The body does not actually need to purge toxins from the armpits in the form of perspiration. Sweat is made up of a combination of 99.9% water, sodium, potassium and magnesium. Sweating during exercise serves as a cooling mechanism in order to maintain a normal body temperature. The application of antiperspirants to the underarms does not interfere with this cooling process, as only around 1% of sweat glands are located in the armpits. Perspiration is more noticeable in these regions simply because there is less air ventilation and so it is more difficult for sweat to evaporate. Controversy surrounding antiperspirant use and breast cancer risk remain unsubstantiated. Extensive studies have been conducted on the risk factors for developing breast cancer following antiperspirant use and none support this assumption. In addition, the U.S. Food and Drug Administration does not have any evidence or data to suggest that underarm antiperspirants or deodorants promote cancer.