Medicines
Given repeatedly, a GnRH agonist such as buserelin first stimulates and then switches off the pituitary's own hormone release, which is the basis of down-regulation. Given once at a precise time, it can prompt the body's own LH surge and be used as a trigger. Your clinic decides which use applies to your cycle.
Related United Kingdom guides
Last reviewed: 23 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.