A study conducted by University of California-San Francisco has published that weight loss supplements containing ephedra and guarana changes the cardiovascular system by increasing heart beat rate and blood pressure. It also has negative influence on glucose and potassium homeostasis.
The study spearheaded by Dr. Christine A. Haller and colleagues from the above university took the experimental group of 16 healthy adults. Two tests were performed with this set of people. Supplements taken were Xenadrine RFA and the other a combination of two supplements. Xenadrine RFA contained 25.4 mg ephedra alkaloids and 85 mg caffeine. The other contained 23.2 mg ephedra alkaloids and guarana containing 167 mg caffeine.
The results revealed that repeated intakes of supplements had bad effects on the cardiovascular system. The results published in the June, 2005 issue of Clinical Pharmacology and Therapeutics said that weight loss supplements containing ephedra and guarana may change cardiovascular and metabolic conditions. These in turn prove harmful to obese people with already have high blood pressure, clogged arteries, or glucose intolerance. Therefore ephedra and guarana could worsen obesity-related conditions such as insulin resistance and metabolic syndrome, according to the study.
Source: Clinical Pharmacology and Therapeutics June, 2005