Ketone esters and ketone salts
A meta-analysis of 13 trials found no change in exercise performance with ketone esters or salts. Recovery measures also did not change. Blood glucose fell by about 0.5 mmol/L after ingestion. Pooled trials report modest cognitive gains and higher ejection fraction in heart failure. Gut discomfort accompanied a slower time trial in elite cyclists.
- Status
- Sold as foods and dietary supplements in the US.
- Also called
- exogenous ketones, ketone monoester, (R)-3-hydroxybutyl (R)-3-hydroxybutyrate, ketone diester, 1,3-butanediol acetoacetate diester, ketone salts, beta-hydroxybutyrate, BHB, β-hydroxybutyrate, D-BHB
- Taken for
- endurance, exercise performance, recovery, focus, cognition, blood sugar, appetite, heart health, ketosis without dieting
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help3
- ModerateShown to lower blood glucose about 0.47 mM after single doses, more with monoesters than salts.
- ModerateShown to improve cognitive performance modestly over placebo in healthy adults and people with conditions such as Alzheimer's disease, more at higher doses.
- ModerateShown to raise ejection fraction about 3% in patients with heart failure, and about 4% with reduced ejection fraction. Hospitalization and death were not pooled.
What people take it for, and what was found
Shown to help3
Blood glucose
Shown to lower blood glucose about 0.47 mM after single doses, more with monoesters than salts.
The numbers and sources
- Effect
- Compared with placebo, exogenous ketones raised blood BHB by 1.98 mM (95% CI 1.52 to 2.45) and lowered blood glucose by 0.47 mM (95% CI -0.57 to -0.36). Monoesters had larger effects than salts [4].
- Population
- 43 trials with 586 participants [4].
- Sources
- [4]
- Caveats
- Almost all trials were single doses. Evidence on longer use was limited [4].
Cognition
Shown to improve cognitive performance modestly over placebo in healthy adults and people with conditions such as Alzheimer's disease, more at higher doses.
The numbers and sources
- Effect
- Across 29 trial arms (1,117 participants), exogenous ketones improved cognitive performance over placebo (SMD 0.29, 95% CI 0.16 to 0.41). Higher daily doses were associated with larger effects [5].
- Population
- Healthy adults and people with neuropsychiatric conditions including Alzheimer's disease [5].
- Sources
- [5]
- Caveats
- One meta-analysis pooling varied tests, populations and formulations.
Heart function in heart failure
Shown to raise ejection fraction about 3% in patients with heart failure, and about 4% with reduced ejection fraction. Hospitalization and death were not pooled.
The numbers and sources
- Effect
- Across 6 RCTs, ketone supplementation raised left ventricular ejection fraction by 3.12% (95% CI 0.95 to 5.30) and by 4.25% in heart failure with reduced ejection fraction. Cardiac output rose by 1.24 L/min in that group [6].
- Population
- Patients with heart failure [6].
- Sources
- [6]
- Caveats
- Small cohorts with varied treatment durations. Hospitalization and death were not pooled.
Not shown to help3
Exercise performance
Not shown to change exercise performance in sprints to events of about 50 minutes, with either ketone esters or salts.
The numbers and sources
- Effect
- Across 13 RCTs, acute ketone supplementation did not change overall performance (Hedges' g -0.05, 95% CI -0.30 to 0.20), endurance time trials (g -0.04), ketone esters (g -0.07) or ketone salts (g -0.02) [1]. A separate review of 10 RCTs found 3 positive, 10 null and 3 negative outcomes among 16, with high heterogeneity [2].
- Population
- Sprints to events of about 50 minutes [1]; 112 participants, 109 of them men [2].
- Sources
- [1], [2]
- Caveats
- Ultra-endurance events were not covered [1]. Nearly all participants were men [2]. The second review was funded by the US Army [2].
Recovery after exercise
Not shown to change muscle soreness, glycogen refilling or creatine kinase after exercise in active adults.
The numbers and sources
- Effect
- Across 7 pooled studies, muscle soreness (SMD 0.39, 95% CI -0.29 to 1.07) and glycogen resynthesis did not differ from control. Post-exercise lactate was slightly higher with ketones (MD 0.34 mmol/L, 95% CI 0.02 to 0.66). Creatine kinase did not change [3].
- Population
- 16 studies reviewed, mostly physically active men [3].
- Sources
- [3]
- Caveats
- Exploratory meta-analysis of few studies.
Blood pressure
Not shown to change systolic or diastolic blood pressure, with single doses or longer use.
Doses studied
A kinetics study gave the monoester at 140, 357 or 714 mg per kg as single doses and three times a day for 5 days, up to 2.14 g per kg per day [8]. Metabolic studies gave drinks delivering about 12 or 24 g of BHB [9]. A cycling trial gave a ketone diester at 2 × 250 mg per kg before a time trial [10].
Risks
Reported risks2
Gut discomfort and slower performance
One small trial found a ketone diester slowed a cycling time trial by 2% in elite cyclists, with gut discomfort.
The numbers and sources
- Effect
- In 10 elite cyclists, a ketone diester taken before a 31 km time trial slowed performance by 2% (±1%), with gut discomfort and higher perceived effort [10]. At the highest monoester dose, some gastrointestinal effects were reported when large volumes of milk-based drink were consumed [8].
- Population
- Professional male cyclists [10]; healthy adults [8].
- Sources
- [8], [10]
- Caveats
- Different ketone compounds. The kinetics study did not report symptom rates in its abstract.
Blood and urine pH, and the L-isomer in salts
Small studies found the monoester lowered blood pH slightly and ketone salts raised urine pH, with blood electrolytes staying normal.
The numbers and sources
- Effect
- The monoester lowered blood pH by 0.10. Ketone salts raised urinary pH from 5.7 to 8.5. Ketone salt drinks contained 50% L-BHB, which stayed elevated in blood for over 8 hours. Blood electrolytes stayed normal [9].
- Population
- Healthy volunteers in three metabolic studies [9].
- Sources
- [9]
- Caveats
- Short studies. Effects of repeated use were not measured.
Checked, no increase found1
Higher resting heart rate
Small trials found resting heart rate did not rise significantly overall, though one found lower heart rate variability after a monoester dose.
The numbers and sources
- Effect
- Resting heart rate tended to rise (SMD 0.17, 95% CI -0.14 to 0.47), and higher supplement doses were associated with larger increases [7]. In 18 healthy adults, 0.3 or 0.6 g/kg of a ketone monoester lowered two heart rate variability measures of vagal activity (pRR50 and RMSSD) at 45 and 120 minutes against placebo [11]. In 19 healthy adults, 0.4 g/kg did not change resting heart rate, blood pressure or muscle sympathetic nerve activity, at rest or under stress [12].
- Population
- 187 participants in 10 studies [7]. Healthy adults aged about 23 in two crossover trials [11][12].
- Sources
- [7], [11], [12]
- Caveats
- The overall change was not significant. The dose relationship came from meta-regression [7]. The crossover trials gave single doses [11][12].
Claims tested and not found
- That ketone supplements improve exercise performance. Pooled trials found no change for esters or salts [1].
- That ketone supplements speed recovery. Soreness, glycogen resynthesis and creatine kinase did not differ from control [3].
- That ketone supplements lower blood pressure. Systolic and diastolic pressure did not change [7].
Sources
- Valenzuela PL, Morales JS, Castillo-García A, et al. Acute Ketone Supplementation and Exercise Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. International Journal of Sports Physiology and Performance. 2020. https://doi.org/10.1123/ijspp.2019-0918
- Margolis LM, O'Fallon KS. Utility of Ketone Supplementation to Enhance Physical Performance: A Systematic Review. Advances in Nutrition. 2020. https://doi.org/10.1093/advances/nmz104
- Bomans S, Jimenez Garcia B, Leemans L, et al. Effects of exogenous ketones on post-exercise recovery: A systematic review and meta-analysis. Journal of Sports Sciences. 2026. https://doi.org/10.1080/02640414.2026.2750608
- Falkenhain K, Daraei A, Forbes SC, et al. Effects of Exogenous Ketone Supplementation on Blood Glucose: A Systematic Review and Meta-analysis. Advances in Nutrition. 2022. https://doi.org/10.1093/advances/nmac036
- Bonnechère B, Stephens EB, Boileau AC, et al. The effect of exogenous ketone bodies on cognition across health and disease: a systematic review and meta-analysis. Frontiers in Nutrition. 2026. https://doi.org/10.3389/fnut.2026.1802531
- Liao LP, Church LA, Melville H, et al. Effect of ketone supplementation, a low-carbohydrate diet and a ketogenic diet on heart failure measures and outcomes: a systematic review and meta-analysis. Heart. 2025. https://doi.org/10.1136/heartjnl-2025-326082
- Marcotte-Chénard A, Tremblay R, Falkenhain K, et al. Effect of Acute and Chronic Ingestion of Exogenous Ketone Supplements on Blood Pressure: A Systematic Review and Meta-Analysis. Journal of Dietary Supplements. 2023. https://doi.org/10.1080/19390211.2023.2289961
- Clarke K, Tchabanenko K, Pawlosky R, et al. Kinetics, safety and tolerability of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate in healthy adult subjects. Regulatory Toxicology and Pharmacology. 2012. https://doi.org/10.1016/j.yrtph.2012.04.008
- Stubbs BJ, Cox PJ, Evans RD, et al. On the Metabolism of Exogenous Ketones in Humans. Frontiers in Physiology. 2017. https://doi.org/10.3389/fphys.2017.00848
- Leckey JJ, Ross ML, Quod M, et al. Ketone Diester Ingestion Impairs Time-Trial Performance in Professional Cyclists. Frontiers in Physiology. 2017. https://doi.org/10.3389/fphys.2017.00806
- Thiessen J, Rourke A, Pocchi G, et al. Acute exogenous ketone monoester supplementation decreases indices of cardiac vagal modulation in a dose-dependent manner in healthy adults. Applied Physiology, Nutrition, and Metabolism. 2026. https://doi.org/10.1139/apnm-2025-0394
- Seto E, Nardone M, Thiessen JS, et al. Effects of acute ketone monoester ingestion on heart rate, blood pressure and muscle sympathetic nerve activity at rest and stress in healthy adults. Physiological Reports. 2025. https://doi.org/10.14814/phy2.70584