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NCT Number: NCT06746805

The Effect of Acute Ketone Monoester Supplementation on Glucose Oxidation During Exercise

The purpose of this study is to examine the effect of exogenous ketone body supplementation on carbohydrate metabolism during exercise. In a randomized, crossover, and double-blind study, 20 endurance trained adult males and females aged 18-50 years, will ingest carbohydrates with either a ketone monoester supplement before and throughout a 3-hour exercise session or carbohydrates with a flavour-matched ketone-free placebo. The main aim of this study is to compare the exogenous carbohydrate oxidation rates during exercise between the ketone monoester and placebo conditions.

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Key information

Conditions

Exercise Metabolism

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maastricht University Medical Center+

Maastricht, Limburg, 6229ER, Netherlands

Location status: Recruiting

Location contact

LJC van Loon, Professor

CONTACT

[email protected]

0031433881397

Philippe Pinckaers, MSc

SUB_INVESTIGATOR

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 18-50 years of age
  • Trained cyclist/triathlete (VO2peak > 55 ml/kg/min for males and >48 ml/mg/min for females)
  • Healthy as per medical history and investigator's/physician's judgement
  • Having given written informed consent

Exclusion criteria

  • Use of medication that could impact study outcomes and/or interfere with the expected mechanism of action of ketone supplements (e.g. Chronic use of gastric acid suppressing medication, statins, corticosteroids)
  • Smoking
  • Diagnosed acute or chronic medical conditions that, in the opinion of the investigator, could impact study outcomes (e.g. Diabetes mellitus)
  • Diagnosed musculoskeletal disorders
  • Adhering to a carbohydrate restrictive diet
  • Participation in another study at the same time
  • Blood donation in the 2 months before the first experimental trial
  • Plasma donation in the 2 weeks before the first experimental trial
  • Males: VO2peak <55 ml/min/kg body mass
  • Females: VO2peak <48 ml/min/kg body mass
  • Females: pregnancy

Treatment and study plan

CHO+KETONE

Dietary Supplement

Sports drink containing glucose and ketone mono-esters

CHO+PLACEBO

Dietary Supplement

Sports drink containing glucose and placebo

Primary outcomes

  1. Exogenous carbohydrate oxidation rate

    Time frame: Acute:during 3 hours of exercise

    Exogenous carbohydrate oxidation rate during exercise measured by 13C enrichment in breath. CHO+KETONE vs CHO+PLACEBO condition

Secondary outcomes

  1. Endogenous carbohydrate disappearance rate

    Time frame: Acute:during 3 hours of exercise

    Endogenous carbohydrate disappearance rate during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

  2. Exogenous carbohydrate disappearance rate

    Time frame: Acute:during 3 hours of exercise

    Exogenous carbohydrate disappearance rate during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

  3. Total carbohydrate disappearance rate

    Time frame: Acute:during 3 hours of exercise

    Total carbohydrate disappearance rate during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

  4. Exogenous carbohydrate appearance rate

    Time frame: Acute:during 3 hours of exercise

    Exogenous carbohydrate appearance rate during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

  5. Endogenous carbohydrate appearance rate

    Time frame: Acute:during 3 hours of exercise

    Endogenous carbohydrate appearance rate during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

  6. Total carbohydrate appearance rate

    Time frame: Acute:during 3 hours of exercise

    Total carbohydrate appearance rate during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

  7. Plasma glucose enrichments during exercise

    Time frame: Acute:during 3 hours of exercise

    Plasma glucose enrichments during exercise measured by stable isotope tracer methodology. CHO+KETONE vs CHO+PLACEBO condition

Other outcomes

  1. Total carbohydrate oxidation

    Time frame: Acute:during 3 hours of exercise

    Total carbohydrate oxidation during exercise, measured indirectly by using traditional stoichiometric calculations of carbohydrate oxidation. CHO+KETONE vs CHO+PLACEBO condition

  2. Blood parameters

    Time frame: Acute:during 3 hours of exercise

    Plasma glucose, insulin, glycerol, free fatty acids, and ketone body concentrations (including area under the curve) following drink ingestion. CHO+KETONE vs CHO+PLACEBO condition

  3. Exercise economy during cycling

    Time frame: Acute:during 3 hours of exercise

    Exercise economy during the exercise trial. CHO+KETONE vs CHO+PLACEBO condition, will be determined based on the amount of work performed during cycling (workload), and the amount of energy expenditure as measured by indirect calorimetry.

  4. Exercise heart rate

    Time frame: Acute:during 3 hours of exercise

    Heart rate during exercise. CHO+KETONE vs CHO+PLACEBO condition

Study contacts

Contact information is provided by the study sponsor or research team.

Luc van Loon, PhD

CONTACT

[email protected]

0031 43 388 1743

Sponsors and collaborators

Lead sponsor

Maastricht University Medical Center

Other

Registry information

Official study title

The Effect of Acute Ketone Monoester Supplementation on Glucose Oxidation During Exercise Performed With High Rates of Carbohydrate Ingestion in Trained Cyclists

Acronym: KETONE

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Dec 24, 2024
Registry last updated
Sep 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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