Daily multivitamin use may slow biological aging: COSMOS trial results
massgeneralbrigham.org44 points by hhs 3 days ago
44 points by hhs 3 days ago
Partially funded by entity related to manufacturer of daily multivitamins. Study was in people over 60 average age 70 if I recall. I didn't care enough to look, but the question I'd ask is how were the people who died during the study accounted for in the "biological aging testing?"
While that is true, a fact that increases the credibility of the published results is that the study also obtained a negative result.
Besides the multivitamin supplement, they also tested cocoa extract, for which similar effects had been claimed, and for that they did not find any effect.
The fact that the multivitamin supplement had effect is plausible. Presumably a significant number of the participants did not eat a perfect diet that would supply all vitamins in adequate quantities, so for those, taking a multivitamin supplement compensated whatever vitamin deficiency their diet might have had.
Such a positive result does not demonstrate that you need to buy a vitamin supplement, it just demonstrates that it is desirable to eat healthy food. However, there are circumstances when a vitamin supplement may be cheaper or more convenient than buying and eating enough food of an appropriate type.
For example, I take a vitamin supplement from time to time, but that is only because I have a sedentary lifestyle, working at a computer, so I must eat relatively little, otherwise I would gain weight immediately. When you eat little, it is difficult to compose a menu that will provide enough vitamins without also providing too much energy.
Multi vitamin use has been studied A LOT with respect to all cause mortality, where it consistently has no statistical effect (or a slightly negative effect). So, to me, "biological aging" seems a way to hack for effects to advertise. Does the average consumer understand that reduced "biological aging" does NOT mean you will live longer? Because if it did, they would be saying THAT. Centrum (study sponsor) is already creating advertising based on this study.
> Partially funded by entity related to
That doesn't mean the study is wrong... It just means if results were different maybe it wouldn't be published.
In biological age clocks, the kind COSMOS used, skin is one of the primary tissues researchers use to validate them. Epigenetic methylation patterns in skin cells are among the most studied markers precisely because skin is accessible and responds visibly to the same aging processes the clocks are trying to measure from blood.
The COSMOS trial gives everyone the same pill and measures a whole-body average signal from blood samples. It can't tell you which vitamin drove the effect or where in the body it's acting. It's a limitation of what a broad systemic intervention can tell you. The more targeted work is happening at the tissue level.
In skin specifically, L'Oréal and UC San Diego looked at 1,000+ subjects in 2024 and found that bacterial diversity in the skin microbiome correlates directly with both chronological age and wrinkle depth. They're building these as actual measurable aging biomarkers. Unilever's 2025 study also showed that people whose facial microbiome had higher Acinetobacter and lower Staphylococcus aureus were read as biologically 5–7 years younger. Many other companies are also researching biomarkers for skin anti-aging, and now the longevity trend is being seen in the food industry as well.
Microbiome as a modifiable aging clock is where the real specificity is starting to come from. I work in this space, and we recently mapped where this research is heading. We also did a session exploring the underlying science if you want to go deeper: https://greyb.com/resources/skin-microbiome-beauty/
L'Oréal Study: https://www.frontiersin.org/journals/aging/articles/10.3389/... Unilever Study: https://academic.oup.com/bjd/article/193/Supplement_2/ii24/8...
Note the use of may
From Harvard: https://news.ycombinator.com/item?id=47319478
Daily multivitamins are the quintessential Pascal Wager, in my opinion. There is no reason not to take them. At worst, you'll just urinate the excess out; at best, you'll supplement missing vitamins in your diet.