Supplement analysis backed by scientific evidence · PT

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Limited evidencePhysical performance

Ketone Esters

Drinks that raise blood ketones without a ketogenic diet, sold as an alternative fuel for endurance. Despite a striking metabolic effect, controlled trials do not show a performance benefit and some show impairment.

Evidence last reviewed: August 2026

What the science says

  • Endurance performance Limited evidence

    A systematic review and meta-analysis of randomized controlled trials of acute ketone supplementation found no overall benefit for exercise performance. A separate systematic review reached the same conclusion.

  • Possible impairment at higher intensities Limited evidence

    A randomized crossover trial in trained cyclists found that acute ketone monoester ingestion impaired 20-minute time-trial performance. Increased cardiorespiratory stress during submaximal cycling has been reported by the same group.

  • Recovery and training tolerance Limited evidence

    Some small trials suggest ketone esters may help with overreaching or post-exercise recovery markers, but these are preliminary, few in number, and not consistently replicated.

Dosage & safety

Studied doseResearch protocols used roughly 250–750 mg/kg of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate, taken 30–60 minutes before or during exercise. There is no dose shown to reliably improve performance.
SafetyGastrointestinal distress, nausea and reflux are common, especially at higher doses and during exercise. Ketone esters taste extremely unpleasant and are expensive. People with type 1 diabetes should not use them without medical supervision, and they are not a substitute for carbohydrate during competition.

Scientific references

Where to buy

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