Glycerol, also known as glycerin, is an alcohol compound most commonly found in the diet as a component of fat or triglycerides. The glycerol serves as the backbone onto which fatty acid molecules are attached. Commercial preparation of glycerol can be obtained by hydrolysis (removal) of the fatty acids from the glycerol molecule.
• Increases blood volume
• Increases water holding capacity of cells
• Enhances temperature regulation
• Improves exercise performance in the heat
• Reduces dehydration
Glycerol is proposed to help “hyperhydrate” the body by increasing blood volume levels and helping to delay dehydration.
Glycerol Scientific Support
At least a few studies support the theory that glycerol added to fluids will increase tissue hydration compared to drinking fluid without glycerol added. Following glycerol consumption, heart rate and body core temperature are lower during exercise in the heat, suggesting an ergogenic (performance enhancing) effect. In long duration activities, a larger supply of stored water may lead to a delay in dehydration and exhaustion.
Straight (undiluted) glycerin is not recommended for internal consumption, but no significant adverse side effects are associated with glycerin diluted with fluids. In some subjects, glycerol consumption may lead to headaches or nausea. Individuals in whom increased blood volume may be undesirable, including conditions such as pregnancy, high blood pressure, diabetes, and kidney disease, should avoid glycerol supplementation.
For endurance athletes engaged in strenuous training or competition in hot environments, consumption of glycerol containing beverages may help hydrate tissues, increase blood volume, and delay fatigue and exhaustion associated with dehydration.
Glycerol dosage relates to the amount of total body water so bigger people have more body water and require more glycerol to obtain the desired effect. Approximately 1 g of glycerin per kilogram (2.2 lb) of body weight is diluted in 20 to 25 ml of liquid. A 70 kg man (154 lb), therefore, would need 70 g of glycerin diluted in 1,400 to 1,750 ml of fluid (about 1 to 2 liters of fluid). The mixture should be consumed slowly over the course of one to two hours prior to exercise in the heat.