Preventing secondary exposure to women from men applying a novel Nestorone/testosterone contraceptive gel
Background: Testosterone (T)/Nestorone (NES) combination gel is a potential transdermal male contraceptive that suppresses gonadotropins and spermatogenesis. Transfer of transdermal T from men to women can be prevented by washing or covering application sites with clothing. Objectives: We hypothesized that showering or wearing a shirt over gel application sites would prevent secondary exposure of T and NES to a woman after close skin contact. Materials and methods: Twelve healthy male and 12 healthy female participants were recruited. Men applied T/NES 62 mg/8 mg gel to their shoulders and upper arms. Two hours after application, female partners rubbed the application site for 15 min. Exposure in the female partner was assessed under three conditions: a shirt covered the application site; the man showered prior to skin contact; or without intervention to reduce transfer. Serum T and NES concentrations were measured by LC‐MS/MS in serial blood samples for 24 h after gel exposure. Main Outcomes: Change in female serum T and NES levels as measured by average concentration over 24 h (C_avg). Results: Median female serum T C avg was 23.9 ng/dL (interquartile range, 19.3, 33.9) with the shirt barrier and 26.7 ng/dL (20.7, 33.9) after showering, which was higher than baseline 20.9 ng/dL (16.7, 25.0), both p < 0.03) but lower than without intervention (58.2 ng/dL [30.9, 89.1], both p < 0.01). Female serum NES C_avg and maximum concentration were below the lower limit of quantification with the shirt barrier and after showering, but increased without intervention in six of 12 women (maximum concentration < 60 pg/mL). Men had lower average serum NES levels after showering (47 pg/ml [20, 94] compared to no intervention (153.3 pg/mL [51, 241], p < 0.02). Conclusion: Secondary transfer of T and NES occurs after intensive skin contact with the gel application site. Secondary transfer is decreased by a shirt barrier or showering before contact.
Yuen, F., S. Wu, A. Thirumalai, Ronald S. Swerdloff, Stephanie T. Page, Peter Y. Liu, Clint Dart, H. Wu, Diana Blithe, Régine Sitruk-Ware, J. Long, F. Bai, L. Hull, William J. Bremner, Bradley D. Anawalt, and Christina Wang. 2019. "Preventing secondary exposure to women from men applying a novel Nestorone/testosterone contraceptive gel," Andrology 7(2): 235–243.