If you take a daily multivitamin - or you've been thinking about starting - a study published recently in Nature Medicine is worth your attention. Researchers found that older adults who took a daily multivitamin supplement for two years showed measurably slower markers of biological ageing compared with those taking a placebo. The effect was modest, there are important caveats, and the researchers are appropriately careful not to overclaim. But the quality of the evidence means this deserves to be understood properly.

Supplements and ageing: the UK context

In Britain, taking a daily supplement is far from unusual. According to Mintel's 2025 UK Vitamins and Supplements report, around 65% of over-55s use vitamin and mineral products regularly. Whether people are covering nutritional gaps, or simply trying to stay well for as long as possible, the underlying motivation is often the same: a sensible wish to age better. This study speaks directly to that instinct - and adds some of the strongest evidence yet that it may not be unfounded.

What is a biological age, and how do scientists measure it?

Your chronological age is simply how long you've been alive. Your biological age is something different - a measure of how your cells and tissues are actually ageing, which can diverge meaningfully from the number on your birth certificate. Scientists now measure this using tools called epigenetic clocks: patterns of chemical tags on DNA (called methylation marks) that change in relatively predictable ways as we get older. Different clocks capture different aspects of this process. Two of the most studied - PCGrimAge and PCPhenoAge - are linked to mortality risk, meaning people with higher readings on these clocks tend to have shorter life expectancy.

What this research set out to investigate, for the first time in a large-scale randomised controlled trial, was whether something as ordinary as a daily multivitamin could measurably shift those clocks.

What the study found

The research analysed blood samples from 958 healthy adults with an average age of 70, drawn from the wider COSMOS (COcoa Supplement and Multivitamin Outcomes Study) trial in the United States. Blood was taken at three points: enrolment, 12 months, and 24 months. Participants were randomly assigned either to a daily multivitamin supplement or a placebo.

Five epigenetic clocks were assessed. The daily multivitamin produced a statistically significant slowdown in two of them: PCGrimAge and PCPhenoAge - the two clocks most strongly associated with mortality risk. Across the two-year period, this translated to roughly four months of slower biological ageing compared with the placebo group.

The benefit was more pronounced in people who were already showing signs of accelerated biological ageing at the start of the study - meaning their biological age was higher than their chronological age. For those participants, the effect on PCGrimAge was substantially greater than in those whose ageing was progressing normally.

What to take from this

The COSMOS study matters because it's one of the first randomised controlled trials - the strongest type of clinical evidence - to directly examine whether a common, everyday supplement can influence the biology of ageing at a molecular level. The findings are encouraging rather than definitive, and the researchers are appropriately cautious about what can be concluded at this stage.

What the evidence does suggest is that for older adults whose diet may not be covering all nutritional bases, a daily multivitamin is unlikely to be without some benefit.

Keeping your nutritional foundations covered

If this study has prompted you to think about what you're doing to support your long-term health, our Newfoundland Multi-Vitamin Supplement offers a straightforward, convenient way to help cover your nutritional bases from home.