Multivitamins may slow biological aging in older adults, study finds

For older adults, a daily multivitamin may slightly slow the aging process, new research suggests.

In a randomized study of 958 elderly people, those who took a daily multivitamin for two years saw a slowdown in so-called biological aging by about four months. In other words, over the course of 24 months, they only aged 20 months at the cellular level.

While chronological age measures the time since birth, biological age reflects wear and tear on the body at the cellular level. The two do not necessarily match. For example, a person may be 50 years old chronologically but have a biological age of 47 or 54 depending on factors such as genetics, lifestyle habits, and medical history.

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

“That means your health trajectory should benefit,” he said. “It’s hard to know what those four months actually amount to.”

Additionally, people who showed signs of accelerated biological aging at the start of the trial saw greater benefit from daily multivitamins. The results were published Monday in the journal Nature Medicine.

The study was part of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a large trial at Brigham and Women’s Hospital designed to show whether cocoa extract and/or multivitamins reduce the risk of developing cancer and heart disease. The 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 multivitamin; a multivitamin; cocoa extract; or placebos.

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

After two years, the researchers used five so-called epigenetic clocks to estimate the biological aging of the participants. These clocks, or biomarkers, analyze small changes in DNA over time.

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

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

Participants in this group who had exhibited accelerated biological aging at the start saw the slowdown in PCGrimAge double, by approximately 2.8 months.

Cocoa extract had no effect on any of the five measures of biological aging.

“This doesn’t mean that if you’re not taking a multivitamin, you should start taking them,” Sesso said. “The decision to take a multivitamin should always be considered 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, can seem concrete. In reality, “there is no gold standard measure of aging,” co-wrote Daniel Belsky, associate professor of epidemiology at Columbia University’s Robert N. Butler Columbia Aging Center, in a commentary in Nature Medicine published Monday alongside the study. Belsky helped invent one of the epigenetic clocks used in the study: DunedinPACE, which is licensed by TruDiagnostic.

Although more black and white, chronological age has a spectrum. Especially as people live longer, 80 years may look different for an active, healthy person compared to someone who is bedridden and in poor health.

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

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

“We don’t yet know if [multivitamins] have an effect on improving tissue function or reducing disease risk,” said Chen, who was not part of the study. The field of aging research “is at the stage where we’re just looking for proof of concept,” she said.

Since the study period was only two years, Chen wants to see if 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 illnesses might benefit.

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

“No one thinks that taking a multivitamin is going to make them look younger,” he said.

Older adults may have unique supplement needs

Sesso, the study’s author, said healthy aging isn’t about just one thing; it’s a multi-faceted process that requires paying attention to your holistic health.

“[The study] does not take away from the importance of a good, balanced, diverse and colorful diet,” he said.

While the average healthy American adult should ideally get recommended vitamins and minerals from whole foods, some older adults face unique nutritional challenges that could potentially be addressed with a multivitamin, said Joanne Slavin, a registered dietitian and professor in the University of Minnesota’s department of food science and nutrition.

For example, as some people get older, they have more difficulty opening cans and reading food labels, let alone preparing their own meals.

Food is also getting more expensive, said Slavin, who was not involved in the study. Overall, prices in January were 2.9% higher than in January 2025, according to the Food Consumer Price Index, published by the Economic Research Service of the Ministry of Agriculture. Supermarket prices increased by 2.1% during this period.

But many questions remain about the nutritional needs of older people.

“Most of the data we’ve collected on how much vitamin someone needs has been collected from young people, and then we increase it as best we can,” Slavin said. “There aren’t many nutrients that we would say, ‘Hey, older people need twice as much.'”

For example, some older adults might benefit from vitamin B12 supplements. It is known that the body’s ability to absorb vitamin B12 decreases with age and that people aged 75 and over are at higher risk of deficiency.

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

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