Urolithin A is a supplement the longevity world is increasingly talking about. There has been several promising human trials with several more ongoing and reporting soon. Here is a summary of those studies:
1. The ATLAS Trial (Muscle Strength & Endurance in Middle-Aged Adults)
Published in 2022 in the journal Cell Reports Medicine, this is the original high profile trial. It tested the effects of Urolithin A on healthy but overweight, middle-aged adults (ages 40-65) who did not exercise regularly.
- The Design: Participants were given either 500 mg or 1,000 mg of UA daily, or a placebo, for four months.
- The Findings: Without changing their diet or exercise habits, the group taking 1,000 mg of UA saw a 10-12% increase in muscle strength (specifically in the hamstrings). They also improved their aerobic endurance, walking 33 meters further in a 6-minute walk test compared to the placebo group.
- Inflammation: The study also found a significant reduction in inflammatory biomarkers, including C-reactive protein (CRP), suggesting that clearing out damaged mitochondria reduced systemic inflammation.
2. The Older Adult Muscle Endurance Trial
Also published in 2022 (in JAMA Network Open), this trial focused on an older demographic—adults aged 65 to 90.
- The Design: Participants took 1,000 mg of Urolithin A daily for four months.
- The Findings: While it did not show the same dramatic increases in peak muscle strength as the middle-aged cohort, it significantly improved muscle endurance. Participants taking UA showed improved mitochondrial efficiency in their skeletal muscles, allowing their muscles to resist fatigue longer during exercise.
3. The Immune Aging Trial (Counteracting Immune Decline)
Moving beyond muscle tissue, this a trial investigated the "muscle-immune axis." As we age, our immune cells, specifically T-cells, lose their mitochondrial efficiency and become exhausted, leading to a weaker immune system.
- The Design: In this randomized, placebo-controlled trial, 50 healthy middle-aged adults received 1,000 mg of Urolithin A daily for four weeks.
- The Findings: Published recently, this study showed that UA essentially rejuvenated the immune system. It expanded the pool of "naive" CD8+ T-cells (youthful immune cells ready to fight new infections) and reduced the number of terminally exhausted immune cells. It did this by boosting the fatty acid oxidation capacity—the energy production—within the immune cells themselves.
4. Upcoming/Ongoing Trials (ATLAS 2)
ATLAS 2 trial (expected to conclude in late 2026). This is a confirmatory, double-blind, placebo-controlled study designed to further validate the effects of the Urolithin A supplement on muscle strength and performance in healthy middle-aged adults.
The thesis across these trials is that aging is largely driven by mitochondrial dysfunction. By using Urolithin A to stimulate mitophagy (the clearing of dead and damaged mitochondria), you can improve the function of highly energy-dependent tissues, primarily skeletal muscle and immune cells.
5. University of Oklahoma Trial: Blood Flow and Obesity
This study is looking at how Urolithin A might protect the vascular system and potentially reduce the risk of cognitive decline in middle-aged adults who are overweight.
- Trial ID: NCT05921266 (Updated June 2025 and reporting in 9-months)
- Location/Sponsor: University of Oklahoma
- The Goal: To determine if supplementing with Urolithin A improves endothelial function (the health of blood vessel linings) and cerebrovascular function (blood flow to the brain). The underlying theory is that clearing out damaged mitochondria may improve nitric oxide availability, allowing blood vessels to dilate more efficiently.
- Who is participating: Middle-aged adults (40-64 years old) classified as obese (BMI ≥ 30).
- What they are measuring: Participants take UA daily for 4 weeks. Researchers are measuring changes in blood flow on the surface of the hand, reactive hyperemia (how well blood vessels open up after being restricted), and homeostatic cerebral blood flow.
