Does taking resveratrol make sense as an anti-ageing strategy?
For humans there is no convincing evidence that resveratrol supplements do anything against ageing; the animal research is interesting but has not yet translated into clinical practice, so hold off on supplements until better human data are available.
In yeast, worms and fruit flies, resveratrol extends lifespan in multiple studies. That sounds promising, but the effect does not automatically apply to humans: in roughly 40% of studies in those lower organisms the result was already absent, depending on species, dose and sex.
In mice the picture is mixed. The majority of mouse studies show no clear extension of lifespan. What resveratrol may do in mammals is offer some protection of health during life: fewer signs of cancer, diabetes and brain problems. But all of this still comes from animal research, not from studies in humans.
The biggest practical problem is absorption. After swallowing it, the body breaks resveratrol down so quickly that very little reaches the tissues where it is supposed to act. Reviews highlight this as a fundamental obstacle for supplements.
In the laboratory, resveratrol inhibits certain pro-inflammatory substances and activates a protein that is also triggered by eating less, which in animals is associated with a longer lifespan. Whether those mechanisms also lead to health benefits in humans has not yet been demonstrated.
In humans, clinical studies are scarce and their outcomes are unclear. Resveratrol appears to be well tolerated in the available studies, without serious side effects, but how safe it is at high doses over the long term has barely been investigated. There is currently no evidence that taking it slows ageing or extends lifespan in humans.
All sources are reviews (no meta-analyses or randomised trials). None of the underlying clinical studies in humans was provided directly as a source. The strength of evidence for effects in humans is therefore limited.
Do multivitamins help with healthy ageing?
Daily multivitamins appear to offer some protection for the memory of older adults, but for most other aspects of healthy ageing the effect is small or absent. If you have a confirmed deficiency in vitamins or minerals, supplementing is certainly worthwhile; do not regard it as a miracle remedy.
Does quercetin work against ageing and inflammation?
Quercetin shows promising signals in the laboratory and in animals, but in humans there is not yet solid evidence. Taking supplements on the basis of this early-stage research gets too far ahead of the science.
Does stem cell therapy work against ageing in humans?
For physical frailty in older adults there is one positive study in people. For all other ageing-related applications it is too early for firm conclusions. Stem cell therapy cannot yet be considered a proven anti-ageing treatment.
Does taurine work against ageing?
Taurine supplements as a means of slowing ageing have not yet been proven in people. The results from animal studies are promising and sound plausible, but research in people is still entirely lacking.
Does spermidine actually do anything against ageing?
Spermidine has a well-supported mechanism of action and promising results in animal research, but evidence that a supplement actually works in humans is still lacking. Getting more spermidine through food, such as legumes and wholegrain cereals, is a safe and sensible choice.
Does alpha-ketoglutarate work against ageing?
In animal research AKG clearly extends lifespan, but solid evidence in humans is still lacking. Wait for the results of the ongoing randomised trial before drawing conclusions or taking supplements.