Is a Daily Multivitamin Enough to Slow Your Biological Aging Clock?

Key takeaways

• In adults around age 70, taking a daily multivitamin for two years was associated with slightly slower biological aging on five different DNA “epigenetic clocks.”

• On average, the difference equaled about four months less of biological aging over two years, with the strongest effect in people whose biological age was already higher than their actual age at baseline.

• The findings suggest multivitamins may become one accessible, relatively low‑risk tool for nudging aging biology, but they are not a dramatic anti‑aging solution, and more follow‑up work is needed.

How scientists measured “biological aging”

Chronological age is how many birthdays someone has had, while biological age tries to capture how quickly the body is wearing out at the cellular level, which can be faster or slower than the calendar. In this study, scientists used epigenetic clocks, tools that estimate biological aging by tracking small chemical tags (DNA methylation) that accumulate on DNA over time and are linked to gene regulation and health risk.

The team used data from the COSMOS trial, which enrolled 958 generally healthy older adults with an average age of about 70. Blood samples were collected at baseline, one year, and two years. Researchers analyzed DNA methylation patterns with five different epigenetic clocks, including some that are closely tied to risk of death and age‑related disease, to see how quickly each person’s biology appeared to be aging.

What the multivitamin actually did in the trial

Participants were randomly assigned to combinations of cocoa extract, multivitamin, or placebos, allowing the researchers to isolate the effect of the multivitamin. When they compared those taking a daily multivitamin with those taking a placebo, the multivitamin group showed slower increases in biological age across all five epigenetic clocks. Two of the clocks, which are especially predictive of mortality risk, showed statistically significant slowing.

Overall, the difference added up to an estimated four months less biological aging over two years—a subtle but measurable shift. The effect was most pronounced in people who started the study with “accelerated” biological age (their epigenetic age was higher than their chronological age), suggesting that those with faster aging biology might benefit the most. The trial does not prove that multivitamins lengthen life, but it indicates they may slightly influence molecular aging pathways.

What this could mean for brain and body health

The COSMOS team plans to follow participants further to see whether the observed slowing of biological aging relates to real‑world outcomes, such as thinking skills, physical function, and age‑related conditions. Earlier analyses from COSMOS have hinted that multivitamin use might support cognition in older adults and be linked to lower risks of some age‑related problems, and the new findings raise the possibility that modest shifts in biological age could help explain those patterns.

Researchers emphasize that a multivitamin is not a magic anti‑aging pill. It appears, at best, to provide a small nudge to aging biology, likely working alongside diet, movement, sleep, and other lifestyle factors. Still, because multivitamins are widely used, relatively inexpensive, and generally safe for most people, understanding even modest benefits could be important for supporting higher‑quality aging at the population level—especially for older adults whose biology is already aging faster than expected.

Caveats to consider

The study was funded and supported by a mix of public and private sources, including companies that supplied multivitamins and other study pills, and some investigators reported related research grants and honoraria—standard but important details when interpreting nutrition trials. The results also apply to a specific population: mostly healthy older adults, taking a particular type of multivitamin, over two years. They do not show what happens in younger people, over longer periods, or with different formulations.

Next steps include testing whether the slowing of biological aging holds up with longer follow‑up, whether it appears in other groups, and how it interacts with other interventions like diet quality and physical activity. For now, the work supports a nuanced takeaway: for older adults, a daily multivitamin may modestly slow certain molecular markers of aging, with the biggest potential benefit in people whose biology is already aging a bit too quickly. It is another small piece of evidence that simple, accessible interventions may have measurable—though not dramatic—effects on how we age at the cellular level.

References: 

1. Sidong Li, Rikuta Hamaya, Haidong Zhu, Brian H. Chen, Alexandre C. Pereira, Kerry L. Ivey, Pamela M. Rist, JoAnn E. Manson, Yanbin Dong, Howard D. Sesso. Effects of daily multivitamin–multimineral and cocoa extract supplementation on epigenetic aging clocks in the COSMOS randomized clinical trial. Nature Medicine, 2026; 32 (3): 1012 DOI: 10.1038/s41591-026-04239-3