What’s enticing about this is that if you then make efforts to reduce your biological age by changing your habits, the test might be able to give you a reality check, and tell you whether you are succeeding. Just be aware that tests from different companies will measure different sets of patterns, and the results may not match.
Epigenetic tests don’t need to be approved by the Food and Drug Administration, and company disclaimers state that they don’t screen for or assess disease risk. But already, some life insurance companies have begun using the tests, along with the usual physical exams and family history, to predict your lifespan.
Generally, though, these tests aren’t fortune tellers. You won’t learn exactly how long you have left to live. For one thing, random events—a serious infection, a car accident—play a huge role in lifespan. For another, the test was designed to apply to a population, rather than an individual. It’s one thing to say that a group of people who share a similar pattern of methylation changes will, on balance, live longer. It’s quite another to accurately forecast one specific individual’s lifespan. “It’s not the case we could nail down the date of death of an individual within plus or minus one year,” Horvath says.
Nonetheless, Horvath took his own test when he was 51, to see what it would tell him about how fast he is aging. His biological age was 48.9. His identical twin took the test, and interestingly, his result was exactly the same: 48.9.
That doesn’t exactly mean Horvath will live precisely two years longer than expected. It’s a kind of shorthand, a simple way to convey whether you’re aging more quickly or slowly than the average person.
Morgan Levine, a gerontologist and biostatistician at Yale University, created DNAm PhenoAge when she previously worked in Horvath’s lab. Her test was designed to reflect the risk of major diseases as well as overall lifespan. Beginning in January, her newest epigenetic clock will be sold as a commercial test beginning in January for $500 from the company Elysium Health, where she is head of bioinformatics. It measures patterns at 150,000 DNA methylation sites, which she says enhances its predictive value.
Levine views the test as a tool for personalized prevention, enabling people to see if their healthy lifestyle changes cause their epigenetic age to decline, making them biologically younger. “This is much more reflective of lifestyle and behavior” than a genetic test, says Levine. “People have much more power over this number.”
Commercial epigenetic testing is in its infancy, so consumers should be wary if companies make claims about a specific disease risk or offer to precisely predict lifespan—or use the results to market other products, says Robert Green, a medical geneticist at Brigham and Women’s Hospital in Boston who has studied direct-to-consumer genetic testing. “They have to understand that there’s a difference between something that is provided by a consumer-facing company and something that is recommended with the full force of medical science behind it,” says Green, cofounder of Genome Medical, which provides an online consultation service for people who undergo genetic testing.
If you learn from an epigenetic test that you should improve your diet, lose weight, stop smoking, exercise more, and get more sleep—well, that’s advice you knew before shelling out a few hundred bucks. Still, sometimes a test result—genetic or epigenetic—may be what motivates you to actually change your habits, Green says.
At 34, Levine is conducting her own personal experiment. She took her test last year; it showed her biological age to be 2.5 years younger than her chronological age. Previously a vegetarian, runner, and equestrian, she has now gone vegan and switched her workouts to high-intensity training, which has been linked to anti-aging changes in muscle. She plans to re-test monthly to see if her new regimen slows her biological aging.