Four placebo-controlled trials. Some results held, some didn’t. Each claim graded.
Urolithin A is a compound your gut bacteria can make from foods like pomegranate — some people make plenty, many make little. It is sold as a supplement, mainly as Mitopure, an ingredient made by Amazentis and sold under its own brand, Timeline. The idea behind it: it helps cells clear out worn-out mitochondria, the parts that make energy.
The short answer: it has more real human trials than most supplements — four placebo-controlled trials between 2022 and 2026. The results are mixed. Several measures improved; several main outcomes did not. Three of the four trials were paid for by the maker; we show that next to every result.
No human trial has tested whether urolithin A slows aging or adds years of life. The longest trials ran four months. Lifespan results come from animal studies only.
Across these trials, side effects were no different from placebo at the doses tested (up to 1,000 mg a day, up to four months). Longer-term safety in people hasn’t been studied. Talk to a doctor first if you are pregnant, take other medicines, or have a medical condition.
The founder of this site is taking Mitopure and logging it on a schedule set in advance — on, off, then on again — measuring the one thing the trials found most often: muscle endurance. The log, including the weeks off.
Urolithin A (Mitopure) · evidence checked 2026-10-21
Grades are calculated from the studies listed, by fixed rules.
Both trials found better endurance — repetitions to fatigue in older adults’ hand and leg muscles; aerobic capacity in middle-aged adults — but neither was the outcome the trial was built around.
In older adults it was a main outcome and did not change. In middle-aged adults it improved as a secondary outcome. A tested main outcome that found nothing outranks a secondary result.
Leg strength rose about 12% in middle-aged adults — a secondary outcome. The trial’s main outcome, peak power on a bike, did not change.
Peak power output was the main outcome of the middle-aged trial and did not improve.
After 4 weeks, measures of T-cell types and their metabolism moved in the direction the trial predicted. These are lab measures of immune cells — the trial did not measure infections or illness.
Four weeks did not improve artery function (flow-mediated dilation) in middle-aged adults with obesity — the trial’s main outcome.