Amount of Testosterone on Laundered Clothing After Use of Testosterone Topical 2% Solution by Healthy Male Volunteers

Testosterone 2% solution (Axiron) applied to armpit(s) is used for replacement therapy in men with a deficiency of endogenous testosterone. To determine the amount of testosterone on subjects' T-shirts 12 hours after applying testosterone solution, the residual testosterone on subjects' T-shirts after laundering, and the testosterone transferred to unworn textile items during laundering with worn T-shirts. Healthy males ≥18 years old applied 2 × 1.5 mL of testosterone 2% solution to both axillae (total testosterone dose: 120 mg) and dressed in cotton long-sleeved T-shirts after a ≥3-minute waiting period. T-shirts were worn 12 hours before being removed and cut into halves, after which a 10 × 10 cm sample of each armpit area was excised for testosterone quantification before or after laundering with samples of unworn textiles. Testosterone on worn T-shirts before and after laundering, and on unworn textiles laundered with the worn T-shirts. Twelve subjects enrolled and completed, with only minor adverse events. Mean testosterone in unwashed worn T-shirts was 7603 μg, with high between-subject variability (3359 μg to 13,069 μg), representing 13% of the dose to 1 armpit. Mean testosterone in worn, laundered T-shirts was 260 μg (7.55 μg to 1343 μg), representing 3% of the dose to 1 armpit. Mean transferred testosterone to other textiles during laundering ranged from 69 μg on texturized Dacron 56T Double to 10,402 μg on 87/13 nylon/Lycra knit, representing 0.0382% to 5.78% of the dose to 1 armpit. Thirteen percent of the testosterone applied to axillae was transferred to T-shirts during wear. Ninety-seven percent of the transferred testosterone was removed from the T-shirts during washing, some of which was then absorbed to various degrees by other textiles. Clinical implications of these findings and biological activity of the remaining/transferred testosterone are unknown.