A groundbreaking study conducted by researchers at Mass General Brigham has unveiled compelling evidence that taking a daily multivitamin can decelerate the biological aging process in older adults over a period of two years. This randomized clinical trial, one of the largest of its kind, demonstrated measurable reductions in biological age markers, especially among participants who initially displayed accelerated biological aging compared to their chronological age. Published in the prestigious journal Nature Medicine, the findings shed new light on accessible and safe interventions with the potential to not only extend lifespan but also improve life quality during aging.
Biological aging, distinct from chronological age, captures the intricate molecular and cellular decline occurring in the body that accumulates over time. Unlike counting years, biological age reflects the physiological state of an individual’s tissues and organs, which can vary notably even between people of the same chronological age. In this study, researchers employed epigenetic clocks—innovative biomarkers rooted in DNA methylation patterns—to quantitatively assess biological aging. These epigenetic modifications regulate gene expression without altering the DNA sequence and shift predictably as we age, providing a quantifiable measurement of one’s biological age.
The research utilized DNA methylation data derived from blood samples of 958 healthy older adults who participated in the COcoa Supplement and Multivitamin Outcomes Study (COSMOS). Participants, averaging 70 years in chronological age, were randomized into four groups: daily multivitamin with cocoa extract, multivitamin without cocoa, cocoa without multivitamin, and placebo. This multi-arm design allowed isolated examination of multivitamin effects on epigenetic aging independent of cocoa extract supplementation. Blood samples were collected at baseline, after one year, and after two years, and analyzed against five different epigenetic clock algorithms known to track biological aging and mortality risk.
Results revealed participants receiving the daily multivitamin demonstrated a significant deceleration across all five epigenetic age measures compared to placebo-only participants. Of particular note were two epigenetic clocks strongly predictive of mortality; the multivitamin group experienced a statistically meaningful slowing of these aging markers. The overall effect size translated to approximately four months less biological aging over the two-year intervention period, an impressive outcome given the short timeframe and older participant cohort. Importantly, individuals who began the trial with biological ages exceeding their chronological age displayed the most pronounced benefits, suggesting a potential for targeted intervention among high-risk aging populations.
“This discovery, showing the impact of a common multivitamin on biological aging clocks, opens exciting avenues towards understanding how we can promote healthier aging at the molecular level,” explains senior author Dr. Howard Sesso. The study underscores a shift from purely longevity-focused strategies toward improving the quality of life by attenuating the biological processes that underlie age-related decline. The findings highlight the promise of widespread, cost-effective supplementation as a potential preventive measure against biological aging and its associated health consequences.
Epigenetic clocks operate by quantifying methylation changes at specific CpG sites throughout the genome. These sites regulate genetic activity, influencing gene expression patterns that evolve due to environmental factors, lifestyle, and intrinsic cellular processes. By capturing these changes, epigenetic clocks offer a dynamic biomarker system sensitive to interventions aiming to modify biological age independently from chronological time. The COSMOS trial’s robust use of multiple validated epigenetic clocks strengthens the validity and reproducibility of the observed effects.
While prior research has investigated micronutrients and antioxidants for their roles in mitigating cellular damage, this study is among the first large-scale, rigorously controlled trials to link multivitamin supplementation directly with quantifiable slowing of biological aging markers. The multivitamin formula used contained a blend of vitamins and minerals designed to address common deficiencies in older adults, including vitamin D, B vitamins, and antioxidants which collectively may influence DNA repair, inflammation, and mitochondrial health—factors rigorously implicated in aging pathways.
Researchers also emphasized the importance of assessing whether the observed biological age deceleration correlates with tangible clinical outcomes. Currently, COSMOS is examining potential downstream effects of multivitamin use on cognitive function, cancer incidence, and eye health, specifically cataracts. These secondary endpoints will clarify if molecular aging changes translate meaningfully into preserved organ function and reduced morbidity, bridging the gap between biomarker shifts and clinical relevance.
Notably, the trial also addressed the role of cocoa extract supplementation, which did not show significant impacts on epigenetic aging in this study’s parameters. This differentiation helps isolate the multivitamin as the key driver behind the slowed biological clock measures. Ongoing follow-up research aims to establish the durability of these effects beyond the intervention period, exploring whether biological aging markers remain favorably altered or rebound post-supplementation.
The COSMOS trial was funded by grants from the National Institutes of Health and supported by donations from nutrition-focused industry partners, including Mars Edge and Pfizer Consumer Healthcare. While these entities provided study pills and infrastructure support, the researchers maintained full independence over the trial design, conduct, and analysis, ensuring scientific rigor and minimizing potential conflicts of interest. The diverse team of investigators from Mass General Brigham and collaborating institutions combined expertise in epidemiology, preventive medicine, molecular biology, and clinical research.
The findings resonate profoundly in an era where population aging is accelerating globally, straining healthcare systems and economies. Strategies that can safely reduce the rate of biological aging hold promise for transforming the public health landscape—moving beyond disease treatment to proactive resilience enhancement. This trial demonstrates that a simple, daily multivitamin may represent a pragmatic tool with widespread applicability to promote molecular longevity among older adults.
In summary, this landmark study from the COSMOS randomized clinical trial reveals that multivitamin supplementation slows biological aging as measured by state-of-the-art epigenetic clocks. By reducing the pace of epigenetic aging by an estimated four months over two years, particularly in individuals with accelerated baseline biological age, the research highlights the potential for affordable, accessible interventions to improve healthy aging trajectories. Further investigations are poised to elucidate the mechanisms behind these effects and confirm their clinical significance. These findings ignite hope that commonplace supplements might form part of a broader strategy for extending healthspan in an aging society.
Subject of Research: People
Article Title: Effect of Daily Multivitamin-Mineral and Cocoa Extract Supplementation on Epigenetic Clocks of Biological Aging: 2-Year Findings from the COSMOS Randomized Clinical Trial
News Publication Date: 9-Mar-2026
Web References: http://dx.doi.org/10.1038/s41591-026-04239-3
References: Li S et al. “Effect of Daily Multivitamin-Mineral and Cocoa Extract Supplementation on Epigenetic Clocks of Biological Aging: 2-Year Findings from the COSMOS Randomized Clinical Trial.” Nature Medicine. DOI: 10.1038/s41591-026-04239-3
Keywords: Biological aging, epigenetic clocks, DNA methylation, multivitamin supplementation, randomized clinical trial, aging biomarkers, preventive medicine, COSMOS trial, mortality predictors, healthy aging
