Multivitamin Ageing: Two-Year Trial Recasts How Supplements May Shift Biological Clocks

The randomized COcoa Supplement and Multivitamin Outcomes Study tested whether routine supplementation could alter measures of biological ageing. The trial found that multivitamin use for two years produced small but statistically significant reductions on two epigenetic clocks — a result framed as a modest slowing of biological ageing.

Multivitamin Ageing: What Did the Trial Show?

In a prespecified ancillary analysis of the COSMOS randomized clinical trial, investigators evaluated 958 participants with an average age of about 70 for changes in five DNA methylation–based measures of biological age. Participants were assigned across four arms: daily multivitamin–multimineral (MVM) provision and cocoa extract, MVM and cocoa placebo, cocoa extract and MVM placebo, or two placebos. Blood samples taken at baseline, one year and two years were analysed for the five epigenetic clocks.

• Sample and design: 958 participants, average age ≈70, four-arm randomized design.
• Interventions: daily MVM (Centrum Silver in the trial details) and a cocoa extract (500 mg cocoa flavanols per day).
• Outcomes measured: five DNA methylation clocks including PCGrimAge and PCPhenoAge, plus DunedinPACE among others.
• Main finding: daily MVM modestly reduced the rate of increase on two second-generation clocks (PCGrimAge and PCPhenoAge).
• Magnitude: between-group yearly change differences were −0. 113 years for PCGrimAge and −0. 214 years for PCPhenoAge; the overall effect equated to roughly four months less biological ageing across two years.
• Cocoa extract: no detectable effect on any of the five clocks and no interaction with multivitamin use.

What Forces Shape These Results, and What They Mean?

The trial team highlighted several interpretive points. Dr Howard Sesso, epidemiologist and senior author at the Mass General Brigham department of medicine, emphasized that the findings do not imply universal prescription of multivitamins for older adults and that clinical relevance remains to be determined. The observed benefits were larger among participants who had faster biological ageing at baseline, a subgroup the authors suggest may have had greater pre-existing nutritional deficits; nutritional status may partly explain the differential responses. Funding for elements of the research included industry support, and the investigators called for further work to link epigenetic-clock shifts to meaningful health outcomes.

The results sit against a mixed evidence backdrop: earlier large trials have not shown extended lifespan benefit from daily multivitamins and, in one prior large study, were associated with potential harms. The COSMOS ancillary analysis frames a narrower question — whether broad-based supplementation alters markers tied to mortality risk and phenotypic ageing — and finds modest, clock-specific slowing rather than broad rejuvenation.

What Happens Next? Practical Takeaways and Uncertainties

For clinicians, researchers and older adults weighing supplement choices, the COSMOS epigenetic analysis supplies a measured signal: daily multivitamin–multimineral supplementation produced small reductions on two established epigenetic clocks over two years, while cocoa flavanol extract showed no effect. The study authors and ancillary commentators advise caution—larger samples, longer follow-up and linkage of epigenetic changes to clinical endpoints are required to determine whether these biomarker shifts translate into fewer age-related illnesses or improved quality of life.

Given the trial’s design and the modest magnitude of change, the most defensible interpretation is that multivitamin supplementation may benefit subgroups with accelerated biological ageing or nutritional deficits, but sweeping claims about reversing age or preventing major disease are not supported by these data. The scientific record from COSMOS points to modest biomarker change and clear avenues for further research rather than immediate practice overhaul. Endpoints that matter to patients and health systems must remain the priority as the field evaluates the promise and limits of multivitamin ageing