The truth about ketone supplements in cycling

Ketone drinks are back in headlines every season. Some riders swear by them for stage races and hard training blocks; others try one bottle and swear never again. Here is a clear, research-grounded look at what exogenous ketones can and cannot do for performance, recovery, and your gut.

Bottom line: ketone supplements are not a substitute for carbohydrates and training. They may help in specific situations, but they can also hurt if used poorly.

What ketone supplements are (and are not)

Exogenous ketones raise blood beta-hydroxybutyrate (BHB) without a ketogenic diet. There are two main types:

• Ketone monoesters (KE): the form used in most performance studies. Faster, higher BHB levels, expensive, often better studied.
• Ketone salts (KS): BHB bound to minerals (e.g., sodium, potassium). Lower BHB rise, more gut issues due to mineral load.

Typical goals riders chase include steady-state power on long rides, back-to-back day recovery, and sharper cognition when fatigued. The evidence is mixed, context-specific, and dose-dependent.

Performance: where ketones help, hurt, or do nothing

Across controlled trials and recent reviews, here is the practical picture for cyclists:

Mechanistically, raising BHB tends to shift fuel use toward more fat and ketone oxidation and slightly away from carbs. That is not ideal when the session demands high glycolytic flux (e.g., above threshold). For sub-threshold work, the effect is usually neutral if you keep carbohydrate intake high.

Recovery: the most promising use-case

When used after hard rides and combined with adequate carbohydrates and protein, ketone monoesters have shown:

• Glycogen resynthesis: some studies report a modest increase compared with carbs alone, others find no difference. Not a guaranteed effect.
• Protein balance: reduced muscle protein breakdown markers in certain protocols.
• Training load tolerance: in overreaching models, riders taking ketones post-ride and before sleep saw better sleep quality and maintained performance slightly better. Replication is mixed.

If you are stacking long days (camps, stage races, ultra prep), recovery is the most defensible reason to trial ketones—provided your carbohydrate intake is already optimal.

Gut tolerance: the make-or-break factor

GI side effects are common and often determine whether ketones help or hurt your watts:

• Salts: higher risk of nausea, bloating, and urgent bathroom stops due to mineral load.
• Esters: fewer mineral issues but still cause nausea or belching for many; taste can be aversive.
• Dose matters: big single doses are more likely to cause problems, especially during intense riding.

Ways to improve tolerance:

• Start small on an easy ride. Do not debut before intervals or a race.
• Use well-chilled, diluted servings and sip rather than slam.
• Pair with carbs; avoid taking ketones on an empty stomach before hard efforts.
• Avoid combining with highly acidic or carbonated drinks.

How to trial ketones without wrecking a session

These are conservative, rider-tested protocols grounded in the literature. Always prioritize carbohydrates first.

Before a long, mostly sub-threshold ride

• Dose: 250–350 mg/kg of a ketone monoester 20–30 minutes pre-ride (about 17–24 g KE for a 70 kg rider).
• Carbs: 60–90 g/h (up to 100–120 g/h if well trained and gut-trained).
• Aim: steady endurance in Z2–low Z3. Do not use before VO2max or sprint sessions.

After hard sessions or on camp days

• Dose: 100–200 mg/kg KE within 30 minutes post-ride.
• With recovery nutrition: 1.0–1.2 g/kg carbs plus 0.3 g/kg protein.
• Optional: a small second dose before sleep on heavy blocks if tolerated.

During exercise

• Generally not recommended for races or hard interval days due to GI risk and possible power suppression in high intensity.
• If experimenting on long LSD, keep doses small and maintain normal carb intake.

Who might benefit—and who should skip

• Consider trialing if you: do multi-day events, training camps, or ultras; are already nailing carbs, hydration, and sleep; are willing to test tolerance well before any key event.
• Likely skip if you: focus on crits, short TTs, or sprint-heavy racing; struggle with GI sensitivity; have not yet optimized carb fueling, recovery protein, or pacing in your training zones.

Safety, legality, and practicalities

• Legality: allowed by anti-doping rules as of 2025.
• Cost: high per dose; weigh against obvious wins like adequate carbs, caffeine timing, and sleep.
• Health: if you have metabolic, renal, or significant GI conditions, speak with a clinician first. Avoid in minors. Do not replace prescribed nutrition.
• Monitoring: some riders check blood BHB; 1–3 mmol/L is typical after a KE dose. Chasing higher numbers is not better for performance.

Coach’s checklist: make ketones the 5% after the 95%

• Fuel training first: 60–120 g/h carbs on long rides, practice your mix, and track gut tolerance.
• Hit the basics: 0.3 g/kg protein post-ride, 7–9 h sleep, hydration and sodium matched to sweat.
• Train specifically: spend time in the right training zones for your goals; build FTP with consistent volume and structured intensity.
• Only then consider ketones for specific scenarios like camps or ultra prep—and test thoroughly.

Used thoughtfully, ketones can be a niche tool for certain riders and days. Used carelessly, they are an expensive way to go slower.