widely regarded as a good measure of biological age, accurate telomere testing is not widespread yet. Direct-to-consumer telomere tests prove to be highly variable and unactionable.

More research is needed before telomere testing can provide accurate biological age insights to the average consumer. 

Methylation clocks 

Epigenetics studies the way that our environment and behaviors impact how our genes work. One type of epigenetics, called DNA methylation, can determine which of our genes are switched on or off. Lifestyle and environmental factors can impact DNA methylation. For example, habits that are beneficial to your health such as getting enough sleep and eating fruits and vegetables can deactivate bad genes while activating good genes. 

Biological age calculations, like Hovarth’s Clock, are based on DNA methylation. There are a couple of downsides to DNA methylation calculations of biological age. Currently, the scores these tests provide aren’t easily modifiable with lifestyle changes, and they don’t account for known diseases that affect the aging process. Dr. Blander sees the current limitations, noting “in order to tie a particular lifestyle intervention to a reversal in methylation-based age, then interventional clinical trials are required, and we haven't seen too many of those yet.”

More research is needed before epigenetic clock estimations of biological aging are accurate and useful for consumers.


Who should get a biological age blood test?

“You should take a blood-based biological age test if you are motivated to make lifestyle changes and want to target signs of aging,” says Dr. Blander. Taking a biological age blood test provides beneficial insights for everyone, no matter what age or life stage you’re in. It allows you to make lifestyle changes needed to add years to your life and life to your years. You should take a biological age blood test if you want to:

  • Know how old you are internally, compared to your chronological age
  • Get an action plan with lifestyle changes to preserve your physical, biological, and cognitive health as you age 
  • Increase your healthspan so you can live healthier longer 

Measure and take steps to lower your biological age with InnerAge 2.0 

InnerAge 2.0 provides a complete understanding of your healthspan by revealing how well your body is currently working and how well it can work. The InnerAge algorithm compares each of your biomarkers to your peers in age and sex to calculate the distance between your values and the average, and applies a weighted contribution of each marker to your biological age score. InnerAge 2.0 calculation analyzes 17 biomarkers for males and 13 biomarkers for females related to cardiovascular and metabolic health, sex hormone balance, and liver function. The combination of these biomarkers gives you one overall biological age score and the algorithm allows you to see how each individual biomarker impacts your InnerAge. 

Any biomarkers that are higher or lower than optimal will affect your biological age, and will be displayed along with recommendations to optimize them and improve your InnerAge. This gives insight into your current health status and lets you take appropriate actions to increase your longevity and optimize your healthspan. Dr. Blander says, “blood biomarker tests [like InsideTracker’s InnerAge 2.0] provide the consumer with ways to improve their health, giving the power back to people to live healthier longer.”

Set your goal to InnerAge to see recommendations for improving your InnerAge-related biomarkers. Get an InnerAge 2.0 plan or add InnerAge 2.0 to the Ultimate Plan. How fast you age is not set in stone, so take steps today to preserve and optimize your physical and cognitive wellbeing.



[1] https://www.cdc.gov/hrqol/wellbeing.htm#three

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6292717/

[3] https://pubmed.ncbi.nlm.nih.gov/27146380/

[4] https://pubmed.ncbi.nlm.nih.gov/21521449/

[5] https://pubmed.ncbi.nlm.nih.gov/32967840/

[6] https://pubmed.ncbi.nlm.nih.gov/21215604/

[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC534923/

[8] https://pubmed.ncbi.nlm.nih.gov/31137992/

[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4399494/

[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356951/

[11] https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

[12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3703752/

[13] https://pubmed.ncbi.nlm.nih.gov/28864331/

[14] https://academic.oup.com/ajcn/article/114/3/1049/6195530?login=false

[15] https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf

8 Ways to Biohack Your Health

Free eBook


More on this topic

Are Epigenetic Clocks Ready to Determine Your Biological Age?
By Michelle Darian, MS, MPH, RD, December 29, 2022
What is InnerAge 2.0?
By Domenique Riedel, MS, December 14, 2022
New call-to-action