Does urolithin A improve muscle strength and endurance?

Small trials suggest urolithin A may modestly help muscle strength and endurance. A 2026 review found the evidence is still limited.

Published October 2026

Short answer

Small trials hint at better muscle strength and endurance, but the evidence is limited and mixed. Evidence grade C (Limited). Five small trials (236 people) with mixed results and a non-significant main walking outcome; downgraded for inconsistency and small total sample.

Key takeaways

Small trials in middle-aged and older adults found better muscle strength or endurance than placebo [1][2][3].
Pooling the walking-test results of two trials gave about 17 metres more in six minutes, but the range included zero [4].
The 2026 review rated the evidence low certainty and called the wider muscle results exploratory [4].
Most of the trials were sponsored or run by Amazentis, the company that sells urolithin A [2][1][5].

The short version

Urolithin A is a supplement that small trials suggest may help muscle strength and endurance in middle-aged and older adults [1][2][3]. A 2026 review of five trials found the evidence is still limited [4].

What the studies show

In a trial of 66 adults aged 65 to 90, endurance in two muscles rose more than with placebo after two months. The main walking test did not reach statistical significance [2].

In 20 resistance-trained men, 1 gram a day for eight weeks improved a maximal muscle contraction test and repetitions to failure more than placebo. Their bench press and squat gains were not statistically significant [3].

A trial in middle-aged adults reported muscle strength about 12% higher and clinically meaningful gains in aerobic endurance and the six-minute walk. Its main outcome, peak power, did not change [1].

Pooling two trials gave about 17 metres more in six minutes of walking, but the result could be zero [4].

In 42 distance runners at altitude, four weeks of the supplement did not improve their 3,000-metre time. It did lower perceived effort and a muscle damage marker after the test [5].

The nuances

The trial groups were small. The five randomised trials in the 2026 review had 236 people in total [4].

Some trials found no benefit. Four weeks did not change heart pumping measures in 10 people with heart failure [6]. It did not change artery widening in 50 adults with obesity [7].

A four-week trial in 50 middle-aged adults found changes in immune cell types. These are lab markers; the trial did not measure infections or illness [8].

Several authors of the main trials are employees of Amazentis, which sponsored the work, or hold patents on the compound [2][1].

What this means for you

The trials do not show how much to take or whether long-term use helps. No trial in this review ran longer than four months [2][1]. Talk with a doctor before starting it, especially if you take medicines, are pregnant, or have kidney or liver disease. No data were found for these groups.

Go deeper

Urolithin A — Small trials suggest urolithin A may modestly help muscle strength and endurance, especially in middle-aged and older adults.