Ketones for runners: what's being used and what the research says
We report what runners are using and what the research says. We don't recommend taking any supplement. Talk to your GP or a registered sports dietitian before trying one.
Quick answer
Research suggests they don't. Two meta-analyses of randomised trials found no effect on endurance performance[1][2], and a review of studies in endurance runners found no benefit[3]. In professional cyclists, a ketone drink made a time trial 2% slower, and every rider who finished reported stomach upset[4].
- Research
- Weak (proposed)Meta-analyses found no performance benefit, and running trials from 5 km to 10 km found none. Stomach upset is common.
- Proposed by our editor; not yet confirmed by an expert reviewer.
- WADA status
- Permitted
- Distances in the research
- 800 m–5K: studied10K–half: limited researchMarathon: not studiedUltra: limited research
What are ketone supplements?
Ketones are fuels the liver makes when energy or carbohydrate is short, such as during fasting or a ketogenic diet. Ketone supplements raise blood ketones without cutting carbohydrate[5].
They come as ketone esters, ketone salts bound to sodium, potassium or calcium, and related compounds. The Australian Institute of Sport lists them in Group B, for use in research or clinical monitoring[5].
Also called: ketone esters, ketone salts, ketone drinks, exogenous ketones, beta-hydroxybutyrate (BHB).
Why are ketone supplements getting attention?
Ketone supplements have become popular with endurance runners on the promise of delaying fatigue[3].
Interest grew after an early cycling study found about 2% more distance in a 30-minute time trial, a benefit most later studies haven't supported[6][7]. Use in professional cycling is reportedly still widespread[6].
How do ketone supplements work?
The idea is an extra fuel for muscles and the brain. But recent studies suggest ketones supply only about 2 to 5% of the fuel used during exercise[5].
Ketone drinks also make the blood more acidic, which the AIS says may work against performance in some sports[5].
Do ketone supplements improve running performance?
No. Two meta-analyses of randomised trials found no effect on endurance performance, one covering ketone esters and salts[1], the other esters and related precursors[2]. A review of 12 studies in endurance runners found no benefit from ketone supplements or ketogenic diets[3].
800 m to 5K (Studied)
Over 5 km, trials found no difference with a ketone precursor taken with carbohydrate[8] or after 31 days of a ketone ester[9]. In an 800 m trial, 10 days of ketone salts didn't change a first run, though the ketone group's average over two runs got faster[10].
10K to half marathon (Limited research)
In 8 trained runners, a ketone ester with carbohydrate made no difference to a 10 km time trial[11]. Elite race walkers who took a ketone ester after a 5-day ketogenic diet were about 6% slower over 10,000 m[12].
Marathon (Not studied)
We found no controlled trials of ketone supplements in marathons. The largest meta-analysis covered events of up to about 50 minutes[1].
Ultra (Limited research)
A review of runner studies describes a randomised trial in 18 male ultra runners, over distances up to 100 km, in which a ketone ester made no difference to performance[3]. The ISSN says evidence for ketones in ultra-marathons is lacking[7].
The key studies, in order
- 2017Trial10 professional cyclists: a ketone diester made a 31 km time trial about 2% slower. All reported gut discomfort, and an eleventh rider couldn't start because of vomiting. [4]
- 2018ConsensusSupplements can contain prohibited substances as undeclared ingredients or contaminants, and athletes are responsible for anything found in their sample. [15]
- 2019Trial8 endurance-trained runners: a ketone ester with carbohydrate made no difference to a 10 km time trial after an hour of running, compared with carbohydrate alone. [11]
- 2019Trial11 male runners: a ketone precursor with carbohydrate made no difference to a 5 km time trial after 60 minutes of running, compared with carbohydrate alone. [8]
- 2019TrialThree studies of ketone drinks: gut symptoms were mostly mild and short-lived, and high-dose ketone salts caused the most. Authors linked to a ketone drink maker. [13]
- 2019ConsensusEvidence for ketogenic diets or ketone esters improving ultra-marathon performance is lacking; performance benefits of ketone esters have been repeatedly refuted. [7]
- 2020Meta-analysis13 randomised trials: no effect on exercise performance overall, on time trials, or for ketone esters or salts separately, in events of up to about 50 minutes. [1]
- 2021Non-randomised trial18 elite race walkers: after a 5-day ketogenic diet plus a ketone ester, all nine in that group raced 10,000 m about 6% slower. Walkers chose their diet group. [12]
- 2022Meta-analysis8 trials, 80 people (77 men): no effect on endurance performance. 6 of 7 studies that checked found more gut symptoms with ketones than with a control drink. [2]
- 2022Expert reviewAn early cycling study found about 2% more distance in a 30-minute time trial, but little support has followed despite many studies. Use in professional cycling is reportedly widespread. [6]
- 2022Trial32 endurance-trained adults, 10 days of ketone salts: a first 800 m run didn't change; the ketone group's average over two runs got faster, the placebo group's didn't. [10]
- 2025Systematic review12 studies, 132 endurance runners (131 men): none found that ketone supplements or ketogenic diets improved aerobic performance, including a 100 km ultra trial. [3]
- 2026Trial18 recreational runners: 30 g of a ketone ester three times a day for 31 days didn't change 5 km time-trial performance. [9]
What the research can't tell us yet
Almost all participants were men: 131 of 132 runners in the runner review[3], and 77 of 80 people in one meta-analysis[2].
The trials were small, with 8 to 12 people each in one meta-analysis, and many used cycling rather than running[2].
In the race-walking study, walkers chose their own diet group, and the effect of the ketone ester couldn't be separated from the ketogenic diet[12].
How are ketone supplements used in studies?
Studies in athletes used about 350 to 1,000 mg per kg of body mass (roughly 25 to 75 g), most often taken before, and sometimes during, endurance exercise[5].
Running trials used, for example, 573 mg per kg of a ketone ester with carbohydrate around a 10 km time trial[11], or 30 g of a ketone ester three times a day for 31 days[9].
| What studies used | When | Ref. |
|---|---|---|
| About 350 to 1,000 mg per kg of body mass (25 to 75 g) | Most often before, and sometimes during, endurance exercise | [5] |
| 573 mg per kg of a ketone ester, with carbohydrate | Before and during an hour's run and a 10 km time trial | [11] |
| 30 g of a ketone ester, three times a day | 31 days, in recreational runners | [9] |
What are the side effects, and who should be careful?
Stomach upset is the main side effect: in one meta-analysis, 6 of 7 studies that checked found more gut symptoms with ketones than with a control drink[2]. All 10 professional cyclists who finished one trial reported gut discomfort, and one rider couldn't start because of vomiting[4].
Ketone salts carry a high salt load and are linked to severe gut side effects[5]. A study by researchers linked to a ketone drink maker found symptoms were usually mild and short-lived[13].
Be careful if
- You have a sensitive stomach: gut symptoms were more common with ketones in 6 of 7 studies that checked[2].
- You're planning to use them before a race: ketone drinks make the blood more acidic, which the AIS says may work against performance in some sports[5].
- You're also cutting carbohydrate: elite race walkers on a 5-day ketogenic diet plus a ketone ester were about 6% slower over 10,000 m[12].
Are ketone supplements allowed in competition?
The AIS says ketone esters are not on the World Anti-Doping Agency's Prohibited List[5]. WADA says its list is not exhaustive, so a substance not being named doesn't prove it is allowed[14].
Some sports bodies, such as the Movement for a Credible Cycling (MPCC), have advised members to avoid ketone supplements[5], and any supplement product can be contaminated with prohibited substances[15].
Independent quality-assurance schemes, often called batch testing, check supplement products for prohibited substances[15]. WADA says using a product from one of these schemes can reduce, but not eliminate, the risk of an anti-doping violation[14], and the IOC says no product can be guaranteed entirely safe[15].
Myth or evidence?
5 things runners hear about ketone supplements. Pick an answer to see what the research says.
1.Ketone drinks improve endurance performance.
2.During a run, ketones become a major fuel.
Show the answer
Myth. The AIS says recent studies suggest ketones supply only about 2 to 5% of the fuel used during exercise[5].
3.Ketone supplements can upset your stomach.
Show the answer
Evidence. Gut symptoms were more common with ketones in 6 of 7 studies that checked[2].
4.Ketone salts work as well as ketone esters.
Show the answer
Myth. The AIS says salts raise the form of ketone the body uses less than esters do[5].
5.Ketones are banned by WADA.
Show the answer
Myth. The AIS says ketone esters are not on the WADA Prohibited List[5].
Have you tried ketone supplements?
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Frequently asked questions
- Do ketone drinks make you run faster?
- Research suggests not: two meta-analyses of randomised trials found no effect on endurance performance[1][2], and trials over 5 km and 10 km found no difference[8][11].
- What's the difference between ketone esters and ketone salts?
- The AIS describes esters as salt-free and generally well tolerated. Salts carry a high salt load, raise the form of ketone the body uses less, and are linked to severe gut side effects[5].
- Are ketone supplements banned in sport?
- The AIS says ketone esters aren't on the WADA Prohibited List[5], but WADA says its list isn't exhaustive[14], and some sports bodies, such as a professional cycling association, have advised members to avoid them[5].
- Is taking ketones the same as a ketogenic diet?
- No. Supplements raise blood ketones without cutting carbohydrate, while a ketogenic diet does it by restricting carbohydrate[5]. A review in endurance runners found no performance benefit from either[3].
- Do ketone drinks upset the stomach?
- Often. In one meta-analysis, 6 of 7 studies that checked found more gut symptoms with ketones[2], and all 10 professional cyclists who finished one trial reported gut discomfort[4].
- Do ketones help recovery?
- The AIS says effects on refuelling after exercise are conflicting, and other recovery findings need more research in athletes[5].
References
- [1]
Valenzuela PL, Morales JS, Castillo-García A, Lucia A Acute ketone supplementation and exercise performance: a systematic review and meta-analysis of randomized controlled trials. International Journal of Sports Physiology and Performance, 2020.
Meta-analysis13 randomised trials: no effect on exercise performance overall, on time trials, or for ketone esters or salts separately, in events of up to about 50 minutes.
doi.org/10.1123/ijspp.2019-0918 - [2]
Brooks E, Lamothe G, Nagpal TS, et al. Acute ingestion of ketone monoesters and precursors do not enhance endurance exercise performance: a systematic review and meta-analysis. International Journal of Sport Nutrition and Exercise Metabolism, 2022.
Meta-analysis8 trials, 80 people (77 men): no effect on endurance performance. 6 of 7 studies that checked found more gut symptoms with ketones than with a control drink.
doi.org/10.1123/ijsnem.2021-0280 - [3]
Sun K, Choi YT, Yu CCW, et al. The effects of ketogenic diets and ketone supplements on the aerobic performance of endurance runners: a systematic review. Sports Health, 2025.
Systematic review12 studies, 132 endurance runners (131 men): none found that ketone supplements or ketogenic diets improved aerobic performance, including a 100 km ultra trial.
doi.org/10.1177/19417381241271547 - [4]
Leckey JJ, Ross ML, Quod M, et al. Ketone diester ingestion impairs time-trial performance in professional cyclists. Frontiers in Physiology, 2017.
Randomised controlled trial10 professional cyclists: a ketone diester made a 31 km time trial about 2% slower. All reported gut discomfort, and an eleventh rider couldn't start because of vomiting.
doi.org/10.3389/fphys.2017.00806 - [5]
Australian Institute of Sport AIS Sports Supplement Framework: Group B and linked fact sheets. Australian Sports Commission, 2026.
Consensus statementLists ketone supplements in Group B, for research or clinical monitoring. No scientific consensus on a performance benefit; recent studies suggest ketones supply only about 2-5% of fuel during exercise.
www.ausport.gov.au/ais/nutrition/supplements/group_b - [6]
Evans M, McClure TS, Koutnik AP, Egan B Exogenous ketone supplements in athletic contexts: past, present, and future. Sports Medicine, 2022.
Expert reviewAn early cycling study found about 2% more distance in a 30-minute time trial, but little support has followed despite many studies. Use in professional cycling is reportedly widespread.
doi.org/10.1007/s40279-022-01756-2 - [7]
Tiller NB, Roberts JD, Beasley L, et al. International Society of Sports Nutrition position stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition, 2019.
Consensus statementEvidence for ketogenic diets or ketone esters improving ultra-marathon performance is lacking; performance benefits of ketone esters have been repeatedly refuted.
doi.org/10.1186/s12970-019-0312-9 - [8]
Scott BE, Laursen PB, James LJ, et al. The effect of 1,3-butanediol and carbohydrate supplementation on running performance. Journal of Science and Medicine in Sport, 2019.
Randomised controlled trial11 male runners: a ketone precursor with carbohydrate made no difference to a 5 km time trial after 60 minutes of running, compared with carbohydrate alone.
doi.org/10.1016/j.jsams.2018.11.027 - [9]
Prins PJ, Buga A, Storoschuk K, et al. The effects of 31-day exogenous ketone consumption on running performance, cognitive function, metabolism, body composition, hemodynamics, and mood in recreational runners: a randomized-control trial. Journal of the American Nutrition Association, 2026.
Randomised controlled trial18 recreational runners: 30 g of a ketone ester three times a day for 31 days didn't change 5 km time-trial performance.
doi.org/10.1080/27697061.2026.2636551 - [10]
Jo E, Silva SC, Auslander AT, et al. The effects of 10-day exogenous ketone consumption on repeated time trial running performances: a randomized-control trial. Journal of Dietary Supplements, 2022.
Randomised controlled trial32 endurance-trained adults, 10 days of ketone salts: a first 800 m run didn't change; the ketone group's average over two runs got faster, the placebo group's didn't.
doi.org/10.1080/19390211.2020.1838022 - [11]
Evans M, McSwiney FT, Brady AJ, Egan B No benefit of ingestion of a ketone monoester supplement on 10-km running performance. Medicine and Science in Sports and Exercise, 2019.
Randomised controlled trial8 endurance-trained runners: a ketone ester with carbohydrate made no difference to a 10 km time trial after an hour of running, compared with carbohydrate alone.
doi.org/10.1249/MSS.0000000000002065 - [12]
Whitfield J, Burke LM, McKay AKA, et al. Acute ketogenic diet and ketone ester supplementation impairs race walk performance. Medicine and Science in Sports and Exercise, 2021.
Non-randomised trial18 elite race walkers: after a 5-day ketogenic diet plus a ketone ester, all nine in that group raced 10,000 m about 6% slower. Walkers chose their diet group.
doi.org/10.1249/MSS.0000000000002517 - [13]
Stubbs BJ, Cox PJ, Kirk T, et al. Gastrointestinal effects of exogenous ketone drinks are infrequent, mild, and vary according to ketone compound and dose. International Journal of Sport Nutrition and Exercise Metabolism, 2019.
Randomised controlled trialThree studies of ketone drinks: gut symptoms were mostly mild and short-lived, and high-dose ketone salts caused the most. Authors linked to a ketone drink maker.
doi.org/10.1123/ijsnem.2019-0014 - [14]
World Anti-Doping Agency The Prohibited List. World Anti-Doping Agency, 2026.
RegulatorThe substances and methods prohibited in sport. The list is not exhaustive: a substance not being named does not prove it is allowed.
www.wada-ama.org/en/prohibited-list - [15]
Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. British Journal of Sports Medicine, 2018.
Consensus statementSupplements can contain prohibited substances as undeclared ingredients or contaminants, and athletes are responsible for anything found in their sample.
doi.org/10.1136/bjsports-2018-099027
Who wrote and reviewed this
Written by Grant MacMillan, Editor, RunV. Not yet reviewed by an expert.
Last checked against its references . Next review due . How pages are reviewed · How we grade research
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