Where should I apply topical testosterone? March 10, 2026 17:45 Updated Upper arms, shoulders, or inner thighs are most common. Avoid genitals or areas with broken skin. Related articles How long until the application site is safe for female or child exposure? How often do I apply the topical TRT? How often do I inject? How long until I can wash the area or get wet? What testosterone levels can I expect with injectable TRT?