What the New Study Found
A daily multivitamin could do more than fill nutritional gaps — it may actually slow how fast your body ages at the cellular level. A landmark new study published in Nature Medicine found that older adults who took a daily multivitamin-multimineral supplement reduced their biological aging by up to four months over a two-year period.
The research is part of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a large-scale randomized clinical trial that included 958 adults aged 60 and older. Participants received either a daily multivitamin — specifically Centrum Silver — or a placebo. Researchers then tracked changes using five established measures of biological aging known as epigenetic clocks.
This is one of the few randomized trials ever to test whether a common supplement can directly slow biological aging. The results add compelling new evidence to a long-running scientific debate.
Biological Age vs. Chronological Age
Most people count age one way: by the number of years they have lived. However, scientists use a different measure called biological age, which reflects how much wear and tear the body has experienced at a cellular level.
Biological age and chronological age do not always match. A 50-year-old, for instance, may have a biological age of 47 or 54 depending on factors like genetics, lifestyle, and medical history. Moreover, biological age is a stronger predictor of long-term health outcomes than the number of candles on a birthday cake.
This distinction matters because it shifts the focus from simply living longer to living better.
How Multivitamins Affect Epigenetic Clocks
What Are Epigenetic Clocks?
Epigenetic clocks are molecular tools that measure biological aging by tracking chemical changes on DNA, specifically a process called DNA methylation. These changes occur in specific parts of the genome and can estimate a person’s true biological age with remarkable accuracy.
What the COSMOS Trial Measured
The study tracked five DNA methylation markers. Participants who took daily multivitamins showed modest but statistically significant reductions in two key aging markers — PCGrimAge and DunedinPACE — both of which are strongly linked to longevity and long-term health outcomes.
Importantly, the cocoa extract supplement tested in the same trial showed no similar benefit, suggesting the effect was specific to the multivitamin-multimineral combination.
Who Benefits the Most
Not everyone experienced the same level of benefit. Participants who entered the trial with a biological age already older than their chronological age — meaning their bodies showed signs of accelerated aging — gained the greatest advantage from daily multivitamin use.
This finding suggests that people who are most nutritionally deficient or biologically stressed may respond most strongly to supplementation. Furthermore, it points to the value of early intervention before aging accelerates.
What Experts Say
Optimism Tempered by Caution
Senior study author Howard Sesso, Associate Director of Preventive Medicine at Brigham and Women’s Hospital and Harvard Medical School, emphasized that the results do not mean a multivitamin literally adds four months to a person’s lifespan.
“What it means is that your trajectory of health moving forward should stand to benefit,” Sesso said. “It’s hard to know what those four months truly translate to.”
Independent Experts Weigh In
José Ordovás, a professor of nutrition and genetics at Tufts University, called the findings interesting but incomplete. “The multivitamin produced small favorable changes in two epigenetic aging markers, but not across all the clocks that were measured,” he noted. “That makes the finding interesting, but it is still far from showing that multivitamins broadly slow aging or improve longevity.”
Zachary Clayton, an assistant professor of medicine at the University of Colorado Anschutz, added that while the study was well-designed, the clinical significance of the changes remains uncertain. He also pointed out that individual diet and physical activity during the trial were not fully accounted for.
Should You Take a Daily Multivitamin?
Multivitamins are the most commonly used dietary supplement in the United States. Yet their health benefits have long been debated, and none are approved by the U.S. Food and Drug Administration for treating or preventing disease.
Still, nutritional deficiencies are genuinely common among older adults. For example, the body’s ability to absorb vitamin B12 naturally declines with age, and adults 75 and older face a particularly high risk of deficiency. Additionally, most nutritional research has historically focused on younger populations, leaving gaps in our understanding of what older adults specifically need.
Therefore, while a multivitamin is not a substitute for a balanced diet, it may serve as a practical, low-cost safety net for older adults — especially those with dietary gaps or signs of accelerated biological aging.
Notably, the study was partially funded by Haleon (formerly Pfizer Consumer Healthcare) and Mars Inc., which supplied the supplements. Two authors received funding from both companies, though neither contributed to research design.
Key Takeaways
- A two-year randomized trial of 958 adults aged 60+ found that a daily multivitamin slowed biological aging by approximately four months
- The effect was measured using epigenetic clocks, molecular markers tied to DNA methylation
- People already showing accelerated biological aging benefited the most
- Experts agree the results are promising but call for further research before drawing broad conclusions
- A daily multivitamin is not a magic fix — it works best alongside a healthy diet, regular exercise, and consistent sleep
