GnRH agonist protocol

The long agonist protocol begins with a GnRH agonist, often in the luteal phase of the previous cycle, to down-regulate the pituitary before stimulation starts. It takes longer and involves more injections, but suits some patients — for example where cycle timing needs tight control or where response has been uneven.

Also known as: long protocol, down-regulation protocol, long down-reg

Last reviewed: 10 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.