New Tests Measure Your Body’s Biological Age, Offering a Glimpse into the Future of Health Care
Matt Fuchs is the editor-in-chief of Leaps.org and Making Sense of Science. He is also a contributing reporter to the Washington Post and has written for the New York Times, Time Magazine, WIRED and the Washington Post Magazine, among other outlets. Follow him @fuchswriter.

A senior long jumper competes in the 80-84-year-old age division at the 2007 World Masters Championships Stadia (track and field competition) at Riccione Stadium in Riccione, Italy on September 6, 2007. From the book project Racing Age.
What if a simple blood test revealed how fast you're aging, and this meant more to you and your insurance company than the number of candles on your birthday cake?
The question of why individuals thrive or decline has loomed large in 2020, with COVID-19 harming people of all ages, while leaving others asymptomatic. Meanwhile, scientists have produced new measures, called aging clocks, that attempt to predict mortality and may eventually affect how we perceive aging.
Take, for example, "senior" athletes who perform more like 50-year-olds. But people over 65 are lumped into one category, whether they are winning marathons or using a walker. Meanwhile, I'm entering "middle age," a label just as vague. It's frustrating to have a better grasp on the lifecycle of my phone than my own body.
That could change soon, due to clock technology. In 2013, UCLA biostatistician Steven Horvath took a new approach to an old carnival trick, guessing people's ages by looking at epigenetics: how chemical compounds in our cells turn genetic instructions on or off. Exercise, pollutants, and other aspects of lifestyle and environment can flip these switches, converting a skin cell into a hair cell, for example. Then, hair may sprout from your ears.
Horvath's epigenetic clock approximated age within just a few years; an above-average estimate suggested fast aging. This "basically changed everything," said Vadim Gladyshev, a Harvard geneticist, leading to more epigenetic clocks and, just since May, additional clocks of the heart, products of cell metabolism, and microbes in a person's mouth and gut.
Machine learning is fueling these discoveries. Scientists send algorithms hunting through jungles of health data for factors related to physical demise. "Nothing in [the aging] industry has progressed as much as biomarkers," said Alex Zhavoronkov, CEO of Deep Longevity, a pioneer in learning-based clocks.
Researchers told LeapsMag that this tech could help identify age-related vulnerabilities to diseases—including COVID-19—and protective drugs.
Clocking disease vulnerability
In July, Yale researcher Morgan Levine found people were more likely to be hospitalized and die from COVID-19 if their aging clocks were ticking ahead of their calendar years. This effect held regardless of pre-existing conditions.
The study used Levine's biological aging clock, called PhenoAge, which is more accurate than previous versions. To develop it, she looked at data on health indices over several decades, focusing on nine hallmarks of aging—such as inflammation—that correspond to when people die. Then she used AI to find which epigenetic patterns in blood samples were strongly associated with physical aging. The PhenoAge clock reads these patterns to predict biological age; mortality goes up 62 percent among the fastest agers.
The cocktail, aimed at restoring immune function, reversed age by an average of 2.5 years, according to an epigenetic clock measurement taken before and after the intervention.
Because PhenoAge links chronic inflammation to aging and vulnerability, Levine proposed treating "inflammaging" to counter COVID-19.
Gladyshev reported similar findings, and Nir Barzilai, director of the Institute of Aging Research at Albert Einstein College of Medicine, agreed that biological age deserves greater focus. PhenoAge is an important innovation, he said, but most precise when measuring average age across large populations. Until clocks—including his blood protein version—account for differences in how individuals age, "Multi-morbidity is really the major biomarker" for a given person. Barzilai thinks individuals over 65 with two or more diseases are biologically older than their chronological age—about half the population in this study.
He believes COVID-19 efforts aren't taking stock of these differences. "The scientists are living in silos," he said, with many unaware aging has a biology that can be targeted.
The missed opportunities could be profound, especially for lower-income communities with disproportionately advanced aging. Barzilai has read eight different observational studies finding decreased COVID-19 severity among people taking metformin, the diabetes drug, which is believed to slow down the major hallmarks of biological aging, such as inflammation. Once a vaccine is identified, biologically older people could supplement it with metformin, but the medical establishment requires lengthy clinical trials. "The conservatism is taking over in days of war," Barzilai said.
Drug benefits on time
Clocks, once validated, could gauge drug effectiveness against age-related diseases quicker and cheaper than trials that track health outcomes over many years, expediting FDA approval of such therapies. For this to happen, though, the FDA must see evidence that rewinding clocks or improving related biomarkers leads to clinical benefits for patients. Researchers believe that clinical applications for at least some of these clocks are five to 10 years away.
Progress was made in last year's TRIIM trial, run by immunologist Gregory Fahy at Stanford Medical Center. People in their 50s took growth hormone, metformin and another diabetes drug, dehydroepiandrosterone, for 12 months. The cocktail, aimed at restoring immune function, reversed age by an average of 2.5 years, according to an epigenetic clock measurement taken before and after the intervention. Don't quit your gym just yet; TRIIM included just nine Caucasian men. A follow-up with 85 diverse participants begins next month.
But even group averages of epigenetic measures can be questionable, explained Willard Freeman, a researcher with the Reynolds Oklahoma Center on Aging. Consider this odd finding: heroin addicts tend to have younger epigenetic ages. "With the exception of Keith Richards, I don't think heroin is a great way to live a long healthy life," Freeman said.
Such confounders reveal that scientists—and AI—are still struggling to unearth the roots of aging. Do clocks simply reflect damage, mirrors to show who's the frailest of them all? Or do they programmatically drive aging? The answer involves vast complexity, like trying to deduce the direct causes of a 17-car pileup on a potholed road in foggy conditions. Except, instead of 17 cars, it's millions of epigenetic sites and thousands of potential genes, RNA molecules and blood proteins acting on aging and each other.
Because the various measures—epigenetics, microbes, etc.—capture distinct aging dimensions, an important goal is unifying them into one "mosaic of biological ages," as Levine called it. Gladyshev said more datasets are needed. Just yesterday, though, Zhavoronkov launched Deep Longevity's groundbreaking composite of metrics to consumers – something that was previously available only to clinicians. The iPhone app allows users to upload their own samples and tracks aging on multiple levels – epigenetic, behavioral, microbiome, and more. It even includes a deep psychological clock asking if people feel as old as they are. Perhaps Twain's adage about mind over matter is evidence-backed.
Zhavoronkov appeared youthful in our Zoom interview, but admitted self-testing shows an advanced age because "I do not sleep"; indeed, he'd scheduled me at midnight Hong Kong time. Perhaps explaining his insomnia, he fears economic collapse if age-related diseases cost the global economy over $30 trillion by 2030. Rather than seeking eternal life, researchers like Zhavoronkov aim to increase health span: fully living our final decades without excess pain and hospital bills.
It's also a lucrative sales pitch to 7.8 billion aging humans.
Get your bio age
Levine, the Yale scientist, has partnered with Elysium Health to sell Index, an epigenetic measure launched in late 2019, direct to consumers, using their saliva samples. Elysium will roll out additional measures as research progresses, starting with an assessment of how fast someone is accumulating cells that no longer divide. "The more measures to capture specific processes, the more we can actually understand what's unique for an individual," Levine said.
Another company, InsideTracker, with an advisory board headlined by Harvard's David Sinclair, eschews the quirkiness of epigenetics. Its new InnerAge 2.0 test, announced this month, analyzes 18 blood biomarkers associated with longevity.
"You can imagine payers clamoring to charge people for costs with a kind of personal responsibility to them."
Because aging isn't considered a disease, consumer aging tests don't require FDA approval, and some researchers are skeptical of their use in the near future. "I'm on the fence as to whether these things are ready to be rolled out," said Freeman, the Oklahoma researcher. "We need to do our traditional experimental study design to [be] confident they're actually useful."
Then, 50-year-olds who are biologically 45 may wait five years for their first colonoscopy, Barzilai said. Despite some forerunners, clinical applications for individuals are mostly prospective, yet I was intrigued. Could these clocks reveal if I'm following the footsteps of the super-agers? Or will I rack up the hospital bills of Zhavoronkov's nightmares?
I sent my blood for testing with InsideTracker. Fearing the worst—an InnerAge accelerated by a couple of decades—I asked thought leaders where this technology is headed.
Insurance 2030
With continued advances, by 2030 you'll learn your biological age with a glance at your wristwatch. You won't be the only monitor; your insurance company may send an alert if your age goes too high, threatening lost rewards.
If this seems implausible, consider that life insurer John Hancock already tracks a VitalityAge. With Obamacare incentivizing companies to engage policyholders in improving health, many are dangling rewards for fitness. BlueCross BlueShield covers 25 percent of InsideTracker's cost, and UnitedHealthcare offers a suite of such programs, including "missions" for policyholders to lower their Rally age. "People underestimate the amount of time they're sedentary," said Michael Bess, vice president of healthcare strategies. "So having this technology to drive positive reinforcement is just another way to encourage healthy behavior."
It's unclear if these programs will close health gaps, or simply attract customers already prioritizing fitness. And insurers could raise your premium if you don't measure up. Obamacare forbids discrimination based on pre-existing conditions, but will accelerated age qualify for this protection?
Liz McFall, a sociologist at the University of Edinburgh, thinks the answer depends on whether we view aging as controllable. "You can imagine payers clamoring to charge people for costs with a kind of personal responsibility to them," she said.
That outcome troubles Mark Rothstein, director of the Institute of Bioethics at the University of Louisville. "For those living with air pollution and unsafe water, in food deserts and where you can't safely exercise, then [insurers] take the results in terms of biological stressors, now you're adding insult to injury," he said.
Government could subsidize aging clocks and interventions for older people with fewer resources for controlling their health—and the greatest room for improving their epigenetic age. Rothstein supports that policy, but said, "I don't see it happening."
Bio age working for you
2030 again. A job posting seeks a "go-getter," so you attach a doctor's note to your resume proving you're ten years younger than your chronological age.
This prospect intrigued Cathy Ventrell-Monsees, senior advisor at the Equal Employment Opportunity Commission. "Any marker other than age is a step forward," she said. "Age simply doesn't determine any kind of cognitive or physical ability."
What if the assessment isn't voluntary? Armed with AI, future employers could surveil a candidate's biological age from their head-shot. Haut.ai is already marketing an uncannily accurate PhotoAgeClock. Its CEO, Anastasia Georgievskaya, noted this tech's promise in other contexts; it could help people literally see the connection between healthier lifestyles and looking young and attractive. "The images keep people quite engaged," she told me.
Updating laws could minimize drawbacks. Employers are already prohibited from using genetic information to discriminate (think 23andMe). The ban could be extended to epigenetics. "I would imagine biomarkers for aging go a similar path as genetic nondiscrimination," said McFall, the sociologist.
Will we use aging clocks to screen candidates for the highest office? Barzilai, the Albert Einstein College of Medicine researcher, believes Trump and Biden have similar biological ages. But one of Barzilai's factors, BMI, is warped by Trump miraculously getting taller. "Usually people get shorter with age," Barzilai said. "His weight has been increasing, but his BMI stays the same."
As for my bio age? InnerAge suggested I'm four years younger—and by boosting my iron levels, the program suggests, I could be younger still.
We need standards for these tests, and customers must understand their shortcomings. With such transparency, though, the benefits could be compelling. In March, Theresa Brown, a 44-year-old from Kansas, learned her InnerAge was 57.2. She followed InsideTracker's recommendations, including regular intermittent fasting. Retested five months later, her age had dropped to 34.1. "It's not that I guaranteed another 10 or 20 years to my life. It's that it encourages me. Whether I really am or not, I just feel younger. I'll take that."
Which leads back to Zhavoronkov's psychological clock. Perhaps lowering our InnerAges can be the self-fulfilling prophesy that helps Theresa and me age like the super-athletes who thrive longer than expected. McFall noted the power of simple, sufficiently credible goals for encouraging better health. Think 10,000 steps per day, she said.
Want to be 34 again? Just do it.
Yet, many people's budgets just don't allow gym memberships, nutritious groceries, or futuristic aging clocks. Bill Gates cautioned we overestimate progress in the next two years, while underestimating the next ten. Policies should ensure that age testing and interventions are distributed fairly.
"Within the next 5 to 10 years," said Gladyshev, "there will be drugs and lifestyle changes which could actually increase lifespan or healthspan for the entire population."
Matt Fuchs is the editor-in-chief of Leaps.org and Making Sense of Science. He is also a contributing reporter to the Washington Post and has written for the New York Times, Time Magazine, WIRED and the Washington Post Magazine, among other outlets. Follow him @fuchswriter.
In this week's Friday Five, attending sports events is linked to greater life satisfaction, AI can identify specific brain tumors in under 90 seconds, LSD - minus hallucinations - raises hopes for mental health, new research on the benefits of cold showers, and inspiring awe in your kids leads to behavior change.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on new scientific theories and progress to give you a therapeutic dose of inspiration headed into the weekend.
This episode includes an interview with Dr. Helen Keyes, Head of the School of Psychology and Sports Science at Anglia Ruskin University.
Listen on Apple | Listen on Spotify | Listen on Stitcher | Listen on Amazon | Listen on Google
- Attending sports events is linked to greater life satisfaction
- Identifying specific brain tumors in under 90 seconds with AI
- LSD - minus hallucinations - raises hopes for mental health
- New research on the benefits of cold showers
- Inspire awe in your kids and reap the benefits
Matt Fuchs is the editor-in-chief of Leaps.org and Making Sense of Science. He is also a contributing reporter to the Washington Post and has written for the New York Times, Time Magazine, WIRED and the Washington Post Magazine, among other outlets. Follow him @fuchswriter.
Residents of Fountain Hills, a small town near Phoenix, Arizona, fought against the night sky pollution to restore their Milky Way skies.
As a graduate student in observational astronomy at the University of Arizona during the 1970s, Diane Turnshek remembers the starry skies above the Kitt Peak National Observatory on the Tucson outskirts. Back then, she could observe faint objects like nebulae, galaxies, and star clusters on most nights.
When Turnshek moved to Pittsburgh in 1981, she found it almost impossible to see a clear night sky because the city’s countless lights created a bright dome of light called skyglow. Over the next two decades, Turnshek almost forgot what a dark sky looked like. She witnessed pristine dark skies in their full glory again during a visit to the Mars Desert Research Station in Utah in early 2000s.
“I was shocked at how beautiful the dark skies were in the West. That is when I realized that most parts of the world have lost access to starry skies because of light pollution,” says Turnshek, an astronomer and lecturer at Carnegie Mellon University. In 2015, she became a dark sky advocate.
Light pollution is defined as the excessive or wasteful use of artificial light.
Light-emitting diodes (LEDs) -- which became commercially available in 2002 and rapidly gained popularity in offices, schools, and hospitals when their price dropped six years later — inadvertently fueled the surge in light pollution. As traditional light sources like halogen, fluorescent, mercury, and sodium vapor lamps have been phased out or banned, LEDs became the main source of lighting globally in 2019. Switching to LEDs has been lauded as a win-win decision. Not only are they cheap but they also consume a fraction of electricity compared to their traditional counterparts.
But as cheap LED installations became omnipresent, they increased light pollution. “People have been installing LEDs thinking they are making a positive change for the environment. But LEDs are a lot brighter than traditional light sources,” explains Ashley Wilson, director of conservation at the International Dark-Sky Association (IDA). “Despite being energy-efficient, they are increasing our energy consumption. No one expected this kind of backlash from switching to LEDs.”
Light pollution impacts the circadian rhythms of all living beings — the natural internal process that regulates the sleep–wake cycle.
Currently, more than 80 percent of the world lives under light-polluted skies. In the U.S. and Europe, that figure is above 99 percent.
According to the IDA, $3 billion worth of electricity is lost to skyglow every year in the U.S. alone — thanks to unnecessary and poorly designed outdoor lighting installations. Worse, the resulting light pollution has insidious impacts on humans and wildlife — in more ways than one.
Disrupting the brain’s clock
Light pollution impacts the circadian rhythms of all living beings—the natural internal process that regulates the sleep–wake cycle. Humans and other mammals have neurons in their retina called intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells collect information about the visual world and directly influence the brain’s biological clock in the hypothalamus.
The ipRGCs are particularly sensitive to the blue light that LEDs emit at high levels, resulting in suppression of melatonin, a hormone that helps us sleep. A 2020 JAMA Psychiatry study detailed how teenagers who lived in areas with bright outdoor lighting at night went to bed late and slept less, which made them more prone to mood disorders and anxiety.
“Many people are skeptical when they are told something as ubiquitous as lights could have such profound impacts on public health,” says Gena Glickman, director of the Chronobiology, Light and Sleep Lab at Uniformed Services University. “But when the clock in our brains gets exposed to blue light at nighttime, it could result in a lot of negative consequences like impaired cognitive function and neuro-endocrine disturbances.”
In the last 12 years, several studies indicated that light pollution exposure is associated with obesity and diabetes in humans and animals alike. While researchers are still trying to understand the exact underlying mechanisms, they found that even one night of too much light exposure could negatively affect the metabolic system. Studies have linked light pollution to a higher risk of hormone-sensitive cancers like breast and prostate cancer. A 2017 study found that female nurses exposed to light pollution have a 14 percent higher risk of breast cancer. The World Health Organization (WHO) identified long-term night shiftwork as a probable cause of cancer.
“We ignore our biological need for a natural light and dark cycle. Our patterns of light exposure have consequently become different from what nature intended,” explains Glickman.
Circadian lighting systems, designed to match individuals’ circadian rhythms, might help. The Lighting Research Center at Rensselaer Polytechnic Institute developed LED light systems that mimic natural lighting fluxes, required for better sleep. In the morning the lights shine brightly as does the sun. After sunset, the system dims, once again mimicking nature, which boosts melatonin production. It can even be programmed to increase blue light indoors when clouds block sunlight’s path through windows. Studies have shown that such systems might help reduce sleep fragmentation and cognitive decline. People who spend most of their day indoors can benefit from such circadian mimics.
When Diane Turnshek moved to Pittsburgh, she found it almost impossible to see a clear night sky because the city’s countless lights created a bright dome of light called skyglow.
Diane Turnshek
Leading to better LEDs
Light pollution disrupts the travels of millions of migratory birds that begin their long-distance journeys after sunset but end up entrapped within the sky glow of cities, becoming disoriented. A 2017 study in Nature found that nocturnal pollinators like bees, moths, fireflies and bats visit 62 percent fewer plants in areas with artificial lights compared to dark areas.
“On an evolutionary timescale, LEDs have triggered huge changes in the Earth’s environment within a relative blink of an eye,” says Wilson, the director of IDA. “Plants and animals cannot adapt so fast. They have to fight to survive with their existing traits and abilities.”
But not all types of LEDs are inherently bad -- it all comes down to how much blue light they emit. During the day, the sun emits blue light waves. By sunset, it’s replaced by red and orange light waves that stimulate melatonin production. LED’s artificial blue light, when shining at night, disrupts that. For some unknown reason, there are more bluer color LEDs made and sold.
“Communities install blue color temperature LEDs rather than redder color temperature LEDs because more of the blue ones are made; they are the status quo on the market,” says Michelle Wooten, an assistant professor of astronomy at the University of Alabama at Birmingham.
Most artificial outdoor light produced is wasted as human eyes do not use them to navigate their surroundings.
While astronomers and the IDA have been educating LED manufacturers about these nuances, policymakers struggle to keep up with the growing industry. But there are things they can do—such as requiring LEDs to include dimmers. “Most LED installations can be dimmed down. We need to make the dimmable drivers a mandatory requirement while selling LED lighting,” says Nancy Clanton, a lighting engineer, designer, and dark sky advocate.
Some lighting companies have been developing more sophisticated LED lights that help support melatonin production. Lighting engineers at Crossroads LLC and Nichia Corporation have been working on creating LEDs that produce more light in the red range. “We live in a wonderful age of technology that has given us these new LED designs which cut out blue wavelengths entirely for dark-sky friendly lighting purposes,” says Wooten.
Dimming the lights to see better
The IDA and advocates like Turnshek propose that communities turn off unnecessary outdoor lights. According to the Department of Energy, 99 percent of artificial outdoor light produced is wasted as human eyes do not use them to navigate their surroundings.
In recent years, major cities like Chicago, Austin, and Philadelphia adopted the “Lights Out” initiative encouraging communities to turn off unnecessary lights during birds’ peak migration seasons for 10 days at a time. “This poses an important question: if people can live without some lights for 10 days, why can’t they keep them turned off all year round,” says Wilson.
Most communities globally believe that keeping bright outdoor lights on all night increases security and prevents crime. But in her studies of street lights’ brightness levels in different parts of the US — from Alaska to California to Washington — Clanton found that people felt safe and could see clearly even at low or dim lighting levels.
Clanton and colleagues installed LEDs in a Seattle suburb that provided only 25 percent of lighting levels compared to what they used previously. The residents reported far better visibility because the new LEDs did not produce glare. “Visual contrast matters a lot more than lighting levels,” Clanton says. Additionally, motion sensor LEDs for outdoor lighting can go a long way in reducing light pollution.
Flipping a switch to preserve starry nights
Clanton has helped draft laws to reduce light pollution in at least 17 U.S. states. However, poor awareness of light pollution led to inadequate enforcement of these laws. Also, getting thousands of counties and municipalities within any state to comply with these regulations is a Herculean task, Turnshek points out.
Fountain Hills, a small town near Phoenix, Arizona, has rid itself of light pollution since 2018, thanks to the community's efforts to preserve dark skies.
Until LEDs became mainstream, Fountain Hills enjoyed starry skies despite its proximity to Phoenix. A mountain surrounding the town blocks most of the skyglow from the city.
“Light pollution became an issue in Fountain Hills over the years because we were not taking new LED technologies into account. Our town’s lighting code was antiquated and out-of-date,” says Vicky Derksen, a resident who is also a part of the Fountain Hills Dark Sky Association founded in 2017. “To preserve dark skies, we had to work with the entire town to update the local lighting code and convince residents to follow responsible outdoor lighting practices.”
Derksen and her team first tackled light pollution in the town center which has a faux fountain in the middle of a lake. “The iconic centerpiece, from which Fountain Hills got its name, had the wrong types of lighting fixtures, which created a lot of glare,” adds Derksen. They then replaced several other municipal lighting fixtures with dark-sky-friendly LEDs.
The results were awe-inspiring. After a long time, residents could see the Milky Way with crystal clear clarity. Star-gazing activities made a strong comeback across the town. But keeping light pollution low requires constant work.
Derksen and other residents regularly measure artificial light levels in
Fountain Hills. Currently, the only major source of light pollution is from extremely bright, illuminated signs which local businesses had installed in different parts of the town. While Derksen says it is an uphill battle to educate local businesses about light pollution, Fountain Hills residents are determined to protect their dark skies.
“When a river gets polluted, it can take several years before clean-up efforts see any tangible results,” says Derksen. “But the effects are immediate when you work toward reducing light pollution. All it requires is flipping a switch.”