Quick Glucuronolactone Summary Points
- Glucuronolactone is most commonly known as a popular component of energy drinks
- Glucuronolactone is a normal human metabolite formed from glucose, but is only present in small amounts in the diet
- In the body it exists as in physiological equilibrium with glucuronic acid
- Therefore supplementation with glucuronolactone boosts glucuronic acid and association phase II glucuronidation
- Supplementation with glucuronolactone may improve liver function through its link with glucuronidation
- Typical doses of glucuronolactone in energy drinks and supplements are generally considered to be safe
What is Glucuronolactone?
Glucuronolactone (D-glucurono-gamma-lactone) is a naturally occurring solid white compound that has applications for bodybuilding and exercise. It is one of the lesser known ingredients, but there is evidence to suggest that it may be useful in increasing both physical and mental performance.
Where Does Glucuronolactone Come From?
Glucuronolactone naturally occurs in the connective tissue (eg tendons, ligaments, cartilage) of humans and animals, as well as in the gums of plants. It is also common ingredient in higher concentrations in energy drinks such as Red Bull.
Glucuronolactone is present in many commercial products as a mixture of active ingredients. These cocktails have been relatively well studied in relation to both physical and mental performance.
Glucuronolactone Benefits for Bodybuilding & Endurance
In physiological trials, glucuronolactone has been shown to inhibit the synthesis of toxic by-products of intensive exercise as well as other negative effects causing fatigue (Tamura et al, 1968). Various studies have investigated products containing glucuronolactone on physical performance. When human subjects were given an energy drink containing a combination of glucuronolactone, caffeine, and taurine, it was found that they experienced improvements in aerobic and anaerobic performance compared to those receiving a control (Alford et al, 2001). When used in a pre workout supplement, glucuronolactone in combination with the aforementioned ingredients resulted in an increase in total repetitions performed. This also led to an increase in an anabolic response among supplemented people (Hoffman et al, 2008). These results were later reproduced and supported by the same group of researchers (Gonzalez et al, 2011). Such results suggest that glucuronolactone may help to increase strength and lean gains when used in conjunction with weight training.
Glucuronolactone Benefits for Mental Performance
It has been reported that not only does glucuronolactone help to improve physical performance, there is also evidence to suggests it helps to increase mental performance. When given an energy drink containing glucuronolactone, subjects showed significant improvements in reaction time, concentration, and memory (Alford et al, 2001).
Glucuronolactone Negatives and Safety
Glucuronolactone has received negative press in the past, because it was rumoured that it caused brain tumours. However, these claims were completely false. As a result of the common use of glucuronolactone, its safety has been extensively studied. Based on a thorough review, the European Food Safety Authority has stated that glucuronolactone in commercial products such as energy drinks is not a safety concern. In fact, it is far more likely that high doses of caffeine show more side effects (EFSA, 2009).
Glucuronolactone Recommended Doses
Doses of 350mg glucuronolactone have been found to be effective for use as a pre workout supplement (Hoffman et al, 2008). The effects of glucuronolactone set in fairly rapidly. It has been reported that consuming a supplement containing glucuronolactone 10 minutes before exercise resulted in improved exercise performance (Hoffman et al, 2008). However, given that glucuronolactone typically occurs with other ingredients, it is recommended for such supplements to be consumed 30 to 45 minutes before a workout, or as indicated by the manufacturer.
Alford et al (2001), The effects of Red Bull Energy Drink on human performance and mood. Amino Acids, 21: 139-150
EFSA (2009), The use of taurine and D-glucurono-gamma-lactone as constituents of the so-called "energy" drinks. doi:10.2903/j.efsa.2009.935
Gonzalez et al (2011), Effect of a pre-workout energy supplement on acute multi-joint resistance Exercise. Journal of Sports Science and Medicine, 10: 261-266
Hoffman et al (2008), Effect of a Pre-Exercise Energy Supplement on the Acute Hormonal Response to Resistance Exercise. Journal of Strength & Conditioning Research, 22: 874-882
Tamura et al (1968), Effects of glucuronolactone and the other carbohydrates on the biochemical changes produced in the living body of rats by hard exercise. Jpn J Pharmacol, 18: 30-38