Are Biological Age Tests Accurate? Here’s What Doctors Say

Anxiety about aging is so common that there’s a term for it now: FOGO, which stands for Fear Of Getting Old. In a Pfizer survey of over 2,088 American adults, 87% of participants reported having at least one fear about getting older. But there’s an important distinction to make between your chronological age and your biological age. Whether you’ve lived on this earth for 20, 30, or 40 years, your body might tell a very different story. That’s where biological age tests come in: they can assess your internal age at the cellular level to help you figure out what aspects of your health you need to work on in order to live a longer life. Pfizer’s survey revealed that most people aren’t actually afraid of dying: the majority of participants’ fears related to a decline in physical ability or memory, or developing chronic illness. But fret not — because many of these issues are actually preventable. And that’s the beauty of these biological age tests. They allow you to take a more proactive, preventative approach to your health — nipping any potential issues in the bud before they bloom into a more serious condition or disease. “The anti-aging industry is much more than vanity medicine, it truly is trying to figure out the key to longevity and aging gracefully,” explains Dr. Brynna Connor, MD, healthcare ambassador at NorthWestPharmacy.com. So, how does a biological age test work? Are these tests accurate? And should you take one? I talked to some medical experts — and even tried taking a test myself — to find out. Here’s what to know. RELATED: 10 Aging Myths We Should Stop Believing How Biological Age Tests Work Today, you can order a variety of different biological age tests online that will deliver right to your doorstep — but they don’t all work the same. Some tests examine patterns in DNA methylation. As you age, chemical tags attach to the DNA code, and the patterns of these tags can offer some insight into your biological age. Other tests look at the average length of telomeres, stretches of DNA that are found at the ends of chromosomes. Telomeres tend to shorten as you get older, says Dr. Greg Hammer, a former professor at Stanford University School of Medicine, pediatric intensive care physician, pediatric anesthesiologist, mindfulness expert, and author of GAIN Without Pain: The Happiness Handbook for Health Care Professionals. “Though telomere length gives a qualitative assessment of cellular aging, more specific and quantitative application may be a few years off,” he explains. Finally, other biological age tests rely on blood samples. “A blood test can provide insight into your biological age by measuring specific biomarkers that are indicative of cellular function and systemic health,” explains Dr. Farhan Malik, MD, owner and senior medical director for Prometheus. “By analyzing blood levels of things like albumin, creatinine, glucose, triglycerides, thyroid hormones, vitamin D, and inflammatory cytokines, the test can assess biological age compared to chronological age.” For example, Dr. Malik notes that a 50-year-old with robust vitamin D levels, stable blood sugar, healthy kidney and liver function, and markers of low inflammation may have a biological age of 40. On the other hand, a 50-year-old with insulin resistance, shrinking kidney function, low vitamin D, and increased inflammatory cytokines may show an older biological age of 60. “These biomarkers paint a picture of true physiological age by integrating information from many body systems,” he tells AskMen. “The blood test provides an objective measure to quantify health status beyond the number of years you've been alive.” Are Biological Age Tests Accurate? “I’m asked every day about biological age tests,” says Dr. Connor. She believes these tests can be very accurate — depending on the type and volume of data they take into account. “I've used these tests with patients to identify potential areas for intervention and track improvements with lifestyle, diet, or supplement changes intended to slow or reverse biological aging,” says Dr. Malik. “However, the aging process is highly complex and individualized. At best, the currently available commercial tests can provide a rough estimate of certain limited aspects of biological age.” Dr. Neil Paulvin advises using these tests as a guide rather than as gospel. “This is not an exact science,” he tells AskMen. In other words, these tests can’t tell you exactly how long you’ll live — but they can definitely be helpful. “As with any lab test, biological age results require careful interpretation alongside a holistic view of the individual,” adds Dr. Malik. “A qualified healthcare professional can contextualize the findings and recommend appropriate interventions or lifestyle modifications.” According to Dr. Hammer, these tests are also becoming more accurate over time. What Are the Benefits of Knowing Your Biological Age? “Biological age tests, which assess cellular markers of aging, can provide valuable insights into an individual's overall health status and longevity potential,” says Dr. Malik. “These tests are particularly relevant for individuals with a family history of age-related diseases or those concerned about accelerated aging due to lifestyle factors or environmental exposures.” For example, you may want to take a biological age test if you know both of your grandparents had Alzheimer’s, or you’re worried about how your current sedentary lifestyle or smoking habit may be impacting your health. According to Dr. Mert Erogul, MD, a board-certified emergency medicine physician at Maimonides Medical Center, biological age tests can also be useful for testing the value of a particular intervention. Say, for instance, you’re tyring a new diet, exercise routine, medication, or supplement. You could take the biological age test two to six months after you started it to see whether or not it’s benefitting your health. Dr. Hammer advises first considering what you hope to gain from taking a biological age test. Are you only taking the test because you’re curious about how slow or fast you’re aging? And regardless of your intention, are you capable of handling any anxiety that arises if your biological age is older than you thought?  Most importantly, are you willing to make changes to your diet, lifestyle, and other factors for the sake of reversing your biological age? These are some questions to ask yourself before investing in a biological age test. RELATED: Four Ways Your Body Changes After 30 What It’s Like to Take a Biological Age Test I have a family history of multiple diseases, and I’ve also been dealing with some unexplained health symptoms as of late — so I decided to take the Thorne Biological Age Test to gain some insight into the pace at which I’m aging, and which aspects of my health may be suffering.  Studies have shown that our organs age at different rates, and what I liked about the Thorne test is that they offer “age scores” in a number of different categories, including metabolic age, liver age, lipid age, kidney age, and blood age. Here’s what the test involves. First, I filled out my online health profile, answering questions about my lifestyle, diet, sleep and exercise habits, medical history, and health goals. I then made an appointment at my local Quest Diagnostics. Since a 12-hour fast is required before taking the test, I made an appointment in the morning.  The blood draw itself was super quick and easy — I was in and out of the office in two to three minutes flat. In just four days, I received an email that my results were ready to review in the online portal. Thorne uses machine learning to analyze biomarkers in your blood. In addition to providing my age scores in the report, the company also offers a detailed improvement plan with personalized diet, exercise, lifestyle, and supplement recommendations. I’ll admit, I was pretty shocked to find that I’m biologically older by a few years. I work out five days a week, avoid processed foods, generally get 7-8 hours of sleep a night, and eat a balanced diet with plenty of protein, whole grains, fruit, and vegetables. But before I went into a tailspin of existential dread and anxiety, I met with Dr. Nathan Price, Chief Scientific Officer at Thorne, to get a more in-depth analysis of my results. While talking with Dr. Price, I realized that there are a few factors at play here — fortunately, all of which are within my control. First, Dr. Price noted that one key reason I’m biologically older is that my Dehydroepiandrosterone (DHEA) hormone levels are quite low for my age. DHEA plays a crucial role in hormone regulation, and according to Dr. Price, it’s one of the strongest predictors for biological age “So, that’s a dominant element in determining your results,” he says. When I mentioned that I struggle with managing chronic stress, Dr. Price explained that can have a strong influence on driving DHEA levels down. “You can also see the effects of stress in the biomarkers relating to your immune system,” he adds, while pointing out that my white blood cell count is a bit low. In other words, it turns out that stress is, quite literally, aging me. The good news? There are things I can do about it. Dr. Price recommended that I start focusing on stress management practices, getting deep sleep, and seeking out adaptogen supplements, all of which may collectively help to boost my DHEA — thus reversing my biological age. Something to keep in mind: there is a degree of variability here, which is why Dr. Price recommends repeat testing. In my report, higher urea nitrogen levels resulted a higher biological kidney age. However, Dr. Price pointed out that dehydration can affect these results — and I barely drank any water at all the morning of my blood draw.  Additionally, Dr. Price says you’re more likely to have a higher urea nitrogen level if you have a particularly high protein diet, which is the case for me. That doesn’t mean eating higher amounts of protein is bad for you or your kidneys – but it is taxing on your kidneys to process protein, which explains the increased levels of urea nitrogen. Can You Reverse Your Body's Biological Age? If, like me, you’re dismayed to find that you’re biologically older — don’t stress. After all, biological age isn’t a fixed number. That’s the whole point of taking these tests — shedding light on potential areas for improvement and empowering you to do something about it. “Don't be too alarmed by a higher biological age result,” says Dr. Malik. “These tests only provide a snapshot in time and may not reflect changes over an individual's lifespan. While these tests offer clues, a person's overall health and vitality depend on a complex interplay of genetics, lifestyle, and social determinants of health. Biological age is best considered as one data point, rather than a definitive verdict on health status or longevity. Maintaining healthy behaviors and managing risk factors within your control remain the most evidence-based ways to support healthy aging.” According to Dr. Hammer, you may want to consider further testing if you’re concerned about your biological age. Ask your doctor about any specific areas of concern that were highlighted by your test results — such as hormone balance, liver health, or immune function. They may recommend additional tests to identify the root cause of the issue. And don’t be surprised if, after making concerted efforts to support your health, you find that your biological age decreases in a relatively short spam of time, says Dr. Erogul. For instance, a 2024 study found that following a plant-based fasting-mimicking diet for five days per month can reduce your biological age by 2.5 years after just three months. “The key is to focus on the long game — maintaining good sleep, nutrition, exercise, and stress management over the decades,” adds Dr. Malik. “That will have the biggest impact on your health and longevity. Biological age is not destiny. I've seen many people make small changes to improve their results over time through sustainable lifestyle habits.” You Might Also Dig: Science Confirms Some People Age Faster Than OthersHigh Levels of Exercise Linked To 9-Year Biological Age AdvantageAt-Home Wellness Kits That Bring the Doctor's Office to You