For people assigned male at birth transitioning to a feminine gender identity, oestrogens are the principal drugs used for feminisation.¹²

Oral estradiol valerate or estradiol hemihydrate 2mg daily is the first line recommendation, with doses titrated by 2mg every 3 months if necessary to achieve a target plasma level of 400-600 picomoles per litre. Typically, the maintenance dose is 2mg to 8mg per day.

Second line options are topical oestrogen gel (eg Sandrena) between 0.5mg to 5mg per day adjusted every three months, or estradiol patches (50mcg to 200mcg twice a week). In exceptional circumstances, oral ethinylestradiol 50mcg to 150mcg daily may be a third-line option.

If plasma testosterone levels are not suppressed sufficiently, a GnHR analogue may be added at the same doses as used for transitioning to a masculine identity.¹²

Gonadorelin analogues initially cause stimulation, but with continued use will down-regulate gonadotrophin-releasing hormone receptors. This reduces the release of gonadotrophins (follicle stimulating hormone and luteinising hormone) inhibiting androgen and oestrogen production.¹⁷

The antiandrogen cyproterone acetate may be added to limit any testosterone flare when initiating GnHR analogues. This is typically a dose of 50mg daily for the first 14 days of GnHR treatment but should be avoided in liver disease.¹²

To suppress hirsutism (hair growth where not desired), cyproterone acetate 50-150mg daily or finasteride 5mg daily may be used.

While oestrogen treatment will be ongoing, GnHr analogues will be discontinued after gender reassignment surgery or orchiectomy (removal of the testes).¹²