Large-scale randomized trials have found that multivitamin-multimineral (MVM) supplements and cocoa flavanols may benefit several age-related chronic conditions among older adults, but it remains unclear whether these two supplements directly slow the biological aging process. This prespecified ancillary study evaluated the 2-year effect of a daily MVM (Centrum Silver) and cocoa extract (500 mg cocoa flavanols per day, including 80 mg (-)-epicatechin) on five DNA methylation measures of biological aging (PCHannum, PCHorvath, PCPhenoAge, PCGrimAge and DunedinPACE) among 958 participants (482 women and 476 men) in the COcoa Supplement and Multivitamin Outcomes Study (COSMOS). Compared with placebo, daily MVM supplementation modestly reduced the rate of increase of second-generation epigenetic clocks, with a between-group difference in yearly change of -0.113 years (95% confidence interval (CI) -0.205 to -0.020; P = 0.017) for PCGrimAge and -0.214 years (-0.410 to -0.019; P = 0.032) for PCPhenoAge. MVM had a stronger effect on PCGrimAge among those with accelerated biological aging at baseline (-0.236 [-0.380 to -0.091]) compared with those with normal or decelerated biological aging (-0.013 [-0.130 to 0.104]; P = 0.018 for interaction). Cocoa extract did not have an effect on the five epigenetic clocks tested. Although the statistically significant but small effects of daily MVM supplementation on slowing biological aging are encouraging, additional studies are needed to determine the clinical relevance of daily MVM supplementation on epigenetic clocks and whether such effects can help explain the beneficial effects of MVM supplementation on aging-related chronic conditions.
© 2026. The Author(s), under exclusive licence to Springer Nature America, Inc.