A new study suggests that a simple daily habit may quietly support healthier aging.
For many people, taking a multivitamin is a small act of self-care, often viewed as a way to fill nutritional gaps in the modern diet. Now, emerging research suggests these supplements may offer an additional benefit: they may modestly influence the biological processes that shape how quickly our bodies age.
A large randomized clinical trial published in Nature Medicine found that adults who took a daily multivitamin-multimineral supplement for two years showed measurably slower biological aging compared to those who received a placebo.
The effect was modest, but notable. In a field where many anti-aging interventions involve restrictive diets or experimental treatments, the idea that an over-the-counter supplement could influence biological aging has drawn increasing scientific interest.
Understanding Biological Aging
While chronological age simply reflects the number of years we’ve lived, biological age measures how our bodies are actually functioning at the cellular level.
Scientists now use tools known as epigenetic clocks to estimate biological age. These clocks analyze chemical markers that accumulate on DNA over time, providing insight into how quickly the body is aging internally.
Two people who are both 70 years old, for example, may show very different biological profiles. One person’s cells may resemble those of someone several years younger, while another may display signs of accelerated aging. These differences are linked to real health outcomes, including risks for cardiovascular disease, cancer, and cognitive decline.
In the new study, researchers focused on two well-established epigenetic clocks designed to predict long-term health risks. Participants who took a daily multivitamin showed a slower increase in biological age markers over the two-year study period.
The difference translated to roughly 2.5 to 5 months of reduced biological aging compared with participants who took a placebo.
Who Benefited the Most?
One of the study’s most interesting findings was that the benefit was strongest among individuals whose biological age was already advancing faster than expected.
Participants who entered the study with accelerated biological aging tended to have lower levels of key nutrients, including folate and lutein. Over time, multivitamin use appeared to raise those nutrient levels.
Researchers believe this may help explain the results. When subtle nutritional deficiencies place stress on the body’s cellular systems, correcting those gaps may help support healthier biological function.
Because the participants in the study were generally healthy older adults, researchers note that the benefits may be greater among populations with less optimal diets or higher rates of nutrient deficiencies.
Inside the COSMOS Trial
The research was conducted as part of the COSMOS trial, a large randomized study involving more than 21,000 adults across the United States.
For this analysis, scientists evaluated blood samples from 958 participants aged 60 and older, measuring DNA markers at the beginning of the study and again at one- and two-year intervals.
Participants were randomly assigned to receive either a daily multivitamin supplement or a placebo. More than 90 percent of those taking the supplement continued the regimen throughout the two-year period, providing strong consistency in the data.
The study also evaluated cocoa extract supplements, which contain plant compounds called flavanols that have shown cardiovascular benefits in earlier research. However, the cocoa extract showed no measurable effect on the biological aging markers examined in this study.
A Small Shift with Meaningful Potential
While researchers caution that more long-term studies are needed, the findings add to a growing body of research suggesting that multivitamins may support healthy aging.
Previous results from the same COSMOS trial have linked daily multivitamin use with slower cognitive decline and modest reductions in cancer risk among older adults.
Whether the observed changes in biological aging ultimately translate into longer lifespans or improved long-term health remains an open question. But the results suggest that a daily multivitamin may be doing more than simply filling nutritional gaps.
It may also help support the body’s natural resilience as we age.
Research Source
This article is based on findings from the study “Effects of daily multivitamin-multimineral and cocoa extract supplementation on epigenetic aging clocks in the COSMOS randomized clinical trial,” published in Nature Medicine on March 9, 2026.
The research was led by Howard D. Sesso of Mass General Brigham and Brigham and Women’s Hospital and conducted as part of the COSMOS clinical trial.
Read the full study:
https://doi.org/10.1038/s41591-026-04239-3
