Journal Title (Medline/Pubmed accepted abbreviation): Br. J. Sports Med.
Page numbers: 456-458
doi (if applicable): 10.1136/456 bjsm.2011.084988
Glycerol. Glycerol is a three-carbon molecule that serves as the backbone of triglycerides. It is found naturally in foods that contain triglycerides and is also added to foods to achieve more favorable textural and sensory properties. This small molecule has high osmotic properties, meaning that it binds water very strongly. In sports performance, it is added to some beverages in order to prevent dehydration. Success has been shown with doses of 1-1.5 g glycerol per kg of body weight with 25-35 mL of fluid per kg of body weight. (This is equivalent to 85-127.5 g glycerol in 2.1- 3.0 L of water for an 85 kg = 187 lb. person.) This strategy has shown retention of 600 mL to 1 L of water compared to a dose of pure water. Some side effects include hyperhydration, nausea, headache, or gut discomfort. Glycerol was recently placed on the list of prohibited substances for the 2011 World Anti-Doping Agency for its “plasma expanding” properties. However, it is unclear how testing procedures will distinguish between normal dietary intake of glycerol and specific glycerol supplementation.
Guarana. Guarana contains many compounds, one of which is guaranine (also known as caffeine). Guarana is a potent source of caffeine; guarana seeds contain about 2 times the amount of caffeine as coffee beans. Guarana contains other compounds that enhance the stimulating effects of caffeine, including theobromine and theophylline. Therefore, guarana is often found in energy drinks.
Hydroxycut. Hydroxycut is a weight loss supplement that includes caffeine and Cissus quadrangularis (CQ), a plant from the grape family, in addition to other plant ingredients. There have not been any peer-reviewed, scientific articles reporting the safety or efficacy of hydroxycut. There also have not yet been large scientific studies performed to assess the efficacy or safety of the individual botanical agents for weight loss. Small, pilot studies, mostly funded by the Hydroxycut manufacturer, have shown success in the current (May 2011) formulation of Hydroxycut in weight loss, but more research is necessary to assure safety and efficacy of Hydroxycut. It was noted by the authors of this review that a previous formulation of Hydroxycut (containing hydroxycitric acid extracted from Garcinia cambogia fruit, chromium, and Camellia sinensis (green tea)) was removed from the market due to 23 cases of hepatotoxicity and 1 death.