Every week, I filter through the latest sports science research. The goal is to find the most interesting new research, break down the findings, and turn them into actionable insights you can use in your training.
Ketone supplements are marketed to endurance athletes as a way to improve performance and support training adaptations. But do they actually help when you're already following a demanding training program?
A new study put this to the test during a six-week altitude training block with recreational cyclists.
The study
In this study, researchers recruited 18 recreationally active cyclists, nine men and nine women, for a five-week altitude training program followed by a one-week taper.
The cyclists followed a live-high, train-low protocol, spending time in simulated altitude conditions equivalent to 2,000–3,000 metres while training at lower elevations.
Half the participants took a ketone monoester drink after exercise and again before bed, for a total of 50 g per day. The other half took a calorie-matched placebo.
The training worked. The ketones didn't add anything.
By the end of the taper, both groups had improved their 30-minute time trial power by 9%. Their VO₂ max increased by 8%, and total hemoglobin mass increased by 8.77%.
But the cyclists taking ketones didn't improve any more than those taking the placebo.
There was also an interesting finding in the repeated sprint tests: performance improved in the placebo group but not in the ketone group. With only nine participants per group, we can't conclude that ketones harmed sprint performance, but the results certainly don't suggest an added benefit.
The researchers also found no changes in muscle capillarization or the muscle proteins VEGF and HIF-1α that could be attributed to the ketone supplement.
Why it matters
If you're an endurance athlete, you know how much goes into a serious training block. Altitude camps, structured workouts, recovery, and the logistics of getting everything right all take time and money.
Ketone supplements are another potential expense, often marketed around their ability to improve endurance performance or enhance training adaptations.
This study suggests that, at least during this type of altitude training program, adding ketones didn't improve the results.
The key takeaway is that a supplement can have an interesting physiological rationale without producing better performance in practice. What matters is whether it improves the outcome you're training for.
My thoughts
The results I find most interesting are the improvements both groups achieved without any added benefit from ketones. A 9% increase in 30-minute time trial power is substantial, and hemoglobin mass increased by nearly 9% across the training block.
Of course, this was a small study involving recreationally active cyclists, so we shouldn't assume the same results would apply to elite athletes, other sports, or different supplementation protocols. It also doesn't prove that ketones have no benefit in every situation.
But it is a useful reminder to look beyond the marketing.
My takeaway? If you're planning a big training block, prioritize the things that support consistent training: a well-designed program, adequate food, sufficient recovery, and supplements like dietary nitrates with evidence for your specific goal.
Before spending money on an expensive add-on, ask yourself a simple question: Is there good evidence that this will improve my results, or am I just hoping it will?
Sometimes, the best investment isn't another supplement. It's getting more out of the training you're already doing.