Can a Multivitamin Really Slow Ageing?

We all age. That much is certain. But what if the speed at which your body ages could be dialled back — even slightly — with something as simple as a daily multivitamin?

That’s the tantalising question raised by a wave of recent research, including findings from one of the largest clinical trials of its kind. The results are promising, if modest — and they come with important caveats.

Here’s what we know so far.

Key Takeaways

• A major clinical trial (COSMOS) found that taking a daily multivitamin for two years slowed biological ageing by roughly four months in older adults.
• The benefits were strongest in people whose bodies were already ageing faster than their actual years.
• Separate studies from the same trial found multivitamins may also support memory and cognitive function.
• However, large observational studies have found no link between daily multivitamin use and living longer.
• Multivitamins are not a magic pill — they work best as a way to fill nutrient gaps alongside a balanced diet.
• The NHS advises that most people can get all the nutrients they need from a varied diet, though certain groups may benefit from supplements.

Your Body’s Hidden Clock: Biological Age vs Chronological Age

Your chronological age is simply the number of years since you were born. But your biological age tells a different story. It reflects how much wear and tear your body has actually experienced at a cellular level.

Two people born on the same day can have very different biological ages. Factors like diet, stress, sleep, exercise, and genetics all play a role. Scientists now measure biological age using something called “epigenetic clocks” — tools that track tiny chemical changes in your DNA over time. These clocks can estimate how quickly your body is ageing and even predict mortality risk.

Understanding the gap between your chronological and biological age is at the heart of modern longevity science.

The COSMOS Trial: A Landmark Study

The COcoa Supplement and Multivitamin Outcomes Study (COSMOS) is one of the most rigorous clinical trials to investigate the effects of daily multivitamin use on ageing. Run by researchers at Harvard and Mass General Brigham, the trial involved thousands of older adults across the United States.

In a key analysis published in Nature Medicine in March 2026, scientists examined blood samples from 958 participants with an average age of 70. Half took a daily multivitamin (Centrum Silver); the other half took a placebo. After two years, the researchers measured changes across five different epigenetic clocks.

The results were noteworthy:

• People taking the multivitamin showed slowing across all five biological ageing markers.
• Two of the clocks — known as PCGrimAge and PCPhenoAge, which are linked to mortality risk — showed statistically significant slowing.
• The overall effect amounted to roughly four months less biological ageing over two years. In simple terms, after 24 months, participants’ cells had aged the equivalent of about 20 months.
• Those who were already biologically older than their actual age at the start of the trial benefited the most.

As senior researcher Howard Sesso put it: “There is a lot of interest today in identifying ways to not just live longer, but to live better.”

Beyond Ageing: Cognitive Benefits Too

The COSMOS trial didn’t stop at biological age. Separate analyses from the same study found that daily multivitamin use also supported brain health.

In the COSMOS-Web study, over 3,500 older adults who took a daily multivitamin showed meaningful improvements in verbal memory after one year — an effect that was sustained over three years of follow-up. Researchers estimated the cognitive benefit was equivalent to reversing roughly three years of age-related memory decline.

A further review published in early 2026 confirmed that multivitamin supplementation was most helpful for memory and global cognition, particularly in those with existing nutritional gaps or mild cognitive impairment.

How Might Multivitamins Work?

Scientists are still working out exactly why a simple multivitamin might slow biological ageing. The leading theory is straightforward: many older adults have subtle nutrient deficiencies — even if they eat reasonably well.

A daily multivitamin containing vitamins A, C, D, E, K, B-complex vitamins, and minerals such as magnesium, zinc, and calcium may help to:

• Fill nutritional gaps that become more common with age
• Reduce oxidative stress and inflammation, both of which drive cellular ageing
• Support DNA repair and healthy gene expression
• Maintain cognitive function by nourishing key brain structures

The NHS notes that most people should be able to get the nutrients they need from a varied and balanced diet. However, certain groups — including older adults, those with restricted diets, and people with specific health conditions — may benefit from a supplement.

The Other Side: Why Caution Is Still Warranted

It’s important to keep these findings in perspective. Not all the evidence points in the same direction.

A large 2024 cohort study tracking nearly 400,000 adults over 20 years found that daily multivitamin use was not associated with living longer. In fact, it suggested a small (4%) increase in all-cause mortality — though researchers cautioned that this finding needs to be replicated before drawing firm conclusions.

A meta-analysis published in Ageing Research Reviews in early 2026 echoed this mixed picture: while multivitamins showed benefits for cognition and some health markers, no clear benefit was found for overall mortality, COVID-19 outcomes, or visual acuity.

Key points to bear in mind:

• The COSMOS epigenetic findings, while encouraging, involved a relatively small sample (958 people) and a short follow-up period (two years).
• Slowing an epigenetic clock does not necessarily mean you will live longer or avoid disease — more research is needed to confirm that link.
• Only two of the five clocks showed statistically significant changes; three did not.
• Diet, exercise, and sleep remain the most well-evidenced pillars of healthy ageing.

As one independent expert noted: “The finding is interesting, but it is still far from showing that multivitamins broadly slow ageing or improve longevity.”

Practical Takeaways: What Should You Do?

If you’re already taking a daily multivitamin, the latest evidence suggests there’s good reason to continue. If you’re not, it may be worth discussing with your GP — especially if you’re over 60 or have dietary gaps.

Here’s a sensible approach:

• Prioritise a balanced diet first. No pill replaces the benefits of whole foods, fibre, and a Mediterranean-style eating pattern.
• Consider a multivitamin as an insurance policy, not a substitute. It may help plug gaps in your nutrition, especially as you age.
• Focus on the fundamentals: regular movement, quality sleep, stress management, and strong social connections.
• Speak to a healthcare professional before starting any new supplement, particularly if you take medication or have underlying conditions.
• Don’t chase hype. The science is promising but still evolving. A measured, evidence-based approach is always the wisest path to living longer and living better.

The Bottom Line

The idea that a humble multivitamin could slow the ticking of your biological clock is genuinely exciting — and for the first time, we have data from a rigorous clinical trial to support it. But it’s one piece of a much larger puzzle.

True longevity isn’t found in a single pill. It’s built through daily habits, smart choices, and a commitment to looking after both body and mind. A multivitamin might just be one small — but meaningful — part of that journey.