Longevity Supplements: What Human Trials Actually Show (2026)

What do longevity supplements claim?

Longevity supplements are sold on the idea that they target "hallmarks of ageing": tired mitochondria (the energy factories inside cells), "zombie" senescent cells that stop dividing but linger and inflame, and falling levels of molecules such as NAD+ and taurine. The pitch is that topping these up or clearing old cells will keep you younger for longer.

The claims usually made are:

• Urolithin A renews mitochondria (a process called mitophagy) and improves muscle strength and endurance.
• Spermidine switches on autophagy (the cell's recycling system) and protects memory.
• Fisetin and quercetin act as "senolytics" that clear senescent cells.
• Resveratrol (from red grapes) activates "longevity genes" called sirtuins.
• CoQ10 supports heart and muscle energy, especially for people on statins.
• Taurine declines with age, and topping it up slows ageing.

These ideas come from real lab science. The question is whether the pills do anything measurable in people.

What does the evidence show?

Urolithin A

This has the best human data of the group. In a four-month trial of 66 adults aged 65 to 90, 1,000mg a day improved hand and leg muscle endurance and lowered some blood markers of inflammation, but did not significantly improve the main outcomes (six-minute walk distance and muscle energy production). A second trial in middle-aged adults reported about 12% better muscle strength but missed its primary endpoint (peak power). Both trials were run or funded by Amazentis, the company that sells it. In Great Britain, the Food Standards Agency's novel food application for urolithin A was still under assessment by its expert committee when we checked.

Spermidine

The largest trial, SmartAge, gave 100 older adults with memory worries a wheat-germ spermidine supplement or placebo for 12 months. It found no difference in memory or biomarkers. Researchers noted possible hints in verbal memory and inflammation that need testing at higher doses. Several authors had links to a spermidine supplement company.

Fisetin and quercetin (senolytics)

Most senolytic research is in mice. The best human signal comes from small pilot studies using quercetin combined with dasatinib, a prescription cancer drug, not quercetin alone. A 2019 pilot in diabetic kidney disease showed fewer senescent cells in fat tissue after three days of treatment. A 2023 pilot in lung fibrosis mainly tested feasibility. For fisetin, a 2024 review describes promising lab and animal work but no completed trials showing benefit in healthy people.

Resveratrol

Resveratrol is poorly absorbed. A 2025 meta-analysis found blood levels after oral doses are low and studies are inconsistent. A 2020 review of side effects concluded that long-term human safety and drug interaction data are still lacking.

CoQ10

This is the one where the question is narrower and the data are better. A 2018 meta-analysis of 12 trials found CoQ10 reduced statin-related muscle pain, weakness and cramps. A 2025 meta-analysis found a smaller effect, with four of seven trials positive and three showing no change. There is no good evidence it slows ageing in people who are not on statins.

Taurine

A 2023 Science paper found taurine extended life in worms and mice and proposed that falling taurine drives ageing. A 2025 study in 137 men aged 20 to 93 found blood taurine did not fall with age and was not linked to muscle, strength or fitness, which challenges the idea in humans.

What about NMN?

NMN is not authorised as a food in Great Britain. We cover it separately in NMN and NAD+ supplements: do they work?.

Who might reasonably try them?

• Older adults who want to try urolithin A for muscle endurance, accepting the evidence is small and company-funded, and alongside (not instead of) strength training.
• People on statins with muscle aches who want to try CoQ10, after speaking to their GP, since the statin dose or type may also need reviewing.

For everyone else, the strongest evidence for a longer, healthier life is still regular activity, strength work, sleep, a mostly plant-rich diet, not smoking and keeping alcohol low.

Who should be careful?

• Anyone taking prescription medicines, especially blood thinners, diabetes or blood pressure medicines: ask a pharmacist before adding any of these, as interaction data are thin.
• Pregnant or breastfeeding women: none of these have been studied for safety in pregnancy.
• Anyone tempted by "DIY senolytic" protocols using dasatinib: this is a prescription drug with serious side effects and must not be self-sourced.
• People with kidney or liver disease.

If you want to try one: what to look for

• Third-party testing: look for Informed Sport, Informed Choice or NSF Certified for Sport, which test batches for contamination.
• Dose that matches the trials: for urolithin A, trials used 500mg to 1,000mg a day; for spermidine, about 1mg a day from wheat germ.
• No disease claims: UK law does not allow supplements to claim they treat or prevent disease. Claims of "reversing ageing" are a red flag.
• A time limit: decide in advance what change you expect and stop if it does not appear within three months.

Bottom line

Longevity supplements are built on interesting lab science, but human results are small, short and often industry-funded. Urolithin A and CoQ10 have narrow, modest evidence; the rest are Early. If you are spending money on healthy ageing, a gym membership or walking boots will buy you more evidence per pound than any capsule.