The Truth About Ketone Supplements (Ketone Esters) in Cycling

What Are Exogenous Ketones?

When the body is in a fasting or very low-carbohydrate state, the liver converts fatty acids into ketone bodies, primarily β-hydroxybutyrate (BHB) and acetoacetate (AcAc). These molecules can be used directly as fuel by the brain and muscles, serving as an evolutionary “backup energy system.”

Exogenous ketone supplements bypass the restrictions of a ketogenic diet by directly providing ketone molecules, allowing athletes to maintain high blood ketone concentrations even while simultaneously consuming high carbohydrates. This is the so-called “Dual Fuel” hypothesis.

Product Type Analysis

Ketone Esters

Product	Main Ingredient	Peak BHB per Serving	Taste	Price (Approx.)
HVMN Ketone-IQ	R-1,3-butanediol	1.5-2.0 mmol/L	Slightly bitter	~NT$2,500/10 servings
deltaG / Deltaketone	®-3-hydroxybutyrate ®-1,3-butanediol monoester	3.0-5.0 mmol/L	Extremely bitter	~NT$5,000/3 servings
KetoneAid KE4	BHB diester	2.0-4.0 mmol/L	Bitter	~NT$3,500/3 servings

Ketone Salts

BHB bound to minerals such as sodium, calcium, and magnesium. Blood ketone elevation is lower (typically 0.5-1.0 mmol/L), but they are cheaper and taste better. Most research suggests insufficient evidence for the efficacy of ketone salts.

Current Usage Among Professional Teams

Ketone supplements have sparked significant controversy in the professional road cycling world:

Teams/Riders Known to Use Them

• Jumbo-Visma (now Visma-Lease a Bike): Publicly acknowledged using ketone esters between 2019-2023, particularly during Grand Tours
• Ineos Grenadiers: Began collaborating with deltaG during the Team Sky era; reportedly used during the Chris Froome era
• Soudal Quick-Step: Remco Evenepoel reportedly used them during race preparation

Points of Controversy

• WADA Stance: Ketone supplements are currently not on the prohibited list and are legal supplements
• Opposing Voices: Some teams and riders (such as AG2R’s Romain Bardet) have publicly called for them to be added to the monitoring list
• Health Concerns: Safety data on long-term, high-dose use remains insufficient

Scientific Evidence: For and Against

Studies Supporting Use

Cox et al. (2016), Cell Metabolism

• This groundbreaking study found that a ketone ester + carbohydrate combination improved 30-minute time trial performance by approximately 2% compared to carbohydrates alone
• Mechanism: Ketones serve as an additional fuel source while “sparing” muscle glycogen
• Subjects: Trained cyclists

Poffé et al. (2021), Medicine & Science in Sports & Exercise

• Three weeks of ketone ester supplementation improved recovery markers during a period of overtraining
• Suggests ketones may have greater value for training recovery rather than acute performance

Shaw et al. (2020), Journal of Physiology

• Ketone esters maintained better cognitive function in simulated high-altitude conditions
• Potential applications for mountain stages or high-altitude training camps

Studies Against Use

Leckey et al. (2017), Frontiers in Physiology

• In a 31.7 km time trial, the ketone ester group’s performance actually decreased by 2%
• Most subjects reported severe gastrointestinal distress (nausea, vomiting)

Prins et al. (2020), International Journal of Sport Nutrition

• In trained runners, ketone salt supplementation showed no performance improvement
• Conclusion: The blood ketone elevation from ketone salts is insufficient to produce ergogenic effects

Evans & Egan (2018), Journal of Physiology

• A systematic review noted methodological issues in most positive studies
• Placebo control is difficult (the extremely bitter taste of ketone esters makes blinding challenging)

In-Depth Mechanism Analysis

Why Might It Theoretically Work?

1. Fuel substitution: Ketone oxidation can provide an additional 5-10% of energy, theoretically sparing limited muscle glycogen
2. Reduced lactate production: Ketone metabolism does not go through the glycolytic pathway, potentially reducing lactate accumulation during high-intensity exercise
3. mTOR signaling modulation: BHB may influence recovery-related gene expression through epigenetic mechanisms (HDAC inhibition)
4. Anti-inflammatory effects: Ketones have been shown to inhibit the NLRP3 inflammasome

Why Are Actual Effects Uncertain?

1. Gastrointestinal side effects: High doses of ketone esters almost universally cause nausea, which may offset any metabolic advantage
2. Large individual variability: Ketone utilization efficiency varies greatly between individuals
3. Training status effects: Highly trained athletes may benefit less from ketones because they already possess efficient fat oxidation capacity
4. Unclear dose-response relationship: There is still no consensus on optimal dosage, timing, or the ratio for combining with carbohydrates

Recommendations for Amateur Riders

Reasons Not to Use Them

1. Extremely poor cost-effectiveness: A single serving of deltaG ketone ester costs approximately NT$1,500-2,000, yet the effects are uncertain
2. Foundational nutrition matters more: Most amateur riders cannot even achieve 60g of carbohydrates per hour; spending money on ketone esters is less sensible than getting carbohydrate fueling right first
3. Gastrointestinal risk: The nausea caused by ketone esters could ruin an important race
4. Lack of long-term safety data: As a relatively novel supplement, the effects of long-term use are unknown

If You Still Want to Try

1. Test it during training first: Absolutely do not use it for the first time on race day
2. Start with a low dose: Half a serving (approximately 12.5ml) of ketone ester, and observe gastrointestinal response
3. Combine with carbohydrates: Ketones cannot replace carbohydrates; they serve as an additional “third fuel”
4. Choose products with third-party testing: Ensure they are free of prohibited substances (Informed Sport certification)

Conclusion

Ketone supplements are one of the most cutting-edge topics in sports nutrition. The scientific evidence is currently contradictory—there is an exciting theoretical foundation, but actual performance data is mixed. For most cyclists, focusing on well-validated strategies (carbohydrate fueling, caffeine, adequate sleep) is a smarter investment. Ketone supplements may be the trend of the future, but until more high-quality research emerges, they remain an option “worth watching but not rushing to adopt.”

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References: Cox, P.J. et al. (2016). Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes. Cell Metabolism; Poffé, C. et al. (2021). Ketone ester supplementation blunts overreaching symptoms during endurance training overload. Journal of Physiology.

Related Reading

• Ketone Esters 2026 New Evidence: Should You Use Them or Not?
• The Effect of Ketone Esters on Cycling Time Trials: Latest RCT
• Ketone Ester Drinks: Does the Expensive “Fourth Fuel” Actually Work?
• The Ketone Supplement Controversy: Why the UCI Does Not Recommend Them, and What the Evidence Actually Says