Kisspeptin

An endogenous peptide sitting at the top of the reproductive axis. Kisspeptin activates KISS1 receptors on GnRH neurons in the hypothalamus, triggering the full cascade: GnRH fires LH and FSH, which drive testosterone production. Think of it as the master switch one level above gonadorelin. The appeal for recovery is that restarting from the very top might produce a more physiologic axis restart than injecting hCG or running a SERM. The fertility researchers are building real data, especially for IVF triggers and hypothalamic amenorrhea. The community running it subcutaneously for axis recovery is extrapolating from that work.

Real human data exists, mostly in fertility, IVF, and hypothalamic amenorrhea. The two findings that shape how people think about kisspeptin for recovery are the sustained gonadotropin response and the tachyphylaxis ceiling:

The community runs subcutaneous kisspeptin-10 at 100 to 200 mcg, once or twice daily. No study has tested timing, and there is no evidence for a best time of day. The science strongly suggests that pulsing beats continuous dosing: tachyphylaxis flattened the LH response within two weeks of twice-daily use in the amenorrhea study, so scheduled breaks or alternating days make more sense than hammering it daily.

The honest protocol note: nobody has proven this works for PCT recovery. The proven restart is a SERM, often with hCG on board, and that protocol has decades of evidence behind it. Kisspeptin is a frontier option for people who want to try the physiologic approach. Some TRT clinics pair it with gonadorelin, though kisspeptin’s only route to the pituitary is via GnRH neurons, so stacking it with synthetic GnRH is extra signal at the same receptor, not a second level. No trial has tested the combination against either alone.

The safety profile in existing studies is clean, but the studies are short and small: