A daily multivitamin slowed biological aging by the equivalent of four months over two years in a large, rigorous study—surprising scientists who expected no measurable effect from such a simple intervention.
The findings reach from the COSMOS trial, published in Nature Medicine, which tracked 958 healthy participants averaging 70 years old. Half took a standard multivitamin-mineral supplement daily; the other half received a placebo. Over 24 months, researchers measured changes in five epigenetic clocks—biological markers that estimate cellular aging by analyzing DNA methylation patterns.
Those taking the multivitamin showed a consistent slowing across all five clocks, translating to roughly four months less biological aging than the placebo group over the study period. The effect was most pronounced on two clocks specifically linked to mortality risk, where the difference reached statistical significance.
Lead author Howard D. Sesso of Mass General Brigham in Boston cautioned against overinterpretation but noted the result suggests a viable, low-risk option for influencing biological aging. “A daily multivitamin may be a practical intervention to slow biological aging,” he said, emphasizing that the benefit likely stems from the combination of nutrients, not any single vitamin or mineral.
The study explicitly ruled out that one compound alone drives the effect. Researchers tested no individual ingredients; the formulation used was a broad-spectrum multivitamin designed to fill common dietary gaps. Sesso explained that the observed benefit may arise from correcting subtle deficiencies in otherwise healthy eaters whose diets still fall short of optimal micronutrient intake.
This nuance matters: the participants were not malnourished, but many likely had suboptimal levels of vitamins like D, B12, or zinc—nutrients whose long-term insufficiency accelerates cellular wear. The multivitamin didn’t enhance already-adequate levels; it brought marginal intakes up to sufficient thresholds, potentially reducing cumulative stress on repair mechanisms.
Critics will point out that four months over two years is modest in absolute terms. Yet in aging research, even small, sustained shifts in epigenetic pace can compound meaningfully over decades. If maintained, such a delay might translate to years of extended healthspan—the period of life free from chronic disease or disability.
More importantly, the study challenges the assumption that only complex lifestyle changes or pharmaceuticals can influence biological aging. It suggests that a widely accessible, inexpensive habit—taking a pill with breakfast—could nudge aging trajectories in a measurable direction for older adults with imperfect diets.
Still, the researchers stressed that multivitamins are not a substitute for foundational health behaviors. The effect was observed alongside, not instead of, exercise, sleep and balanced eating. For those already meeting nutritional needs through food, the benefit may be negligible—or nonexistent.
The findings also raise questions about supplement quality, and formulation. Not all multivitamins are equivalent; the COSMOS trial used a specific, rigorously tested product. Whether cheaper or differently composed versions yield similar results remains unknown and warrants further study.
Does this indicate everyone should start taking a multivitamin?
No. The study only showed a measurable benefit in adults around age 70 with likely dietary gaps. Younger people or those with nutrient-rich diets may see no effect—and could risk unnecessary intake of certain compounds like iron or vitamin A, which can be harmful in excess.
Could younger adults benefit from taking multivitamins now to slow aging later?
The study didn’t test this. It’s biologically plausible that maintaining optimal micronutrient levels early in life could slow cumulative damage, but there’s no direct evidence yet that multivitamins delay aging in people under 60.
