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Multivitamins may slow biological aging in older adults, study finds

The research focused on biological aging, which reflects wear and tear on the body at the cellular level.
Top view of various pills and tablets on the pink background
People in the study took either a multivitamin, cocoa extract, both or neither for two years.Yulia Reznikov / Getty Images
By Lindsey Leake
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For older adults, a daily multivitamin may slightly slow the aging process, new research suggests.

In a randomized study of 958 older adults, those who took a multivitamin daily for two years experienced slowed so-called biological aging by about four months. That is, during the 24 months, they aged only 20 months at a cellular level.

Whereas chronological age measures how much time has passed since birth, biological age reflects wear and tear on the body at a cellular level. The two don’t necessarily match up. For example, a person might be 50 years old chronologically yet have a biological age of 47 or 54 depending on factors such as genetics, lifestyle habits and medical history.

Howard Sesso, the associate director of preventive medicine at Brigham and Women’s Hospital and Harvard Medical School and the study’s senior author, cautioned that the results don’t mean a multivitamin adds four months to a person’s lifespan.

“What it means is that your trajectory of health moving forward should stand to benefit,” he said. “It’s hard to know what those four months truly translate to.”

What’s more, people who had shown signs of accelerated biological aging at the start of the trial saw a greater benefit from daily multivitamins. The findings were published Monday in the journal Nature Medicine.

The study was part of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a large Brigham and Women’s Hospital trial designed to show whether cocoa extract and/or multivitamins reduce the risk of developing cancer and heart disease. Researchers focused on a subset of healthy older adults: men 60 and older and women 65 and older, with an average chronological age of 70.

Participants were randomly assigned to one of four groups and took the following pills daily: cocoa extract and a multivitamin; a multivitamin; cocoa extract; or placebos.

The study was funded in part by Haleon, formerly Pfizer Consumer Healthcare, which provided the multivitamins, and Mars Inc., which provided the cocoa extract. Sesso and another author received funding from both companies, neither of which contributed to research design.

After two years, researchers used five so-called epigenetic clocks to estimate how much participants had biologically aged. These clocks, or biomarkers, analyze small changes in DNA over time.

Compared to the placebo-only group, people in the multivitamin group aged a bit more slowly, as measured by two of the five clocks.

One clock, dubbed PCGrimAge, showed slowed aging by about 1.4 months; the other, called PCPhenoAge, showed slowed aging by about 2.6 months. Sesso called these two biomarkers “second-generation clocks” that gauge mortality.

Participants in this group who had exhibited accelerated biological aging at the outset saw double the slowing of PCGrimAge, by about 2.8 months.

Cocoa extract didn’t have an effect on any of the five measures of biological aging.

“This is not to say that if you aren’t taking a multivitamin that you must start taking a multivitamin,” Sesso said. “The decision to take a multivitamin is still one that should be always taken in consideration with your health care provider.”

But if you’re already taking a multivitamin, he added, this new research suggests “there’s no reason to stop.”

What is biological aging?

Aging, whether biological or chronological, may seem concrete. In reality, “there is no gold standard measurement of aging,” Daniel Belsky, an associate professor of epidemiology at the Robert N. Butler Columbia Aging Center at Columbia University, co-wrote in a Nature Medicine commentary published alongside the study Monday. Belsky helped invent one of the epigenetic clocks used in the study: DunedinPACE, which is licensed to TruDiagnostic.

Though more black and white, chronological age has a spectrum. Especially as people live longer, 80 years might look different on a person who’s active and healthy compared with someone who’s bedridden and in poor health.

“I think of biological aging as the progressive loss of the integrity and resilience capacity of cells, tissues and organs with the passage of time,” Belsky said. “Happens to all of us. It’s the leading cause of almost all chronic disease and death.”

Danica Chen, a professor of metabolic biology, nutritional sciences and toxicology at the University of California, Berkeley, has been studying aging for more than 20 years. She said the biomarkers used in the study are “cutting-edge” but that additional research is needed before scientists can use them as a basis for recommending aging interventions, such as daily multivitamin use.

“We do not know yet whether [multivitamins] have an effect in improving tissue function or reducing disease risk,” said Chen, who wasn’t part of the study. The field of aging research “is at the stage that we are really just looking for even proof of concept,” she said.

Because the study period was only two years, Chen is interested to see whether older adults would see the same association with slowed biological aging after taking daily multivitamins long term.

The study has other limitations. Notably, most participants were white and healthy, so it’s unclear whether a more diverse population of older adults with chronic conditions might benefit.

The link between multivitamins and biological aging is modest, but Belsky said he’d be concerned if it weren’t.

“Nobody thinks taking a multivitamin is going to rejuvenate them,” he said.

Older adults may have unique supplement needs

Sesso, the study author, said that healthy aging doesn’t come down to one single thing; it’s a multifaceted process that requires being mindful of your holistic health.

“[The study] doesn’t take anything away from the importance of a good, balanced, diverse, colorful diet,” he said.

While the average healthy U.S. adult should ideally get the recommended vitamins and minerals from whole foods, some older adults face unique nutrition challenges that could possibly be helped with a multivitamin, said Joanne Slavin, a registered dietitian and professor in the department of food science and nutrition at the University of Minnesota.

For example, as some people age, they have a harder time opening cans and reading food labels, let alone preparing their own meals.

Food is getting more expensive, too, said Slavin, who wasn’t part of the study. Overall, prices in January were 2.9% higher than they were in January 2025, according to the consumer price index for food, published by the Agriculture Department’s Economic Research Service. Supermarket prices increased by 2.1% in that time frame.

But there are still a lot of questions around the nutritional needs of older adults.

“Most of our data that we’ve ever collected on how much of a vitamin does anybody need was collected in young people, and then we just scale up as best we can,” Slavin said. “There aren’t that many nutrients where we’d say, ‘Hey, older people need twice as much.’”

For instance, some older people may benefit from taking vitamin B12 supplements. It’s known that the body’s ability to absorb vitamin B12 decreases with age, and people 75 and older are at higher risk of deficiency.

Additionally, multivitamins contain so many vitamins and minerals that it’s difficult to decipher whether the observed changes in biological age may be associated with one or more ingredients in particular.

“Is it vitamin C? Is it folic acid?” Slavin said. “We don’t know.”

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Lindsey Leake

Lindsey Leake is an award-winning health journalist and contributor to NBC News. She holds an M.A. in science writing from Johns Hopkins University, an M.A. in journalism and digital storytelling from American University and a B.A. from Princeton University.