In a randomized controlled trial published in the European Journal of Sport Science, researchers explored the effects of post-exercise R-1,3-butanediol (BDO) supplementation on various markers of fatigue and recovery during a multi-stage mountain bike race. The study involved 18 trained mountain bikers who participated in the 2025 Absa Cape Epic, an 8-day endurance event.
The participants were divided into two groups, receiving either BDO or a placebo. The aim was to assess whether BDO could improve physiological strain, dietary intake, hydration, cognitive function, sleep, and subjective recovery during the race. The study monitored heart rate, energy intake, sleep metrics, cognitive performance, and subjective stress-recovery throughout the event.
Results indicated that BDO induced mild post-stage ketosis, with β-hydroxybutyrate levels reaching approximately 1.0 mM from the first stage onwards. However, despite this mild ketosis, both groups exhibited similar trends in physiological strain. Specifically, participants showed lower exercise heart rates, increased resting heart rates, higher energy and carbohydrate intake, and slower reaction times by stage 6, suggesting accumulating fatigue.
Importantly, the study found that BDO did not significantly alter any of these physiological effects compared to the placebo group. This outcome suggests that the modest ketosis achieved with BDO supplementation was ineffective in enhancing recovery or reducing fatigue under the real-world conditions of an endurance race.
The authors emphasized the need for more ecologically valid evaluations of exogenous ketosis strategies, highlighting that the formulation and context of use are critical factors in determining efficacy.
What this study does not show
This study does not demonstrate any significant benefits of R-1,3-butanediol supplementation on fatigue or recovery markers in trained mountain bikers during a multi-stage race.
Evidence scorecard
- Analytic validity: established
- Clinical validity: established
- Clinical utility: not established
The evidence class is human_rct.