Trans men are adults assigned female at birth transitioning to or adopting a masculine gender identity. The Tavistock & Portman GIC shared-care prescribing guidance is outlined as follows.

Testosterone (often referred to as ‘T’ in the transgender community) is the key drug for masculisation:¹²

• First line: injected intramuscularly (eg Sustanon), typically 250mg every 2-4 weeks. Dose and frequency are titrated, and blood levels monitored, aiming to match average male blood testosterone levels, with the trough level on the day of injection and the peak a week later.
• Second line: topical testosterone gel (eg Testogel, Tostran, Testavan), applied daily with dose titrated to reach a middle-range adult male blood plasma level, measured 4-6 hours after application.
• Third line: depot testosterone undecanoate injection 1000mg (eg Nebido) loading up through six weekly injections to once every 12 weeks.

Testosterone will usually suppress menstruation, but if not, progestins and GnRH analogues can be used to change ovarian activity.

• progestins – medroxyprogesterone acetate 10mg 2-3 times daily
• GnRH analogues – triptorelin pamoate 11.25mg IM (eg Decapeptyl SR); or gosarelin 10.8mg sub-cutaneously (eg Zoladex); or leuprorelin 11.25mg IM (eg Prostrap) every 12 weeks with the possibility of modifying the dose pro rata for shorter or longer periods between injections; or nafarelin 200-400mcg nasal spray (eg Synarel) twice daily.

Testosterone can be used long term, but progestins and GnHR analogues will be discontinued at the point of genital surgery or ovary removal (oophorectomy).