Can a Daily Multivitamin Really Slow Ageing?

The idea that a simple daily multivitamin could slow ageing sounds almost too convenient. For decades, supplements have been marketed as a shortcut to longevity, despite mixed scientific evidence.

A new study led by Harvard researcher Dr Howard Sesso has reignited the debate. Published in Nature Medicine, the research suggests that taking a daily multivitamin may modestly slow certain markers of biological ageing.

The findings are intriguing — but they also require careful interpretation.

TL;DR

• A Harvard-led trial found daily multivitamins slightly slowed biological ageing markers.
• The study followed nearly 1,000 adults over two years.
• Ageing was measured using DNA "epigenetic clocks".
• Participants taking multivitamins showed about four months less biological ageing.
• The effect was small and does not prove multivitamins extend lifespan.

What the Study Actually Looked At

The research analysed data from 958 healthy adults with an average age of around 70 who took part in the large COSMOS clinical trial.

Participants were randomly assigned to take:

• a daily multivitamin and mineral supplement
• a cocoa extract supplement
• both supplements
• or placebo

Blood samples were taken over two years to examine biological ageing markers.

Instead of measuring ageing simply by years lived, the researchers used DNA methylation "epigenetic clocks" — tools that estimate biological age by analysing chemical changes in DNA associated with ageing.

These clocks are increasingly used in longevity research because they reflect how the body is ageing at a cellular level.

What the Researchers Found

Participants who took the multivitamin showed a slower increase in biological age compared with those taking a placebo.

Across the two-year study period, the difference equated to roughly four months less biological ageing.

The effect was detected in two of the five epigenetic clocks used in the analysis, particularly those linked to mortality risk.

Interestingly, the benefit appeared strongest in individuals whose biological age was already higher than their chronological age at the beginning of the trial.

In other words, people ageing faster than expected seemed to benefit most.

What "Biological Age" Actually Means

The concept of biological ageing is central to understanding the findings.

Chronological age simply measures the number of years someone has lived. Biological age attempts to estimate how quickly the body is ageing based on molecular and physiological markers.

Epigenetic clocks measure changes in DNA methylation, a process that alters gene activity over time.

These changes accumulate with age and can reflect processes linked to:

• inflammation
• metabolic stress
• cardiovascular risk
• cellular damage

Because of this, biological age can differ significantly between individuals of the same chronological age.

Why Multivitamins Might Influence Ageing

The study does not prove a direct anti-ageing effect, but it offers several possible explanations.

Many older adults have mild deficiencies in nutrients such as vitamin B12, vitamin D, magnesium or folate. Even small deficiencies can affect cellular metabolism and DNA repair.

Multivitamins may help stabilise these micronutrient levels, supporting processes that maintain cellular health.

Another possibility is that micronutrients influence oxidative stress and inflammation, both of which contribute to biological ageing.

However, these mechanisms remain speculative.

The Effect Was Modest

While the results attracted attention, the magnitude of the effect was small.

A four-month difference in biological ageing over two years is measurable in research terms but unlikely to produce dramatic visible changes.

Experts also emphasise that slowing epigenetic ageing markers does not automatically translate into longer life or reduced disease risk.

The study also found no measurable effect from cocoa extract, which was tested alongside the multivitamin.

This reinforces the idea that the findings should be interpreted cautiously.

Previous Research on Multivitamins

The same COSMOS research programme has previously reported other potential benefits of multivitamins.

Earlier analyses suggested daily supplementation might help slow cognitive ageing or support memory in older adults, though the effects were modest and not seen in every outcome measured.

Across multiple trials, the pattern is similar: small but measurable effects in certain populations.

Importantly, these benefits tend to appear mainly in older adults, not younger populations with generally adequate nutrition.

Why Multivitamins Are Still Controversial

Despite occasional positive studies, multivitamins remain controversial.

Large population studies have often found little or no effect on:

• mortality
• heart disease risk
• cancer incidence

Many researchers argue that supplements offer the greatest benefit only when they correct genuine nutritional deficiencies.

For people with balanced diets rich in fruits, vegetables and whole foods, the additional benefit may be limited.

What the Study Does Not Show

The Harvard trial did not demonstrate that multivitamins extend lifespan or prevent major diseases.

It also does not prove that everyone should start taking supplements.

The participants were mostly older adults, and the trial lasted two years. Longer studies across more diverse populations would be needed to confirm broader benefits.

Even the researchers themselves emphasised that the results should be viewed as a starting point for further research rather than a definitive solution to ageing.

Where Lifestyle Still Matters Most

Perhaps the most important point is that ageing is influenced far more strongly by lifestyle than by supplements.

Factors consistently linked to slower biological ageing include:

• regular physical activity
• balanced diet
• adequate sleep
• stress regulation
• avoiding smoking

Micronutrients play a role in these systems, but they are only one part of a much larger picture.

At Vitae, the view is similar: supplements can support health in certain contexts, but they rarely replace the fundamentals. Our Reset Companion focuses on building sustainable daily habits — including sleep, nutrition and stress management — that form the foundation of long-term wellbeing.

FAQs

Do multivitamins slow ageing?

A recent trial suggests they may slightly slow certain biological ageing markers in older adults.

How large was the effect?

Participants showed about four months less biological ageing over two years.

Does this mean multivitamins increase lifespan?

No. The study did not measure lifespan or disease outcomes.

Should everyone take a multivitamin?

Not necessarily. The greatest benefit may occur in people with nutritional gaps.

Final Thoughts

The new Harvard-led research adds an interesting piece to the longevity puzzle.

Daily multivitamins appear capable of producing small changes in biological ageing markers, particularly in older adults whose bodies may be experiencing subtle nutritional deficits.

But the effect is modest and far from a shortcut to longevity.

Ageing is a complex biological process shaped by genetics, lifestyle, metabolism and environment. While supplements may help support certain pathways, they are unlikely to replace the foundational habits that influence health over decades.

The most powerful anti-ageing strategies remain surprisingly familiar: sleep well, eat broadly, move regularly and reduce chronic stress.

Multivitamins, at best, may simply support those systems — not transform them.

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