Cetrorelix

How it works

Blocks GnRH receptors in the pituitary, halting the LH surge that would release eggs before IVF retrieval. Nobody leaves early.

What it's made of

10 amino acids: GnRH with five pieces swapped, several for D-amino acids that enzymes do not recognize. It no longer activates the pituitary receptor: it blocks it.

What it's for

Prescribed for

Preventing the premature LH surge, which would cause ovulation too early, in women undergoing ovarian stimulation for assisted reproduction.