Creatine monohydrate has decades of research behind it and a well-understood mechanism: it replenishes the phosphocreatine energy system in muscle cells, supporting short bursts of high-intensity effort. Urolithin A is a newer arrival to the conversation, with a fundamentally different mechanism: it works upstream of energy production by triggering mitophagy, the cellular process that clears out damaged mitochondria so healthier ones can take their place.
Both compounds have attracted serious clinical interest for muscle health and physical performance, but they address different biological bottlenecks. Understanding what each one actually does, and what the evidence does and does not show, can help you have a more informed conversation with a healthcare provider about whether either belongs in your routine.
Key Takeaways
- Creatine monohydrate replenishes the phosphocreatine energy system and has a large body of evidence for improving high-intensity exercise performance, and a meta-analysis in older females found that adding it to resistance training increased upper-body strength [1][2].
- Urolithin A works by inducing mitophagy, clearing out damaged mitochondria, and has been tested in company-funded randomized trials in middle-aged and older adults that missed their primary endpoints, with gains in muscle endurance and some biomarkers on secondary measures [3][4].
- The two compounds address different biological bottlenecks: creatine is an acute energy-supply intervention; urolithin A is a longer-term mitochondrial quality-control intervention.
- Benefits from creatine can appear within days to a week; urolithin A effects in clinical trials emerged over weeks to months of consistent use.
- No head-to-head or combination trial currently exists: comparisons between the two compounds are mechanistic, not directly tested against each other.
How Creatine Works in Muscle
Creatine is stored in skeletal muscle primarily as phosphocreatine. During short, intense efforts (a heavy lift, a sprint, a rapid jump) phosphocreatine donates a phosphate group to regenerate ATP (adenosine triphosphate), the cell’s primary energy currency, faster than other metabolic pathways can. Supplementing with creatine monohydrate increases the total phosphocreatine pool in muscle, which means more ATP can be regenerated quickly during high-demand activity.
This mechanism is well-characterized and has earned creatine monohydrate one of the most robust safety and efficacy profiles in sports nutrition. A position statement from the International Society of Sports Nutrition concluded that creatine monohydrate is the most effective ergogenic nutritional supplement available for increasing high-intensity exercise capacity and lean body mass during training [1]. The effect is most pronounced for efforts lasting roughly 10 to 30 seconds, with benefits tapering off for longer-duration aerobic work.
How Urolithin A Works: Mitophagy and Mitochondrial Renewal
Urolithin A works through a different pathway entirely. Mitochondria, the organelles responsible for generating most of the ATP your cells use, accumulate damage over time. When that damaged mitochondrial population grows, energy production becomes less efficient and cellular stress increases. Mitophagy is the quality-control process that selectively removes dysfunctional mitochondria, making room for healthier replacements.
Research note: In a trial of older adults, creatine taken after resistance training raised lean tissue mass by 3.0 kg versus 0.5 kg for placebo [17].
Urolithin A is a postbiotic compound produced when gut bacteria metabolize ellagitannins found in foods like pomegranates, walnuts, and certain berries. Research in model organisms showed it directly induces mitophagy, extending lifespan in C. elegans and improving muscle function in rodents [5]. In human cells and clinical studies, the working hypothesis is that by stimulating mitophagy, urolithin A helps restore a higher-quality mitochondrial pool, particularly relevant in aging muscle where mitochondrial dysfunction accumulates [6].
It is worth noting that people differ widely in how much urolithin A they produce from food because gut microbiome composition varies, and some produce little or none. Oral supplementation bypasses this conversion step, which is why clinical trials have used a direct supplement form.
Clinical Evidence for Urolithin A
Human trial evidence for urolithin A has grown notably since 2022. A randomized controlled trial in middle-aged adults missed its pre-specified primary endpoint (peak power on a cycling test); hamstring strength, a secondary endpoint, rose in the treated groups while the placebo group declined, and the trial was sponsored by the maker of Mitopure [3]. A separate randomized clinical trial published in JAMA Network Open in 66 older adults reported better muscle endurance as a secondary endpoint, with very large standard deviations, while walk distance and maximal muscle ATP production showed no significant improvement versus placebo; it was funded by Amazentis [4].
Additional preclinical evidence comes from a muscular dystrophy model, where urolithin A is reported to have improved muscle function by activating mitophagy pathways; this is not a patient trial [7]. A 2024 systematic review examining urolithin A studies in humans of five human studies (250 healthy people) found a dose-dependent anti-inflammatory effect and some upregulated mitochondrial genes, but no effect on maximal mitochondrial ATP production or on physical function, and called for further research [8].
An important nuance: the two main urolithin A trials missed their primary endpoints (peak power on a cycling test, and walk distance with maximal muscle ATP production), and the endurance and strength gains came from secondary endpoints [3][4]the domains where creatine is most established.
Clinical Evidence for Creatine
Creatine’s clinical record is substantially longer. A meta-analysis in older females, a population where both muscle mass and strength are clinically important, found that adding creatine supplementation to resistance training significantly increased upper-body strength, with no significant effect on lower-body strength or measures of muscle mass overall [2]. An umbrella review of nutritional interventions for muscle in older people included creatine among the interventions with meaningful supporting evidence [9].
There is also growing interest in creatine beyond athletic performance. Research has explored its relevance across different populations including older women [10], and a 2024 review examined the evidence for creatine’s effects on muscle, bone, and brain in older adults, noting that while muscle evidence is strong, some other claimed benefits require more research [11]. One study examining creatine and resistance training in older adults also found favorable effects on oxidative stress markers and quality of life [12], suggesting the benefits may extend beyond the phosphocreatine energy pathway alone.
Evidence on muscle size is more mixed. A meta-analysis of imaging-based studies found creatine plus training gave only a very small muscle-size gain over training alone (pooled estimate 0.11, interval crossing zero), while a meta-analysis of 357 older adults found creatine added to resistance training raised fat-free mass more than training alone and improved the 30-second chair stand test [14][15].
Key Differences: Mechanism, Population, and Purpose
The most fundamental difference between these two compounds is the biological problem each one addresses. Creatine tops up an acute energy reserve: it helps muscle cells perform harder, faster, and recover between sets. The effect is relatively immediate: phosphocreatine stores saturate within a few days to a week of loading, and performance benefits can be measurable soon after. Urolithin A, by contrast, works on cellular maintenance. It takes weeks to months of consistent supplementation before mitophagy-related changes in mitochondrial health markers appear in clinical studies [3][4].
Creatine has the stronger muscle record in older adults; urolithin A's gains came from secondary measures
88 adults, company-funded
The main goal, peak power on a cycling test, did not change significantly. Hamstring strength, a secondary measure, rose in the treated groups.
66 older adults, company-funded
Walk distance and maximal muscle ATP production did not improve significantly versus placebo. Muscle endurance, a secondary measure, did, with very large spread.
357 older adults, pooled trials
Added to resistance training, creatine raised fat-free mass more than training alone and improved the 30-second chair stand test (P = 0.03).
Imaging studies
A meta-analysis found only a very small muscle-size gain over training alone (pooled estimate 0.11, interval crossing zero).
Creatine has more and better muscle evidence in older adults, while urolithin A's human results are early and mixed.
Different trials, doses and outcomes, so read the cards side by side rather than as a ranking. Source: Singh et al., Cell Reports Medicine 2022; Liu et al., JAMA Network Open 2022; Devries et al., Medicine and Science in Sports and Exercise 2014; Burke et al., Nutrients 2023.
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Their target populations also differ in emphasis. Creatine has the most robust evidence in the context of resistance training: people actively loading their muscles benefit most from a larger phosphocreatine pool. Urolithin A research has focused heavily on aging-related mitochondrial decline, with trials enrolling middle-aged and older adults rather than trained athletes. This does not mean younger people cannot benefit, but it suggests the compound may be most relevant where mitochondrial dysfunction is already a factor.
A practical way to think about it: creatine is a fuel-supply intervention and urolithin A is a fuel-system maintenance intervention. One fills the tank faster; the other helps keep the engine running cleanly.
Can They Work Together?
There is no clinical trial as of this writing that has directly tested urolithin A and creatine in combination, so any claim about a synergistic effect would go beyond the current evidence. What can be said is that the mechanisms do not overlap in any obvious way that would create interference: creatine operates via the phosphagen system and urolithin A via mitophagy and mitochondrial quality control. They address separate aspects of muscle energy metabolism.
From a theoretical standpoint, creatine could support higher training intensity in the short term while urolithin A supports the mitochondrial infrastructure that sustains energy production over time. However, this remains speculative. Anyone considering combining supplements should discuss it with a healthcare provider, particularly if they have underlying health conditions or take medications.
🛒 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 evidence for both compounds continues to evolve, and most urolithin A trials to date have been relatively short-term and conducted in specific age groups: results may not generalize to all populations. Neither supplement is a substitute for medical treatment or a replacement for a balanced diet and regular physical activity; anyone with a health condition, taking medications, or pregnant should speak with a qualified healthcare provider before starting either supplement.
Frequently Asked Questions
Does urolithin A actually increase muscle strength like creatine does?
A company-funded randomized trial in middle-aged adults missed its primary endpoint (peak power on a cycling test), though hamstring strength, a secondary endpoint, rose in the treated groups while the placebo group declined [3], and a JAMA Network Open trial in older adults reported better muscle endurance as a secondary endpoint [4]. However, the magnitude and mechanism of strength gains differ from creatine: urolithin A’s benefits appear linked to mitochondrial health rather than the phosphocreatine energy reserve that creatine targets.
How quickly does each supplement take effect?
Creatine loading saturates muscle phosphocreatine stores within days, and performance benefits are often measurable soon after [1]. Urolithin A clinical trials have typically run for four weeks or longer before changes in some mitochondrial health markers appeared, and the performance results were mostly on secondary endpoints [13][3][4], reflecting the time needed for mitophagy-driven mitochondrial renewal.
An 8-week trial in 20 resistance-trained men gave 1 g a day of urolithin A or placebo; maximum voluntary contraction and repetitions to failure improved, but 1RM bench press and squat gains did not reach significance, and the authors state the study did not show improved muscle strength [16].
Is creatine safe for long-term use?
Long-term use of creatine monohydrate at recommended doses has a well-established safety profile in healthy individuals, and the International Society of Sports Nutrition has stated it is one of the safest and most well-studied nutritional supplements available [1]. People with kidney disease or other conditions should consult a physician before use.
Who is urolithin A most likely to benefit?
Clinical trial evidence to date has primarily enrolled middle-aged and older adults, populations where mitochondrial dysfunction in muscle is more prevalent [3][4][8]. A 2024 systematic review noted urolithin A shows promise for addressing aging-related decline, though the authors emphasized the need for larger and longer trials [8].
Does everyone absorb urolithin A the same way from food?
No. Urolithin A is produced by gut bacteria from ellagitannins in foods like pomegranates and walnuts, and the ability to make meaningful amounts depends heavily on individual gut microbiome composition [6]. A substantial portion of people produce little or no urolithin A from dietary sources, which is why clinical trials use a directly supplemented form.
Can creatine benefit older adults, not just athletes?
Yes. A meta-analysis found creatine supplementation combined with resistance training increased upper-body strength in older females, with no significant effect on lower-body strength or measures of muscle mass overall [2], and a review of nutritional interventions for muscle in older people identified creatine as having meaningful supporting evidence [9]. Research has also examined creatine’s potential benefits for muscle, bone, and cognitive health in aging populations, though the evidence is stronger for muscle outcomes than others [11].
References
- Kreider RB et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition (2017). PMID 28615996
- Dos Santos EEP et al. Efficacy of Creatine Supplementation Combined with Resistance Training on Muscle Strength and Muscle Mass in Older Females: A Systematic Review and Meta-Analysis. Nutrients (2021). PMID 34836013
- Singh A et al. Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults. Cell reports. Medicine (2022). PMID 35584623
- 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
- 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
- D'Amico D et al. Impact of the Natural Compound Urolithin A on Health, Disease, and Aging. Trends in molecular medicine (2021). PMID 34030963
- Luan P et al. Urolithin A improves muscle function by inducing mitophagy in muscular dystrophy. Science translational medicine (2021). PMID 33827972
- Kuerec AH et al. Targeting aging with urolithin A in humans: A systematic review. Ageing research reviews (2024). PMID 39002645
- Gielen E et al. Nutritional interventions to improve muscle mass, muscle strength, and physical performance in older people: an umbrella review of systematic reviews and meta-analyses. Nutrition reviews (2021). PMID 32483625
- Smith-Ryan AE et al. Creatine Supplementation in Women's Health: A Lifespan Perspective. Nutrients (2021). PMID 33800439
- Candow DG et al. Effects of Creatine Monohydrate Supplementation on Muscle, Bone and Brain- Hope or Hype for Older Adults?. Current osteoporosis reports (2024). PMID 39509039
- Amiri E et al. The role of resistance training and creatine supplementation on oxidative stress, antioxidant defense, muscle strength, and quality of life in older adults. Frontiers in public health (2023). PMID 37206869
- Andreux PA et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nature metabolism (2019). PMID 32694802
- Burke R et al. The Effects of Creatine Supplementation Combined with Resistance Training on Regional Measures of Muscle Hypertrophy: A Systematic Review with Meta-Analysis. Nutrients (2023). PMID 37432300
- Devries MC et al. Creatine supplementation during resistance training in older adults-a meta-analysis. Medicine and science in sports and exercise (2014). PMID 24576864
- 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
- Candow DG et al. Strategic creatine supplementation and resistance training in healthy older adults. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme (2015). PMID 25993883
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.