I'm 36 and often get told I look younger, but a 'biological age' test said I'm almost 42 (2024)

Unfortunately, I've since learned, possessing the motivations of a college student (free food) does not mean preserving the DNA of one.

When my results came back weeks later, I discovered that despite being born a little over 36 years ago, swimming daily, never smoking, and being unable to enter a bar or even exit a Whole Foods without being carded, my "biological age" was nearing 42.

Here's what the experience was like and what I think consumers should know before going through it themselves.

Tally Health looks at DNA methylation

Taking the TallyAge test was like doing an at-home COVID-19 test, but instead of swabbing your nostrils, you swab your cheek. You then seal the sample, send it away, and hope for the best — or, as in my case, chug your first coffee of the day since you can't eat or drink in the 30 minutes before the test.

While there are many ways to estimate biological age, Tally Health looks at DNA methylation, or changes to genetic material that tend to occur with age. While the company, helmed by the Harvardlongevity researcher David Sinclair, isn't the first to offer this type of direct-to-consumer biological-age testing, it says its proprietary machine-learning model is superior to others, having been trained on "the largest and most diverse consumer DNA dataset" to date.

Tally Health also offers monthly memberships ranging from $130 to $200 so you can repeat the process and, ideally, stop or even reverse aging by making the company's recommended lifestyle changes (and taking their supplements), Sinclair told me.

But first, you have to know your baseline.

I suspected mine would be about 36. After all, past indicators have suggested I'm age-appropriate, even youthful.

A 2021 blood panel from my doctor raised no red flags, I placed in the top 5% of swimmers in the summer's New York City Triathlon, and makeup artists and broadcast hosts have commended my wrinkle-free skin. Visit me over the holidays after a few days with my parents, and you'll see I can act like a pouty preteen, too!

Sure, I have a few beers nearly nightly (unless it's January), sit for nine hours a day at my desk job, and consider myself a "healthy" eater because I order my Shake Shack wrapped in lettuce. But don't we all have virtues and sins?

Apparently not: When I clicked through to view my TallyAge via an online portal, I learned that my "biological age" was nearly six years older than my chronological age. Not only that, but I was also in the abysmal 4th percentile — in other words, 96% of my 36-year-old peers had organs sprightlier than mine.

My husband and best friends were shocked and even humored. I was angry.

Should I have frozen my eggs? Opted for ignorance and refused to take the test to begin with? Felt even more shame about habits I've struggled to change? Or, as a colleague asked, is it all just a bunch of "classic Silicon Valley BS?"

The lifestyle recommendations that were supposed to slow or reverse aging were predictable

When I called Tally Health's director of research and innovation, Adiv Johnson, distraught about missing my 40th birthday, he conceded that my placement in the 4th percentile was skewed.

While the pool of 8,000 cheek swabs the company used to help build its machine-learning model is diverse, he said, it also consists of the kind of people who signed up for the company's waiting list.

In other words, it's filled with affluent biohacking geeks eager to brag about their Benjamin Button status, not average Americans who have limited access to plant-based foods, lack quality healthcare, and work nights.

Still, the Tally Health team pushed me to view knowledge as power. Genetics determine less than 10% of longevity, they like to say, and the rest is up to lifestyle (if, of course, you have the privilege to change it).

"If you hadn't taken the test, you'd still be that age. Knowing that number is not making it true – it was always true," Sinclair said as he tried to comfort me over Zoom between sips of matcha and swallows of supplements. "Now, at least, you can take action."

But some of the actions the Tally Health platform prescribed based on a "lifestyle survey" I filled out after receiving my results are easier said than done, and many of the others didn't require a sleek test to spell out.

For example, because I rated my social satisfaction and feelings of purpose as mediocre, the platform told me I should — wait for it — "increase life purpose" and improve my social life. Other recommendations were more practical but not surprising: Eat less red meat and more fish, sit less and sleep better, drink less and meditate more.

I did appreciate how the platform tiered it recommendations: For example, I could make a few smaller, more-manageable shifts to my diet, sleep, and movement or one bigger change to my alcohol intake for the same health-span-lengthening results. But I wondered why a test that's apparently so specific to my personal DNA dished out advice so, well, generic.

Matt Kaeberlein, the director of the University of Washington's Healthy Aging and Longevity Research Institute, told me that because, like other direct-to-consumer kits, Tally Health tests weren't regulated by the Food and Drug Administration, they couldn't dole out medical advice.

"That's part of why everybody who's done these tests feels a little bit let down in the information you get back, which is, 'Eat more vegetables, exercise more, get better sleep,'" he said.

Some people may find learning their biological age motivating. I found it anxiety-provoking.

Kaeberlein also assured me that while DNA methylation was a highly regarded way to gauge how well or poorly you're aging, it's not the only way — and using only it to test for biological age was flawed.

"These methylation tests are really measuring one small piece of the type of molecular changes that go along with aging, but you could just as easily build a biological-age test off of functional measures like grip strength or how fast you can run or how much weight you can bench-press," he said.

Kaeberlein also took issue with the rush to commercialize complicated — and, in many ways, nascent — longevity research. Sinclair's work, for one, draws on rat studies that have yet to be replicated in humans.

"I'm a little bit concerned it's going to be harmful to the reputation of the field in the long run because when you overpromise and underdeliver, people tend to remember that," Kaeberlein said of biological-aging tests in general.

The kits also aren't cheap, and while some people may find they motivate positive behavioral change, he said, others adopt the "screw it" philosophy and develop anxiety. Perhaps it's a sign of maturity that, for me, the free coffee wasn't worth it.