Over the past two or three years, “longevity” — living not just longer but healthier — has become one of the topics we talk about most, and a whole shelf of supplements has suddenly become popular alongside it. You may already be taking some of these; others you might be hearing of for the first time. So what do they actually do, and how far does the science back them up? Let me be upfront from the start: with the evidence we have today, no supplement has been proven to extend human lifespan. Even so, it's worth looking honestly at the research behind each one.
Cellular cleanup and energy: Spermidine, NMN/NR, Urolithin A
Spermidine triggers autophagy — the body's cellular “housekeeping” — which is why it's one of the most-studied molecules in healthy ageing. People who get plenty of spermidine from food have shown lower mortality in observational studies, but that kind of data isn't enough to say spermidine “extends life”. Most of the claims about hair and skin still rest on small or early trials.
NMN and NR are precursors to a molecule called NAD+; think of them as fuel for your mitochondria. NAD+ levels fall as we age, and human studies show these supplements can raise it safely. But the results for concrete benefits like energy and metabolism are still inconsistent, and any lifespan effect remains at the animal and laboratory stage.
Urolithin A has the strongest clinical data of this group. Randomised trials in middle-aged adults have reported measurable improvements in muscle endurance and markers of mitochondrial health. Even so, the studies are short and small — it's too early to claim it “stops ageing”.
Antioxidant defence: Resveratrol, Ergothioneine, Astaxanthin
Resveratrol is the classic antioxidant we've discussed for years, found in fruits like grapes and blackberries. In the lab it activates sirtuins — the so-called “longevity genes” — but that effect is still only theoretical in humans. Comprehensive reviews find resveratrol offers modest benefits for a few metabolic markers (waist circumference, blood pressure in type 2 diabetes, cholesterol in people carrying extra weight) and no evidence of longer life. It's also poorly absorbed, and higher doses aren't more helpful.
Ergothioneine is the one you'll see called a “master antioxidant” on social media — that's mostly marketing language. It's a compound that accumulates in our cells and is abundant in mushrooms, and low levels have been linked to certain diseases. Human supplement trials, though, are still at an early stage.
Astaxanthin is a powerful antioxidant carotenoid. Human studies point to possible benefits for skin elasticity and moisture and for eye fatigue; the evidence is promising but the trials are small. One important note: astaxanthin is not a substitute for sun protection and won't replace your sunscreen.
Mind, stress and liver: Magnesium L-threonate, TUDCA, PEA
Magnesium L-threonate is a special form said to reach the brain, and it's often called “nootropic magnesium”. Small trials suggest possible benefits for sleep quality and cognitive performance, but the claim that it crosses the blood–brain barrier leans heavily on animal data, and human evidence is limited.
TUDCA is a bioactive bile-acid derivative. Most of the clinical research sits in the context of liver conditions; its safety and benefit for long-term general use in healthy people aren't established. It's very much a compound to consider under a doctor's supervision.
PEA (palmitoylethanolamide) is a natural lipid studied for chronic and neuropathic pain. Meta-analyses point to possible benefit for pain — so it stands out less as a “longevity” supplement and more as a compound aimed at pain and inflammation.
Gut health: Postbiotics
We've talked about probiotics and prebiotics for years; postbiotics are relatively new. Under the international ISAPP definition, a postbiotic is a “preparation of inanimate micro-organisms and/or their components that confers a health benefit”. Because they don't need to stay alive, they have an edge in shelf life and stability. Their effects on the gut barrier and immune balance are being researched — but the field is young and needs large human studies.
So where does that leave us? Some of these supplements are genuinely promising — a few, like urolithin A, have human data for muscle and mitochondria. But none extends life on its own, and much of the evidence is still short-term. The strongest “longevity” prescription is still on your plate: colourful vegetables and fruit, wholegrains, enough protein, good sleep, regular movement and managing stress. At best, a supplement is a small addition on top of that foundation — never a replacement for it.
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This article is for general information and isn't a substitute for individualised advice from your own doctor or dietitian. If you take medication, have a chronic condition, or are pregnant or breastfeeding, always check with your doctor before starting any supplement.
Merve Tığlı, Dietitian
Sources: Nutrition Journal — umbrella review of resveratrol supplementation on health outcomes (2026); Nature Aging — randomised trial of urolithin A on age-related immune decline (2025); Nature Reviews Gastroenterology & Hepatology — ISAPP consensus statement on postbiotics (2021); Advances in Nutrition — update on NMN human clinical trials and anti-ageing effects.