In a clinical study conducted to evaluate the effect of hand washing on the residual amount of testosterone, 36 healthy male subjects received 50 mg of testosterone from 5 g of Vogelxo on a hand and applied testosterone gel to the upper arm and shoulder of one side. Subjects washed their hands with liquid soap and warm water immediately after drug application. Then the hand was allowed to air dry or patted dry with a cloth towel. A skin swab sample was collected and analyzed for testosterone content. A mean (SD) of () to () µg of residual testosterone (., 99% reduction compared to when hands were not washed) was recovered after washing hands with liquid soap and warm water.