Ketone esters
Evidence: weak
Expensive and heavily marketed, but the weight of evidence shows no race-day performance benefit. A possible recovery role is preliminary and does not justify the cost.
Not medical advice
This is a general knowledge base, not medical or dietary advice. If you are injured, unwell or weighing up a supplement or a change to your diet, speak to a doctor, physiotherapist or registered dietitian who knows your situation.
Keep it in proportion
The basics are where the real gains are: consistent volume, sleep and adequate fuelling. Weigh anything below honestly, and do not let a marginal or over-marketed aid pull attention from the things that actually move the needle.
Ketone esters are an expensive, heavily marketed supplement whose claimed race-day performance benefit is not supported by the weight of evidence. The Australian Institute of Sport places ketones in Group B, the “emerging, use only under research conditions” tier, not the proven Group A.
A meta-analysis of eight randomised trials found no acute performance benefit, for either time to exhaustion or time-trials (Brooks et al. 2022). The optimistic early result, a roughly 2% improvement in a cycling time-trial (Cox et al. 2016), came from a single laboratory with commercial ties and was not independently replicated. Independent attempts instead found impairment: a ketone diester made elite cyclists about 2% slower, with gastrointestinal distress in every participant (Leckey et al. 2017). A running study often cited as positive in fact reported a non-significant change (βHB running study).
The one use with a plausible signal is recovery rather than racing: a single small study found that ketone ester taken after sessions sustained a higher training load and attenuated markers of overreaching (Poffé et al. 2019). That is preliminary, from one group, and does not justify the cost, which runs to many pounds per serving against pennies for the proven aids.