How old is your body, really? Biological age, explained

Published August 18, 2026

Your date of birth tells you how many years you’ve lived, but not how well your body is aging. While physical changes like gray hair, fine lines, and slower movements are visible reminders of time passing, they don’t fully reflect what’s happening beneath the surface. Biological age goes beyond just visible signs of aging to check a range of biomarkers to estimate how fast your body systems are aging, helping to paint a clearer picture of your overall wellness. You can add a Humanity Biological Age report to your purchase when you buy a Comprehensive Health Profile — Men's, Comprehensive Health Profile — Women's, Elite Health Profile, or Fitness Profile — Elite Test on questhealth.com.

How do scientists estimate biological age?

Scientists use large sets of data from research studies to find patterns that predict health risk.²

Cells and body tissues naturally wear down over time, but this happens faster in some people than others. Your genes, environment, and lifestyle all affect how fast your body ages.¹

Large research studies have followed hundreds of thousands of people across decades of their lives. The studies track information on blood tests, genetics, family histories, physical activity, diet, health conditions, and then eventual health outcomes. They look for correlations between these earlier factors and then future disease risk.² Effectively by looking at both the past and future of the participants in the studies, they can make models that can look at your present and make predictions about your future.

Tools that estimate biological age might use data from many sources. This includes lab tests, your health history, your family health history, lifestyle, and body measurements. Those measurements can be used in calculations based on what was learned in the research studies. See below how to find out your own biological age by adding a Humanity Biological Age Report to a compatible lab test.

The critical role of comprehensive and recurring lab testing

Lab tests are available to look at biomarkers linked to cell aging. These tests can form the basis for calculating your biological age. They measure key areas of your body including metabolic health, heart health, inflammation, and liver and kidney function. Lab testing may also be combined with questions about your health history, family health history, and lifestyle habits.

Metabolic health

• Hemoglobin A1c (HbA1c): Measures your average blood sugar over the past 3 months
• Fasting glucose: Measures blood sugar at a single point in time after fasting
• Fasting insulin: Estimates how much insulin your pancreas makes to manage blood sugar. An elevated fasting insulin may be an early sign of insulin resistance

Heart health

• Lipid markers: Checks total cholesterol, LDL, HDL, and triglycerides to measure fats in the blood
• Apolipoprotein B (ApoB): Measures a protein that carries harmful LDL cholesterol around the body

Inflammation

• High-sensitivity C-reactive protein (hs-CRP): Detects low, persistent levels of inflammation that may be associated with cardiovascular disease risk

Liver and kidney function

• Liver enzymes: Measures the enzymes ALT, AST, ALP, GGT that rise in response to inflammation or injury to liver cells
• Bilirubin: Measures this waste product made during the normal breakdown of red blood cells. The liver normally clears bilirubin, and testing helps understand liver function
• Albumin: Measures this protein made by the liver that helps nourish tissue
• Creatinine and blood urea nitrogen (BUN): Measures waste products that the kidneys filter out
• eGFR (estimated glomerular filtration rate): Helps estimate how well your kidneys remove toxins and excess fluid from the blood

What can you do with your biological age?

Data about your current health, lifestyle, and health history can be used to calculate a biological age. Your biological age may be higher, lower, or the same as your chronological age.

You can use this information to guide lifestyle changes. If you’re happy with your biological age, that can be a good sign that your current habits are working.

There’s no magic pill for slowing the aging process. But you can keep your biological clock ticking slower with healthy habits.¹,³,⁴

• Regular testing: Keeping to a regular schedule of lab testing and biological age reports may be an important part of keeping you heading in a healthy direction
• Sleep: Recent research suggests that getting 6 to 8 hours of sleep a night may lead to the slowest aging
• Eat healthy: Eat a balanced diet of fruits, vegetables, whole grains, healthy fats, and lean proteins
• Exercise daily: Movement helps you stay healthier longer with better functioning. Gym classes, chair yoga, walking the dog, washing dishes, playing with your kids, taking the stairs at work all adds up. Aim for moving throughout the day to get the recommended 3 to 6 hours of moderate physical activity a week
• Manage stress: Staying stressed out can speed up aging. Try meditation, therapy, yoga, or improved sleep habits to help reduce stress
• Quit smoking: Smoking harms your whole body and can speed up aging. Yet, your body starts to heal as soon as you quit. Quitting at any age can slow the clock

Your birthday may be fixed, but many of the factors that influence how your body ages are within your control. If you’re curious about what’s happening beneath the surface, health insights from lab testing can help you better understand your body and track changes over time.