Double Wood Supplements markets a standalone Urolithin A capsule aimed primarily at adults interested in muscle health, mitochondrial function, and healthy aging. Urolithin A is not a herb or synthetic drug: it is a postbiotic compound that the human body can generate from ellagitannins, a class of polyphenols abundant in pomegranates, walnuts, and certain berries. The catch is that production depends heavily on an individual’s gut microbiome, meaning many people produce little or none on their own.
This review examines the clinical and mechanistic science behind urolithin A to help you assess whether Double Wood’s supplement deserves a place in your routine. We draw only on peer-reviewed evidence and avoid the marketing language common to this product category. Nothing here constitutes medical advice.
Key Takeaways
- Urolithin A is proposed to activate mitophagy, the cellular process of clearing damaged mitochondria, but most of that evidence is from cells, worms and mice, and the 2020 and 2026 sarcopenia reviews note there is no accepted therapy for muscle aging [11][12][13][14][1].
- A 2022 JAMA Network Open RCT in 66 older adults reported no significant improvement versus placebo on its primary endpoints (walking distance and muscle ATP production); muscle endurance, a secondary endpoint, was higher on urolithin A [2]; an 8-week trial in 20 male athletes reported more repetitions to failure but, by its authors’ own statement, did not show improved muscle strength, and C-reactive protein rose within the urolithin A group [3].
- Double Wood offers a lower-cost urolithin A option, but most clinical trials used Mitopure, a different commercial preparation: direct efficacy comparisons cannot be made with confidence.
- Not everyone converts dietary ellagitannins into urolithin A efficiently; supplementation is most likely to benefit those who are poor endogenous producers or have limited intake of ellagitannin-rich foods.
- Research beyond muscle health, including neurological and immune findings, remains largely preclinical and should not be interpreted as established human benefits.
What Is Urolithin A and Why Is It Hard to Get from Food?
Urolithin A is produced when gut bacteria metabolize ellagitannins and ellagic acid from foods like pomegranate, raspberries, and walnuts. The pathway requires specific bacterial strains, and studies suggest that only a subset of adults in Western populations are efficient urolithin A producers. Research into food-based precursors continues: a 2026 crossover trial found that acid hydrolysis of jaboticaba peel and seed powder significantly increased urolithin excretion in participants, suggesting that food processing methods can meaningfully influence how much urolithin the body ultimately receives [4]. Separately, microencapsulation of ellagic acid has been explored as a strategy to improve its solubility and biotransformation into urolithins [5].
Because dietary conversion is unreliable, direct supplementation with purified urolithin A has become the focus of clinical research. Double Wood offers a capsule form, allowing consistent dosing independent of gut microbiome status. This is the same rationale behind pharmaceutical-grade urolithin A products like Mitopure, though Double Wood positions its product at a significantly lower price point.
The Core Mechanism: Mitophagy and Mitochondrial Renewal
The central claim for urolithin A supplementation rests on its ability to induce mitophagy: the selective process by which cells identify and clear damaged or dysfunctional mitochondria. Over time, accumulation of impaired mitochondria is associated with reduced cellular energy output, increased oxidative stress, and age-related decline in tissues with high energy demands, particularly skeletal muscle. A 2025 review in Nutrition Research Reviews examined the distinct roles of urolithin A and spermidine in mitophagy and autophagy, a narrative review that treats urolithin A as a mitophagy inducer; it is a review opinion, not a head-to-head trial, and in a mouse liver study protection persisted with mitophagy blocked [14][1].
Research note: One day after drinking a glass of pomegranate juice, 33% of healthy American adults could not convert it to urolithin A and 27% converted poorly (the rest were high converters) [16].
Mitochondrial turnover is not merely a muscle story. A 2023 Nature Aging study showed that inducing mitochondrial recycling could revert age-associated decline in hematopoietic and immune system function in preclinical models [6], suggesting that mitophagy-inducing compounds may have relevance across multiple tissue systems. A 2024 review in Sports Medicine also identified mitochondria as a central nutritional target for preserving muscle health and physical function during aging [7], reinforcing the mechanistic rationale for compounds like urolithin A.
Clinical Evidence: Muscle Endurance and Strength
The most cited human trial is a randomized clinical trial published in JAMA Network Open in 2022, which evaluated urolithin A supplementation in older adults. Participants receiving urolithin A showed improvements in muscle endurance: specifically contractions to fatigue in a hand muscle and a leg muscle, alongside lower plasma acylcarnitines, ceramides and C-reactive protein, compared to placebo. The trial tested a single dose of 1000 mg per day against placebo [2]. The trial was randomized and placebo-controlled, but it was small (66 adults), enrolled only White participants from the Seattle area, and was funded by the maker of Mitopure; its authors call the results preliminary [2].
More recently, an 8-week randomized, double-blind, placebo-controlled study in male athletes undergoing resistance training found more repetitions to failure and higher isometric strength than placebo, but no significant gain in 1RM bench press or squat, and C-reactive protein rose within the urolithin A group [3]. It is worth noting that this study used an athletic population, which differs substantially from the older-adult cohort in the JAMA trial; results should not be uncritically generalized across these groups.
Taken together, the human clinical data on muscle outcomes is more substantive than most supplements in this space, but the evidence base remains limited in scope. Long-term trials, larger and more diverse cohorts, and studies including women and non-athlete populations are needed before broad conclusions can be drawn.
Two details worth knowing: the JAMA trial was funded by the maker of Mitopure, and walking distance improved in both the placebo and urolithin A groups, which the authors suggest may reflect higher activity from taking part. A 2024 systematic review of five human studies (250 people) found no effect on physical function [2][15].
Emerging Research: Beyond Muscle and Mitochondria
Urolithin A research is expanding into new areas. A 2025 animal study published in Nutrients found that urolithin A exhibited antidepressant-like effects by modulating the AMPK/CREB/BDNF signaling pathway [8]. This is early-stage preclinical data and does not translate directly to a recommendation for humans, but it points to possible neuroactive properties that may be worth watching in future research.
In ophthalmology, researchers have identified mitochondrial and microtubule defects in exfoliation glaucoma [9], and mitophagy-inducing compounds are being discussed as potential investigational agents in that context. This research is preliminary and does not suggest that urolithin A supplementation prevents or treats glaucoma, but it illustrates how mitochondrial biology intersects with a broad range of tissue systems beyond muscle.
A 2025 randomized controlled trial on multi-species synbiotic supplementation found that certain probiotic formulations enhanced gut microbial diversity, increased endogenous urolithin A production alongside butyrate, and reduced systemic inflammation markers [10]. This raises a practical question: could improving gut microbiome composition serve as a complementary or alternative route to raising urolithin A levels without relying solely on direct supplementation?
Double Wood Urolithin A: Product Specifics and Value Comparison
Double Wood Supplements offers urolithin A in 500 mg capsules, typically sold in bottles of 60 capsules. Their pricing is substantially lower than Mitopure (the branded, pharmaceutical-grade urolithin A preparation used in most published clinical trials) making it one of the more accessible options on the market. However, it is important to understand that most human trials were conducted specifically with Mitopure, a highly purified and well-characterized compound. Double Wood’s product has not been independently tested in clinical trials, and whether purity, bioavailability, and manufacturing standards are equivalent to those used in published research is not established.
Double Wood does provide third-party testing documentation and publishes certificates of analysis, which is a meaningful sign of quality-assurance effort relative to many supplement brands. The company is US-based and has a generally transparent reputation in the supplement space. Consumers should understand, however, that they are extrapolating from studies conducted with a different commercial preparation, which introduces an uncertain degree of variability in expected outcomes.
Who Might Benefit and What to Realistically Expect
Based on available evidence, urolithin A supplementation has the strongest support for adults over 50 experiencing age-related muscle decline or reduced exercise capacity, particularly those who are poor endogenous urolithin A producers. The JAMA 2022 RCT [2] and the athletes’ trial [3] each found some secondary-measure gains, but both are small studies and neither showed clear improvement on its main measures [2][3] and is not a substitute for exercise, adequate protein intake, or medical care.
People with robust, diverse gut microbiomes who already consume ellagitannin-rich foods regularly may produce sufficient urolithin A endogenously. For these individuals, supplementation may offer less incremental benefit. Conversely, those on restrictive diets, experiencing gut dysbiosis, or with reduced microbial diversity may stand to gain more from direct supplementation. The synbiotic trial finding that certain probiotic formulations raised endogenous urolithin A levels [10] suggests that gut health interventions are also worth considering as a parallel strategy.
🛒 Where to Buy Urolithin A
- Timeline Mitopure SoftgelsClinically studied
softgels, 500 mg/day: The clinically studied form (Amazentis); used in the human trials. - Pure Encapsulations Renual
caplique capsules, 250 mg Mitopure Urolithin A/serving (with resveratrol + CoQ10): adds resveratrol and CoQ10, a combination the published urolithin A trials did not test. - ProHealth Longevity Urolithin A
capsules, 500 mg: Longevity-focused brand, often higher dose. - Double Wood Urolithin A
capsules, 250-500 mg: Budget-friendly, widely available, COA on request.
As an Amazon Associate we earn from qualifying purchases. Prices and availability vary; verify dose and third-party testing before buying.
A Note on the Evidence
The human clinical evidence for urolithin A is promising but still limited in population diversity, study duration, and independent replication, and most trials used a pharmaceutical-grade preparation (Mitopure) rather than commercially available supplements like Double Wood. This supplement is not a treatment for any condition; people with chronic illness, those taking medications, or those who are pregnant or breastfeeding should consult a physician before use.
Frequently Asked Questions
What does urolithin A actually do in the body?
Urolithin A primarily induces mitophagy, a process by which cells selectively break down and recycle damaged mitochondria. A 2025 review confirmed its distinct role as a mitophagy inducer with specific implications for dietary supplementation [1]. By promoting mitochondrial turnover, it is thought to support cellular energy efficiency, particularly in high-demand tissues like skeletal muscle.
Is there real human clinical trial evidence for urolithin A?
Yes, though the evidence base is still developing. A randomized clinical trial in JAMA Network Open found that urolithin A improved muscle endurance and plasma biomarkers in older adults at a dose of 1000 mg per day [2]. An 8-week double-blind trial in male athletes also found improvements in endurance, inflammation, and oxidative stress markers [3]. These are meaningful trials, but more diverse and longer-term studies are needed.
How is Double Wood's urolithin A different from Mitopure?
Mitopure is a patented, pharmaceutical-grade urolithin A preparation developed by Amazentis and used in most published human clinical trials. Double Wood offers a generic urolithin A at lower cost. While both contain the same compound, Double Wood’s formulation has not been independently validated in clinical trials, and differences in purity or bioavailability may exist. This is not a disqualifier, but it means that efficacy extrapolation from trial data carries more uncertainty.
Can you get enough urolithin A from food alone?
It depends on your gut microbiome. Urolithin A is produced by gut bacteria from ellagitannins in foods like pomegranates and walnuts, but conversion efficiency varies widely. Processing can help: acid hydrolysis of jaboticaba peel was shown to increase urolithin excretion in a clinical crossover trial [4]and synbiotic supplementation has been shown to raise endogenous urolithin A production alongside gut microbiome improvements [10]. However, many people lack sufficient gut bacteria for reliable conversion, making direct supplementation a practical consideration.
Are there benefits of urolithin A beyond muscle health?
Early research suggests possible effects on immune function and aging: a 2023 Nature Aging study found that inducing mitochondrial recycling reverted age-associated immune decline in preclinical models [6]. A 2025 animal study also reported antidepressant-like effects via the AMPK/CREB/BDNF pathway [8]. These findings are preclinical and should not be interpreted as proven human benefits at this stage.
What dose of urolithin A is supported by research?
The JAMA 2022 trial tested 1000 mg per day of urolithin A against placebo for four months, with improvements in muscle endurance and plasma biomarkers of cellular health [2]. Double Wood’s standard capsule is 500 mg. Since Double Wood’s preparation was not used in these trials, dosing equivalence cannot be assumed with certainty. Follow product labeling and discuss dosing with a healthcare provider before starting.
References
- Borsky P et al. Distinct roles of urolithin A and spermidine in mitophagy and autophagy: implications for dietary supplementation. Nutrition research reviews (2025). PMID 41404767
- Liu S et al. Effect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial. JAMA network open (2022). PMID 35050355
- Zhao H et al. Assessment of Urolithin A effects on muscle endurance, strength, inflammation, oxidative stress, and protein metabolism in male athletes with resistance training: an 8-week randomized, double-blind, placebo-controlled study. Journal of the International Society of Sports Nutrition (2024). PMID 39487653
- Bizarelo R et al. Acid hydrolysis of jaboticaba (Myrciaria jaboticaba) peel and seed powder increases urolithin excretion in a cross-over clinical trial with normoweight subjects. Food & function (2026). PMID 42023516
- Pınarbaşı N et al. Enhancement of Ellagic Acid Solubility and Bioaccesibility by Microencapsulation Process and Biotransformation to Urolithins. Journal of food science (2025). PMID 40843976
- Girotra M et al. Induction of mitochondrial recycling reverts age-associated decline of the hematopoietic and immune systems. Nature aging (2023). PMID 37653255
- Broome SC et al. Mitochondria as Nutritional Targets to Maintain Muscle Health and Physical Function During Ageing. Sports medicine (Auckland, N.Z.) (2024). PMID 39060742
- Di Y et al. Urolithin A Exhibits Antidepressant-like Effects by Modulating the AMPK/CREB/BDNF Pathway. Nutrients (2025). PMID 40732919
- Venkatesan A et al. Mitochondrial and microtubule defects in Exfoliation Glaucoma. Free radical biology & medicine (2025). PMID 40180018
- Napier BA et al. Multi-Species Synbiotic Supplementation Enhances Gut Microbial Diversity, Increases Urolithin A and Butyrate Production, and Reduces Inflammation in Healthy Adults: A Randomized, Placebo-Controlled Trial. Nutrients (2025). PMID 40944126
- Ryu D et al. Urolithin A induces mitophagy and prolongs lifespan in C. elegans and increases muscle function in rodents. Nature medicine (2016). PMID 27400265
- Dao T et al. Sarcopenia and Muscle Aging: A Brief Overview. Endocrinology and metabolism (Seoul, Korea) (2020). PMID 33397034
- Ancel S et al. Strengthening muscle for healthy ageing: innovative treatments for sarcopenia. Nature reviews. Drug discovery (2026). PMID 42706321
- Gao Z et al. Urolithin A protects against acetaminophen-induced liver injury in mice via sustained activation of Nrf2. International journal of biological sciences (2022). PMID 35342347
- Kuerec AH et al. Targeting aging with urolithin A in humans: A systematic review. Ageing research reviews (2024). PMID 39002645
- Singh A et al. Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population. European journal of clinical nutrition (2022). PMID 34117375
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.