The notification lit up Michelle’s phone at 5:25 a.m. on the West Coast: a text from her older sister, Deb, who had an idea.
Deb had heard on a longevity podcast about a new technology that claimed to measure how quickly a person was aging. For $399, each sister could submit a blood sample and learn how her habits and experiences had affected the ways her genes behaved. The test, called TruAge, could supposedly tell them the functional ages of their brains, hearts, lungs and bodies overall.
“I think it would be super interesting to look at test results between siblings,” Deb, 56, had written. “You interested?”
“Yes, I would love to,” Michelle, 54, replied. “I fear the results, though.”
When it came to their genetics, the sisters seemed remarkably alike. (They asked to be identified using only their first names to discuss sensitive medical information.) They had the same deep-set, ice-blue eyes, the same prominent cheekbones, the same blond hair that swirled from a cowlick on the back-right corner of their heads. They both had astigmatism and night blindness; neither could roll her tongue or sing on pitch. And they had the same unusual variant of a gene called ABCC11, which meant their armpit sweat never had any odor.
Deb and Michelle, raised together in Detroit, knew they shared roughly half their DNA, but sometimes they had a hard time believing it. Deb, who now lived in Virginia, had always been hyper-disciplined, pragmatic and outgoing. A former Air Force nurse, she had traveled the world and raised three children, and seemed to exercise nonstop. Michelle was sensitive and bookish — so introverted that she didn’t even own a calendar. She had settled into the central valley of California after high school and never married. She lived a quiet, contented life with one companion: her Herder-Pit mix, Merlin.
There was another key difference: Deb had always been healthy, aside from mild joint pain and high cholesterol that medication kept under control. But Michelle had been obese in her teens and 20s and later struggled with autoimmune issues that no doctor had been able to fully explain. Every day was some constellation of extreme fatigue, nerve pain and tachycardia from low blood pressure. When Deb’s text arrived, Michelle was dealing with swollen lymph nodes, bumps all over her hands and a rash that stretched into her ear canals and nostrils.
Deb told her sister that maybe the test could help her better understand the causes and effects of her ailments. After years of feeling dismissed by doctors, maybe Michelle would feel validated if her biological age reflected her suffering.
Deep down, Michelle had a feeling that Debbie — she would always be Debbie to Michelle — just wanted to outperform Michelle. Still, Michelle wasn’t going to miss the first opportunity in years to do something with her sister. As adults, the two had grown distant, and then, after a bitter fight, stopped talking at all for almost two decades. They had reconnected only a few years ago, and even now, only through texts.
“Do you have a website so I can look at it?” Michelle asked.
The test’s marketing materials promise “the most complete picture of how your body is aging.” It analyzes almost one million chemical tags on DNA that make up a person’s epigenetics, the layer of biological instructions that controls how someone’s genes are expressed. By comparing a person’s unique pattern against large databases of other people’s results and health outcomes, its models try to assign an “age” that reflects the person’s predicted level of health.
Many aging test algorithms have proved effective for comparing large groups of people in scientific studies. But critics — and even some scientists who have developed the algorithms — say they are not meant to evaluate individuals, and that with so much statistical noise and potential for error, these tests are far too premature for commercial use. Most doctors believe a comprehensive blood panel is, for now, far more actionable.
And yet, biological aging tests like TruAge have in recent years exploded into an industry worth nearly $3 billion, a mark of a world that cannot resist the allures of personal wellness data. As with a personality test — or even a horoscope — proven accuracy is hardly a requirement. People crave new ways to define themselves.
When Deb’s test package arrived by mail, she arranged the contents neatly across her kitchen table. She pricked her middle finger with the lancet and squeezed dozens of drops of blood onto a paper card. Before she had even applied a bandage, she was using her other hand to text advice to Michelle, who had pricked her own finger but couldn’t seem to generate enough blood to fill the card.
“Wash hands in warm water,” Deb wrote her. “Do a few jumping jacks. Make fists. Really squeeze.”
“I bet this is a low blood pressure issue,” Michelle texted. “I’m trying.”
“Keep trying,” Deb replied.
Michelle pricked a second finger and eventually filled her card. Then both sisters packaged their samples and dropped them at their post offices, the envelopes addressed to the same lab in Kentucky.
Deb sent another text: “And now we wait.”
Deb was ahead of schedule, even for Deb. She stood at the kitchen counter of her glass-paned house, chopping vegetables for her homemade microbiome mix. She would combine them with plant-based protein powders and fiber mixes for her meal-replacement smoothie at lunch.
Deb and her husband, Steve, had become empty nesters in recent years, and Deb was often alone in a four-bedroom house so quiet she could hear the insects in the woods out back. Steve, a military contractor, typically worked 18-hour days, so Deb had taken on shifts as a nurse at a local aesthetic medicine practice, but she still had a lot of time to fill.
Years ago, to stay healthy, she had started walking 15,000 steps per day, strength-training at the gym and keeping a sugar-free diet. But as Deb became more interested in longevity, she added more habits, until she was using red light therapy daily, taking pills to increase antioxidant production and mitochondrial function, and experimenting with acupuncture and herbal patches.
She didn’t have a primary care doctor, and she didn’t think she needed one. All of her biohacks were already based on personalized insights. She had done a test to check for calcium buildup in her heart’s arteries, multiple scans to measure the strength of her bones, and a mail-order analysis called the 3X4 Blueprint that supposedly revealed which genes made her more susceptible to dementia, chronic inflammation and connective tissue decay.
Deb fed all her health information into ChatGPT, which then guided her to the best vagus nerve stimulators and chemical peels and fiber gummies — and also more assessments. It was ChatGPT that had convinced Deb to order the TruAge test in the first place.
“You’ve spent the past year optimizing almost every major longevity lever,” the chatbot told her after she asked it about the test’s value. TruAge, it said, “can help answer whether the protocol you’ve assembled is changing your biological trajectory.”
After she finished preparing her microbiome mix, Deb stopped by a refrigerator in her home office where she kept her vials of peptides. She injected one for tissue repair, another to reduce inflammation, another to help detox her skin and liver.
Then she reached for a small container of old photographs. Inside were snapshots of the life she and Michelle had once shared: a photo labeled “APRIL ’78” of the girls at ages 6 and 8, standing side by side in their grandparents’ house. Another marked “FEB. ’79,” of the two in matching white jackets, with identical bobs and wide, toothy grins that crinkled the corners of their eyes.
They were convincing portraits of a happy childhood, and Deb, a master compartmentalizer, preferred not to think about the chaos they elided: her mother’s erratic outbursts; their parents’ volatile fights; the constant extramarital affairs, which the girls often knew about. Sometimes the adults would disappear for long stretches of time, leaving the sisters to forge notes to their teachers and fend for themselves.
Increasingly, their paths had differed: Deb grew long and thin and gregarious, while Michelle withdrew behind more and more weight. Deb became a cheerleader, earned straight A’s and spent more time with her boyfriend’s family than her own. In the final photo of the sisters, taken on a Florida pier in “JULY ’84,” Deb’s arms were draped over a friend’s shoulders while Michelle stood off to the side, shorts bunched between her thighs, smiling alone.
“I’ve had a good life,” Deb said, tucking away the photos. “And Michelle really struggled.”
Deb couldn’t remember the details of their estrangement, but Michelle had long been a painful reminder that Deb, as the elder sister, needed to be the adult in the house, even when she was still a child. She was pretty sure the breaking point had taken place in their 30s, when Michelle got wrapped up in a horrible relationship with a guy Deb couldn’t stand. Deb had always been able to cut anyone out of her life without a second thought, so she did.
Then, after almost 20 years, Michelle reached out in a text message, apologizing for her role in the conflict. They began messaging again, but when Michelle called, Deb sent it to voice mail and texted her instead. Something about the thought of actually speaking to Michelle set off panic in Deb’s chest, even now.
Deb had always expected that her biological age would be younger than Michelle’s. But in the silence of her empty house, she began to consider other possibilities. What if Deb’s heavy partying in her 20s had super-aged her liver? What if her natural cholesterol levels, which were beyond her control, were causing vascular damage? What if her younger sister “had been able to trick her body in some way,” Deb wondered, and prove that all of Deb’s protocols were for nothing?
“I’m not going to crawl into bed and die,” she reassured herself. No, she would simply need to do more research.
In a sun-baked agricultural town across the country, less than two weeks before the TruAge results would arrive, Michelle arose before dawn with no agenda at all.
She curled up in an armchair in her sweatpants to watch the sunrise, then drew the blinds, blasting the air-conditioner and multiple industrial-grade fans to ward off her symptoms of heat intolerance.
Michelle watched a women’s basketball game and nuzzled her dog, Merlin, and decided not to worry about all the chores piling up during this latest bout of fatigue: the cobwebs in the ceiling corners, the listing side-yard fence, the suitcase she hadn’t found the energy to unpack. She had taken that trip a month ago.
Michelle wandered over to a shelf overflowing with tubs of salves and took her medicine. Then she donned her dark sunglasses, which helped her deal with extreme photophobia outdoors. “Come on, Bubba,” she said to Merlin, who leaped toward the door. Michelle wanted to go on one of their long drives — the road seemed to help her think.
Michelle had not dwelled much on the test since she’d taken it. A part of her thought the whole thing might be pseudoscience. Michelle had at least seven specialists in a regular rotation, including an allergist, a neurologist, a podiatrist and a dermatologist — almost two centuries’ worth of collective clinical experience that still left her “playing connect-the-dots,” she said. She was dubious that a few drops of blood were going to finally reveal the full picture.
But Michelle had a mental health counseling degree and read more than 200 books a year, many of them about psychology. She had been thinking lately about the ways toxic stress might leave lasting scars on human DNA. Now she couldn’t help but wonder if the kit’s algorithms might be programmed to measure something deeper.
As a child, Michelle had internalized the turmoil in their home — a factor she believed contributed to her rashes and sinus infections and overeating. She remembered the way their mother would throw items like screwdrivers and books at them; the tree Michelle climbed to hide herself on the roof of their detached garage; the maggots in the food when she and Deb were routinely left alone for weeks.
With every year, Michelle felt increasingly unstable, but somehow Debbie just became more capable, focused solely on the tasks at hand. When Michelle was 8 and came down with scarlet fever, Debbie put her on her bicycle’s handlebars and pedaled her to the corner store for medicine. When Michelle was 10 and broke her arm, Debbie taped two rulers together to hold it straight.
Michelle could tell that Debbie’s recollection of all those shared years was spotty — and that Debbie preferred it that way. It seemed as if Debbie mostly just remembered that she had managed the house, gone off to college and kept on thriving, in part because of her ability to simply choose what to forget.
But the trauma of their childhood had colored the first half of Michelle’s life. She ate addictively until she was 342 pounds and needed weight-loss surgery. She gravitated toward abusive relationships, staying in one for 14 years. And then, one night in 2007, Michelle was attacked by three men in a Walmart parking lot and sustained a traumatic brain injury, broken facial bones and a blown-out eardrum that left her partly deaf.
That was when Michelle decided to invest in “holistic healing,” she said. She earned her counseling degree, took a job with a disability advocacy group and started volunteering at a homeless shelter. She also eventually reached out to Debbie. Michelle finally found her stability — not in her physical being, but her emotional one.
Sometimes she suggested that Debbie consider therapy. “Seeing our younger selves is not reliving the childhood,” Michelle explained. But Debbie had no interest. “The trail is my therapy,” she would say. Now Michelle wondered: Could all that compartmentalization have done something to Debbie’s cells?
Driving along the California Delta, with Merlin’s paws perched on the center console beside her, Michelle felt at peace with most of her predictions for the test’s results. Her immune cell composition would not score well, and her brain had most likely undergone accelerated aging from the attack.
But Michelle couldn’t shake her worry that maybe it was Debbie who had not been able to outrun their childhood. There were 11 days until the reveal, and the test was starting to feel like a kind of ledger of their lives, both together and apart. She desperately hoped her own biological age would be older than Debbie’s — to protect her sister and maybe their newly mended relationship.
But if Michelle fared younger, then what? “Should I lie?” she asked herself as she pulled back into her driveway.
Perhaps this would be her way of finally taking care of the sister who had tried to take care of her. Maybe a “little white lie” — just for Debbie — would be worth it.
Deb had been refreshing her TruAge online portal every couple of days, but Michelle’s results landed first.
They ran to 73 pages of data, including stress markers, nutrient levels and toxin exposures. Plastered across the top were three key metrics: an overall score that encompassed a lifetime of chemical tags; another that measured the “pace” at which the body was supposedly aging; and, finally, a score that focused on the body’s organs, looking at markers associated with 11 different systems. Michelle leaned back in her recliner and began to scroll.
There was no sugarcoating the first score: Though Michelle was just 54, the test declared her overall “biological age” to be 62.
She threw back her head and laughed. “They’re saying I’m a senior citizen at this point,” she said. “If I was unstable mentally, this would not be a good thing!”
But the other two delivered what seemed like good news. Her aging “pace” score said that for every year that passed, she would age only 0.98 years — an indicator of a healthy lifestyle in recent months.
And her organ ages surprised her even more: All 11 organ systems together averaged to a relatively youthful 53.4. Her lungs were 53.6; her brain was 53.8, despite her traumatic brain injury. And even with all of Michelle’s autoimmune issues, her inflammation system was, inexplicably, 52.4. The report had even marked some of Michelle’s organ systems with mint green smiley-face icons to indicate slow aging.
“This is getting more interesting,” she said. But she had yet to hear from Deb.
“Your TruAge results are probably in your email,” she texted.
“Nope,” Deb replied. She had even checked her Spam folder.
Michelle had not anticipated this scenario, but she didn’t feel she could withhold her results. Soon, Deb was scouring through Michelle’s packets, taking in all the diagrams.
“I think considering all you’ve been through, the results are pretty darn great,” Deb texted. “It will be interesting what mine says.”
She waited another day — then another, and another. At the end of Week 4, she received an alert from the company that the laboratory needed to reprocess her sample because the results “did not meet one of the laboratory’s quality standards.”
“Now I’m anxious,” she texted Michelle.
On the last day of the sixth week, Deb had just returned from a morning walk when her inbox pinged: “Your full results are ready now.” She clicked into the portal and pressed “View My Results.”
Deb leaned closer to the screen and swallowed. The 56-year-old’s overall score was 58.3 — higher than she would like, but still younger than her sister’s, she reminded herself. And she was aging at a pace of 0.90 each year — good news.
But then she scrolled down to the organ results. She covered her mouth. “What the hell?”
Every result seemed astronomical — they averaged out to 63.5, more than a decade older than Michelle’s. Many were even scarier: Her lungs were 64.7. Her heart was 64.3. Her liver was 63.9. Her immune system was 66.7, compared with her immune-deficient sister’s 57.8.
Deb had longed to see those mint green smiley faces throughout her report. Instead, TruAge had marked Deb’s overall score and all 11 organ systems with magenta sad faces: “Aging Faster.”
Deb closed her laptop and got ready for work, but she spent the day in a private vortex of grief. Had she exercised too hard the day before she took the test, or not slept enough? Or maybe the results were accurate, and no amount of effort could override her unlucky DNA. Either way, she didn’t know what to do next.
That was the problem many health experts had with biological age test results: There was no consensus on how to act on them. A doctor would have told Deb not to worry much about her scores, to focus instead on age-old advice: Stay active, eat healthfully and enjoy her years. But the emotional undertow of the wellness era seemed to suggest that was no longer enough.
Michelle was concerned for her sister. She pinged Deb with encouraging text messages about all the reasons her results were probably skewed. Perhaps Deb should consider finding a primary care doctor, Michelle suggested, who could help put everything in perspective.
But Deb did not want to wait. She asked ChatGPT for advice instead, and it helped her choose a host of new biomarker tests she could order from a website that didn’t require a doctor’s visit and reported results using an A.I. assistant named Barry.
Deb texted Michelle a screenshot from the site, where she had spotted a host of new blood panels that the company planned to roll out. There was one focused on “genetic health insights”; another to detect brain changes related to Alzheimer’s disease; a third to measure PFAS, or “forever chemicals,” that might have accumulated in the body over time.
“Look what’s coming,” Deb wrote. “Fascinating.”
Michelle was happy for any excuse to correspond with Debbie. There still weren’t any phone calls — too emotionally triggering, Michelle guessed — and she assumed that when they ran out of wellness metrics to talk about, her sister’s texts would dry up. But for now, Michelle and Debbie wrote back and forth about lab orders they would place together and chatted about all the ways their genes must be expressing themselves: the same antibody deficiencies, the same pattern of graying hair. Together, they marveled at how much two sisters could share.
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