A Multivitamin Can Slow Biological Aging, Just Not by Much

Does a multivitamin slow biological aging? For the first time there is a real randomized answer, and it is a cautious yes, with the emphasis on cautious. A large, well run trial found that a cheap daily multivitamin moved two of five biological aging clocks in the right direction over two years. The effect was small, it showed up on some clocks and not others, and it was concentrated in the people who were aging fastest to begin with.

That is a more interesting result than either the headlines or the eye-rollers will tell you. A multivitamin is the least glamorous thing on the longevity shelf, outsold a hundred to one by compounds with far thinner evidence. And yet it is the one supplement with this quality of trial behind a biological aging claim.

So it is worth reading the actual numbers, and being honest about how much a fraction of a clock-year is really worth.

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What Is an Epigenetic Clock?

Your chronological age is how many birthdays you have had. Your biological age is meant to capture how worn your body actually is, and the most studied way to estimate it is an epigenetic clock.

Over your life, chemical tags called methyl groups are added to and stripped from specific spots on your DNA. The pattern shifts in a surprisingly predictable way as you get older. An epigenetic clock is a statistical model trained on thousands of people that reads that methylation pattern and returns a number in years. Feed it the blood of someone whose pattern looks older than their birthdays suggest, and the clock reports an age ahead of their real one.

There is more than one clock, and this matters for everything below. Early clocks like Horvath and Hannum were tuned to predict chronological age. Newer ones, PCPhenoAge and PCGrimAge, were trained against disease and mortality, so they track health rather than just time, and they are the ones researchers now take most seriously. DunedinPACE is different again: instead of an age, it reports a pace, how fast you are aging right now. A clock is only a proxy. Moving one is not the same as living longer, and the people who build these clocks are the first to say so.

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The Science: Does a Multivitamin Slow Biological Aging?

The headline comes from one trial, and the honest reading keeps three things in view: which clocks moved, how far, and in whom.

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The COSMOS result: two clocks moved

• The Evidence: A prespecified ancillary study of the COSMOS trial followed 958 older adults for two years, randomized to a daily Centrum Silver multivitamin or placebo, and measured five epigenetic clocks. The multivitamin slowed the yearly rise of two of them. The between-group difference in annual change was -0.113 years on PCGrimAge (95% CI -0.205 to -0.020, P=0.017) and -0.214 years on PCPhenoAge (95% CI -0.410 to -0.019, P=0.032). The other three clocks did not budge. The trial’s cocoa extract arm moved none of the five.
• Read the study: Effects of daily multivitamin-multimineral and cocoa extract supplementation on epigenetic aging clocks in the COSMOS randomized clinical trial

Sit with the size of that. On PCGrimAge, the clock that best tracks mortality, the multivitamin group aged about a tenth of a clock-year less per year than placebo. Over the two years of the trial that adds up to a small fraction of a year on a model, not a felt difference you could point to in the mirror. It is real in the statistical sense, and it is tiny.

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The effect was biggest in people already aging fast

• The Evidence: The same analysis split participants by whether their biology was running ahead of their birthdays at the start. In people with accelerated aging at baseline, the PCGrimAge effect was -0.236 years per year (95% CI -0.380 to -0.091). In those aging normally or slowly, it was a flat -0.013 (95% CI -0.130 to 0.104), with a significant test for interaction (P=0.018).
• Read the study: Li et al., Nature Medicine 2026

This is the part worth carrying home. The benefit was not spread evenly. It landed almost entirely on the people whose clocks were already fast, and it essentially vanished in everyone else. A plausible reading is that a multivitamin helps most when something, a thin diet or an unmet need for a specific nutrient, has left room to help. For a well fed adult whose biology is tracking their age, this trial found close to nothing.

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The wider picture: what actually moves an aging clock

• The Evidence: A 2026 synthesis called TranslAGE harmonized 51 longitudinal intervention studies and recalculated the same clocks across all of them. Only pharmacological and lifestyle interventions significantly reduced epigenetic age on average, and drugs outperformed supplements as a category. DunedinPACE was the most responsive clock, while the older Horvath and Hannum clocks moved with no clear pattern, which is a direct warning against reading too much into a cheap first-generation clock test.
• Read the study: Responsiveness of epigenetic aging biomarkers to longevity interventions in humans

Against that backdrop the multivitamin result is a modest member of a modest group. The one supplement that holds up reasonably well on its own is fish oil: a post hoc analysis of the DO-HEALTH trial found that 1 gram of omega-3 a day slowed PhenoAge, GrimAge2 and DunedinPACE by roughly 2.9 to 3.8 months over three years. That is the same order of magnitude as the multivitamin, and it has its own evidence worth reading separately. The shared lesson is that supplements move these clocks a little, lifestyle and medicine move them more, and no single pill is doing heavy lifting.

One disclosure belongs here. Pfizer Consumer Healthcare, whose Centrum brand is now owned by Haleon, donated the pills for COSMOS, and FOXO Technologies donated the methylation testing. That does not sink a randomized, placebo controlled trial, but you should know whose product and whose assay produced the numbers.

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A Practical Guide: How to Use It

The dose is the simplest in this whole field: one Centrum Silver tablet a day, taken with food, which is exactly what COSMOS used. There is no loading phase, no timing trick, and no premium version to chase. The trial result is attached to this ordinary multivitamin, so a fancier or pricier blend is not buying you the evidence.

Who this is for. The signal was strongest in adults over 50 whose biological clocks were already running ahead, and that tracks with who tends to fall short on a nutrient or two: older adults, people eating a narrow diet, anyone who absorbs less as the gut ages. If that is you, a daily multivitamin is a cheap, low risk way to cover the gaps, and this trial is a mild point in its favor.

What not to do with it. Do not buy a consumer epigenetic clock test to check whether it is working. The TranslAGE analysis showed the older clocks those kits often rely on barely respond to anything, so a number that wobbles between two home tests tells you about noise, not about your aging. And a multivitamin does not replace the things that move the needle further, which remain the unglamorous basics: food, sleep, movement, and not smoking. It sits alongside the rest of the longevity shelf as a small, well evidenced add-on, not a centerpiece.

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Safety and Advice

A standard multivitamin at the label dose is one of the safer things you can take. The nutrients in Centrum Silver sit at or near everyday reference amounts, not megadoses, which is the main reason its safety record is calm. The real risk with any multivitamin is not toxicity, it is the quiet sense that a tablet licenses a worse diet. It does not.

A few specifics still matter. Fat-soluble vitamins like A, D, E and K build up in the body, so do not stack several products that each contain them without checking the totals. If you take blood thinners, the vitamin K in a multivitamin can interact, so tell your doctor. People with the iron storage disorder hemochromatosis, or anyone told to limit iron, should read the label, though the 50 and over formulations are usually low in or free of iron for this reason. As with anything new, if you have a medical condition or take prescription medicines, run it past a pharmacist or doctor first.

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The Bottom Line

Does a multivitamin slow biological aging? In the best trial we have, yes, by a small amount, on two of five clocks, and mostly in people who were aging fast to start with. It is the only supplement with a randomized result of this quality behind an aging-clock claim, which says as much about how thin the evidence is everywhere else as it does about the multivitamin. The effect is a fraction of a clock-year, not a fountain of youth.

If you are over 50 and your diet has gaps, a daily Centrum Silver is a few cents well spent and now has a little trial evidence on its side. Take it as cheap insurance against a shortfall, keep working on the sleep and the walking that move these clocks further, and treat anyone selling you a multivitamin as an anti-aging breakthrough with the skepticism the numbers deserve.

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This article is for educational purposes only and is not medical advice. Supplements can interact with medications and health conditions, so talk to a qualified healthcare provider before starting anything new.