Coenzyme Q10 for Athletes: What the Evidence Says
Coenzyme Q10 sits at the heart of the mitochondrial energy chain, so it is no surprise that it attracts the attention of endurance athletes and gym-goers alike. Supplement labels promise more energy, faster recovery and protection against oxidative stress. Our editorial team examined the clinical studies to separate the solid findings from the marketing.
What CoQ10 does in muscle
Coenzyme Q10, or ubiquinone, is a fat-soluble compound found in the inner membrane of mitochondria. It shuttles electrons between complexes of the respiratory chain, a step essential for producing ATP, the cell's energy currency. In its reduced form, ubiquinol, it also acts as an antioxidant within cell membranes and lipoproteins.
The body makes its own CoQ10 through the same mevalonate pathway that produces cholesterol. Tissues with high energy demands, such as the heart, liver, kidneys and skeletal muscle, contain the highest concentrations. Diet contributes a relatively small amount, mainly from meat, oily fish and organ meats.
Endogenous production tends to decline with age, and statin drugs, which block the mevalonate pathway, also reduce circulating CoQ10. These observations underpin much of the clinical interest in supplementation, although lower blood levels do not automatically mean that muscle function is impaired.
For a young, well-nourished athlete, there is no established CoQ10 deficiency to correct. The question is therefore whether adding more than the body makes provides any extra benefit.
Performance: endurance and power
Results from performance trials are mixed. Cooke and colleagues studied both trained and untrained people taking CoQ10 for 14 days and reported higher plasma and muscle CoQ10 levels, with some improvements in time to exhaustion, although differences between groups were modest and not consistent across all measures.
Other small trials found no benefit on maximal oxygen uptake, time-trial performance or anaerobic power. A systematic review by Sarmiento and colleagues concluded that the evidence for improved physical performance in healthy people is inconclusive, with heterogeneity in doses, forms and study populations.
Part of the problem is that well-trained muscle already has a large mitochondrial capacity. If CoQ10 is not a limiting factor in energy production, adding more will not increase output, in the same way that an extra fuel line does not make an engine more powerful if the fuel supply was never restricted.
The IOC consensus statement on dietary supplements, published in 2018, does not list CoQ10 among supplements with good evidence for performance enhancement, placing it in a group where benefits remain unproven.
Muscle damage, oxidative stress and recovery
The more promising signals relate to recovery. Kon and colleagues studied Japanese kendo athletes during an intensive training camp. Those taking CoQ10 showed smaller rises in creatine kinase and myoglobin, two blood markers of muscle damage, compared with placebo.
Several studies have also reported lower markers of lipid peroxidation after exercise in people taking CoQ10. However, reduced markers do not necessarily mean better adaptation. There is ongoing debate in sports science about whether blunting oxidative stress with high-dose antioxidants might interfere with some training adaptations, as has been shown for vitamins C and E in certain studies.
The evidence for CoQ10 specifically in this regard is limited, but athletes who prioritise long-term adaptation might reasonably reserve antioxidant supplements for periods of very high load, such as training camps or tournaments, rather than using them year-round.
Subjective outcomes such as perceived fatigue have improved in some trials, though these are especially vulnerable to placebo effects. Overall, the recovery picture is interesting but not yet strong enough to make CoQ10 a priority supplement.
Forms, absorption and amounts used in research
CoQ10 is a large, highly fat-soluble molecule and is poorly absorbed. Bhagavan and Chopra describe absorption as slow and limited, improved when the supplement is taken with a meal containing fat and by formulations using oil suspensions or solubilisation technologies.
| Form | Description | Practical notes |
|---|---|---|
| Ubiquinone powder | Oxidised form in tablets or hard capsules | Cheapest; lowest absorption without fat |
| Ubiquinone in oil (softgel) | Dissolved in vegetable oil | Better absorption than dry powder |
| Ubiquinol | Reduced form | Often marketed as superior; data in young adults limited |
| Solubilised forms | Water-dispersible formulations | Higher blood levels in some comparisons |
Studies in athletes have mostly used between 100 and 300 mg per day, often divided into two doses with meals, for periods of two weeks to several months. Blood levels rise over the first few weeks, so short courses of a few days are unlikely to show any effect.
When choosing a product, look for the amount of CoQ10 per capsule, the form used, and evidence of independent testing. Claims about "superior bioavailability" are common, but differences between brands are not always meaningful in practice.
Safety, interactions and who may benefit most
CoQ10 has a reassuring safety record. A risk assessment by Hathcock and Shao proposed an observed safe level of 1200 mg per day, well above amounts used in sports studies. The most commonly reported side effects are mild digestive complaints and occasionally insomnia when taken late in the evening.
The main interaction of concern is with warfarin. CoQ10 is structurally similar to vitamin K and may reduce the anticoagulant effect, so anyone taking warfarin must discuss supplementation with their doctor or anticoagulation clinic. People on blood pressure or diabetes medication should also seek advice.
- May be worth considering: older masters athletes, people taking statins who experience muscle symptoms (with medical supervision), and those in very demanding training blocks.
- Unlikely to benefit: young, healthy athletes seeking a direct performance boost.
- Medical use: CoQ10 has been studied in heart failure; the Q-SYMBIO trial reported favourable outcomes, but this is a clinical context requiring cardiology care.
CoQ10 is not on the WADA Prohibited List. As with all supplements, tested athletes should use batch-tested products to minimise contamination risk.
Conclusions of the editorial team
CoQ10 is essential for energy production, but supplements do not reliably improve endurance or strength in healthy athletes. The evidence for reduced muscle damage markers during intense training is more encouraging but still limited.
If you decide to try it, choose an oil-based or solubilised product, take it with a meal and allow several weeks before judging results. Check interactions, especially with warfarin.
For most athletes, CoQ10 is a "nice to have" rather than a priority. Creatine, caffeine and an adequate diet offer far stronger evidence.
You may also want to read our pieces on statins and exercise, antioxidants and training adaptation, and nitrate supplements for endurance sport.
References
- Sarmiento A, Diaz-Castro J, Pulido-Moran M, et al. Coenzyme Q10 supplementation and exercise in healthy humans: a systematic review. Curr Drug Metab. 2016;17(4):345–358.
- Cooke M, Iosia M, Buford T, et al. Effects of acute and 14-day coenzyme Q10 supplementation on exercise performance in both trained and untrained individuals. J Int Soc Sports Nutr. 2008;5:8.
- Kon M, Tanabe K, Akimoto T, et al. Reducing exercise-induced muscular injury in kendo athletes with supplementation of coenzyme Q10. Br J Nutr. 2008;100(4):903–909.
- Bhagavan HN, Chopra RK. Coenzyme Q10: absorption, tissue uptake, metabolism and pharmacokinetics. Free Radic Res. 2006;40(5):445–453.
- Hathcock JN, Shao A. Risk assessment for coenzyme Q10 (Ubiquinone). Regul Toxicol Pharmacol. 2006;45(3):282–288.
- Mortensen SA, Rosenfeldt F, Kumar A, et al. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial. JACC Heart Fail. 2014;2(6):641–649.
- Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.
