Urolithin A is a compound produced in your gut when bacteria break down ellagitannins — plant polyphenols found in pomegranates, walnuts, and certain berries. Because gut bacteria vary so widely between people, only about 30–40% of adults naturally produce meaningful amounts of Urolithin A from diet alone. Supplementing it directly bypasses this limitation, delivering consistent levels regardless of your microbiome.

Urolithin A works by activating mitophagy — the body's built-in process for identifying and recycling old, damaged mitochondria so new, healthier ones can take their place. Mitochondria are the tiny power generators inside every cell, and as they age or get damaged, they become less efficient and can cause cellular stress. By keeping the mitochondrial pool cleaner and more functional, Urolithin A helps cells produce energy more effectively, which shows up as better muscle performance and less fatigue.

Urolithin A supplements are most commonly sold as capsules (typically 500–1000 mg) or as flavored powder drink mixes. The most clinically studied commercial form is Mitopure (Timeline Nutrition), a highly pure, standardized UA powder used in human trials. Bioavailability of supplemental UA is consistent and does not depend on gut microbiome composition, unlike dietary precursors.

• Muscle strength and weakness
• Exercise endurance and fatigue
• Age-related muscle loss (sarcopenia)
• Low cellular energy
• Inflammation
• Gut health and microbiome balance
• Metabolic health
• Healthy aging and longevity

• Age-accelerated muscle decline: sustained mitophagy activation may slow the rate of muscle loss associated with aging
• Chronic low-grade inflammation: by reducing dysfunctional mitochondria, may help prevent the persistent inflammation that underlies many age-related diseases

• Pomegranate (juice, seeds, whole fruit) — The richest dietary source of ellagitannins (punicalagins), the primary precursors your gut converts to Urolithin A — if your microbiome has the right bacteria.
• Walnuts — A significant source of ellagitannins and ellagic acid; regular walnut consumption is associated with detectable Urolithin A production in people with capable gut bacteria.
• Raspberries — Rich in ellagic acid and ellagitannins; among the highest-ellagitannin berries commonly eaten, supporting Urolithin A production.
• Strawberries — Contain moderate ellagitannin levels; a good daily contributor to the precursor pool for Urolithin A synthesis.
• Blackberries — Decent ellagitannin content; eating a variety of these berries together increases the likelihood of consistent Urolithin A production.

• Mild digestive discomfort (bloating or loose stools) — occasional and usually temporary
• Nausea — rare, typically at higher doses
• No significant effects on standard blood safety markers observed in trials at 500–1000 mg/day

• Recommended daily: 500–1000 mg per day (500 mg for general wellness; 1000 mg used in muscle performance trials)
• Best time of day: Morning is common and practical; timing relative to exercise does not appear critical based on current data
• With or without food: Can be taken with or without food; no significant difference in absorption has been demonstrated, though taking it with a meal may reduce any stomach sensitivity
• Time to effect: 4–8 weeks for measurable muscle endurance improvements; cellular effects may begin earlier
• How long to take it: Continuous daily use appears to be how it was studied; no evidence-based cycling protocol exists yet. Long-term safety data up to 4 weeks in formal trials is available; real-world use extends longer without reported issues