Supplements · Diets
exogenous ketones improves exercise performance
In plain terms: Do ketone sports supplements boost athletic performance?
Leans against Supplements 🔬 Includes disconfirming
Part of: 🧪 exogenous ketones
RefutedContestedStrong support
consensus score -0.54
Probably not — pooled trials show no net benefit, and the famous positive study was industry-run and failed to replicate.
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
2 support 9 contradict 3 tested null 1 mixed · 15 sources, 10 independent groups
What the evidence shows
The marketed 'ketones boost athletic performance' claim is NET NULL across meta-analyses; the famous positive Oxford trial is from the ester's patent-holders and failed independent replication, and ketone ester even causes a mild acidosis that offsets benefit.
The evidence (17)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Dearlove DJ, Soto Mota A, Hauton D, Pinnick K, Evans R, Miller J, Fischer R, Mccullagh JSO, Hodson L, Clarke K, Cox PJ 2022 · Physiol Rep | RCT | tested-null | moderate | Exogenously-induced hyperketonemia (ketone drinks) did not improve exercise capacity in trained cyclists over 6-day race simulation. |
| Martyn HJ, Cameron NE, Edmondson JA, Phelan MM, Gonzalez JT, Shepherd SO, Pugh JN, Owens DJ, Morton JP 2026 · Journal of applied physiology (Bethesda, Md. : 1985) | RCT | contradicts | high | n=8 trained male cyclists, randomized crossover; exercise capacity to exhaustion at 150% LT was NOT different between CHO (349s) and CHO+ketone monoester (319s), both > placebo. KME also lowered exogenous CHO oxidation and oxidation efficie |
| Leckey JJ, Ross ML, Quod M, Hawley JA, Burke LM 2017 · Front Physiol | RCT | contradicts | moderate | Ketone diester ingestion impaired ~31-km cycling time-trial performance in professional cyclists (GI distress, slower times). |
| Tominec D, Stalmans M, Narang BJ, Millet GP, Poffé C, Debevec T 2025 · Medicine and science in sports and exercise | RCT | contradicts | high | n=33 healthy adults (16 KE, 17 placebo), randomized crossover cycling to exhaustion at high altitude; ketone monoester elevated blood ketones (~2.1mM) but altitude-induced reductions in peak power output were comparable between groups (P=0. |
| Poffé C, Ramaekers M, Van Thienen R, Hespel P 2019 · J Physiol | RCT | supports | moderate | Ketone-ester post-exercise during 3-wk overload blunted overreaching and enhanced endurance performance vs control. |
| Poffé C, Wyns F, Ramaekers M, Hespel P 2021 · Med Sci Sports Exerc | RCT | contradicts | high | Ketone ester impaired 30-min cycling time-trial performance, independent of bicarbonate co-ingestion (acidosis-mediated decrement). |
| Margolis LM, O'Fallon KS 2020 · (SR) | meta-analysis | mixed | moderate | Margolis2020 10 studies/16 outcomes 3pos/10null/3neg; I2 83-93%; 109/112 male; no consistent ergogenic effect |
| Evans M, Egan B 2018 · Med Sci Sports Exerc | RCT | contradicts | moderate | Evans & Egan 2018 double-blind crossover, 11 male team-sport athletes, carbohydrate drink with vs without 750 mg/kg ketone ester: 'Run time to exhaustion was not different (P = 0.126, d = 0.45) between PLA (mean = 268 s ...) and KE (mean = 229 s ...)'; 15-m sprint times did not differ. Null (numerically worse) on a directional claim = contradicts. Small n. Separate finding: attenuated post-exercise executive-function decline (P = 0.017). |
| Brooks E, Lamothe G, Nagpal TS, Imbeault P, Adamo K, Kara J, Doucet É 2022 · Int J Sport Nutr Exerc Metab | meta-analysis | contradicts | high | Brooks2022 8RCTs n=80 endurance g=0.136 (CI -0.195,0.467) p=.42; TTE&TT null; 77/80 male |
| Crabtree CD, Stoner J, Buga A, Robinson B, Decker D, Chebbi A, El-Shazly X, Murphy E, Jordan A, Bedell T, Kackley ML, McClure T, Han Y, Simonetti OP, Volek JS 2025 · Physiological reports | RCT | contradicts | moderate | n=12 recreationally active adults, double-blind crossover; VO2max was LOWER after ketone ester (BO-BD) ingestion vs placebo (P<0.001), though total time to exhaustion was similar; no differences in exercise lactate, RER, or RPE. |
| Valenzuela PL, Morales JS, Castillo-García A, Lucia A 2020 · (MA) | meta-analysis | contradicts | high | Valenzuela2020 13RCTs overall g=-0.05 (CI -0.30,0.20) p=.68; null endurance/esters/salts |
| Cox PJ, Kirk T, Ashmore T, Willerton K, Evans R, Smith A, Murray AJ, Stubbs B, West J, McLure SW, King MT, Dodd MS, Holloway C, Neubauer S, Drawer S, Veech RL, Griffin JL, Clarke K 2016 · Cell Metab | RCT | supports | high | Ketone-ester drink in 39 elite athletes shifted fuel use (less glycolysis), improved cycling distance ~2% vs CHO - the flagship positive study. |
| Tominec D, Stalmans M, Narang BJ, Millet GP, Poffé C, Debevec T 2026 · J Appl Physiol | RCT | tested-null | moderate | Exogenous ketosis did not alter oxygenation, O2 uptake kinetics or whole-body efficiency during submaximal exercise at altitude. |
| Prins PJ, Koutnik AP, D'Agostino DP, Rogers CQ, Seibert JF, Breckenridge JA, Jackson DS, Ryan EJ, Buxton JD, Ault DL 2020 · J Hum Kinet | RCT | tested-null | moderate | Double-blind randomised crossover, n=10 recreational male runners, 300 mg/kg beta-HB salt + MCT vs flavour-matched placebo 60 min before a treadmill 5 km time trial: 1430.0 +/- 187.7 s vs 1488.3 +/- 243.8 s, mean 58.3 s (4.06%) faster, 95% CI -130.12 to 13.52, p=0.100, ES 0.27; 8 of 10 ran faster. No other physiological, metabolic or perceptual differences. Underpowered estimate compatible with both no effect and a large benefit, point estimate favouring the supplement - neither a clean null nor a finding. Co-author D'Agostino holds ketone patents and owns Ketone Technologies LLC. |
| Evans M, McClure TS, Koutnik AP, Egan B 2022 · Sports Med | observational | mixed | moderate | Narrative/critical review: some studies suggest benefit to recovery/overreaching but many fail to show acute performance gains; net unproven. |
| Siri M, Hosseini EM, Mazhari SA, Jalali P, Soltaninejad K, Raji MA, Yazdekhasti N, Naseri E, Mohammadi A, Maleki MH 2025 · Nutrition & metabolism | observational | mixed | low | Narrative review of ketogenic supplements (exogenous ketones, MCT oil, ketone esters) in exercise nutrition, summarizing potential mechanisms for endurance benefit alongside known drawbacks (glycogen depletion, GI distress, electrolyte imba |
| Prins PJ, Buga A, Storoschuk K, Buxton JD, Jenkins AK, Eklund CS, Dacey VC, Belitz SE, Sullivan RJ, Gerhart HD, D'Agostino DP, Volek JS, Koutnik AP 2026 · J Am Nutr Assoc | RCT | contradicts | moderate | Single-blind RCT, 18 recreational runners randomised 9 KME vs 9 isocaloric flavour-matched placebo, 30 g/dose thrice daily (90 g/day) for 31 days: 31-day KME did not alter 5KTT performance. The null is a 9-vs-9 between-arm comparison and no power calculation is visible in the abstract, so it is a weak null rather than a demonstrated absence of effect. The cognitive gains (Stroop, switching) and the post-washout preservation of absolute VO2 are off-object: the authors state they occurred without accompanying improvements in running performance. Abstract-grade read. |
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