Supplements · Diets
exogenous ketones improves exercise performance
In plain terms: Do ketone sports supplements boost athletic performance?
Part of: 🧪 exogenous ketones
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)
How the studies fall
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 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 et al 2026 · study_type: RCT | 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 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 et al 2025 · study_type: RCT | 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. |
| Poffe 2019 · J Physiol | RCT | supports | moderate | Ketone-ester post-exercise during 3-wk overload blunted overreaching and enhanced endurance performance vs control. |
| Poffe 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 et al] # corrected 2026-08-17 from PubMed; was [(SR 10 studies) 2020 · (SR) | meta-analysis | mixed | moderate | [FT-verified] Margolis2020 10 studies/16 outcomes 3pos/10null/3neg; I2 83-93%; 109/112 male; no consistent ergogenic effect |
| Evans 2018 · Med Sci Sports Exerc | RCT | tested-null | moderate | Ketone-ester before intermittent running did not enhance physical performance (and reduced gut comfort); no cognitive benefit. |
| Brooks 2022 · Int J Sport Nutr Exerc Metab | meta-analysis | contradicts | high | [FT-verified] Brooks2022 8RCTs n=80 endurance g=0.136 (CI -0.195,0.467) p=.42; TTE&TT null; 77/80 male |
| Crabtree CD et al 2025 · study_type: RCT | 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, et al. 2020 · (MA) | meta-analysis | contradicts | high | [FT-verified] Valenzuela2020 13RCTs overall g=-0.05 (CI -0.30,0.20) p=.68; null endurance/esters/salts |
| Cox 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 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 2020 · J Hum Kinet | RCT | tested-null | moderate | bHB-salt+MCT supplement did not improve 5-km running performance in recreational endurance runners vs placebo. |
| Evans 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 et al 2025 · study_type: observational | 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 et al 2026 · study_type: RCT | RCT | contradicts | moderate | n=18 recreational runners, 31-day randomized single-blind trial of thrice-daily ketone monoester (90 g/day) vs placebo; 5-km time trial performance was NOT altered by KME, though cognitive function improved. |
Disagree, or know a study we missed?
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.