Last edited 05/2020 and last reviewed 05/2020

Oestradiol is the main endogenous female sex steroid which can be produced from:

  • testosterone
  • oestrone

Its synthetic forms include:

  • ethinyloestradiol, used in the combined oral contraceptive pill
  • oestradiol valerate, used within forms of hormone replacement therapy

If the correct aromatase enzymes are present, oestradiol can be interconverted to testosterone. The reverse reaction often occurs in obese males due to the abundance of aromatase in peripheral adipose tissue. Consequently, there may be evidence of feminization.

Oestradiol is metabolized to oestriol for excretion.