Kisspeptin-10

Kisspeptin is the product of the KISS1 gene acting on the receptor KISS1R (formerly GPR54). It sits upstream of the hypothalamic-pituitary-gonadal axis: it is the trigger for pulsatile GnRH release from the hypothalamus, and therefore for LH and FSH from the pituitary and testosterone or oestradiol downstream. The pathway was found because loss-of-function KISS1R mutations cause hypogonadotropic hypogonadism. That position upstream is the whole point of the compound and also the reason to be careful with it - it does not act locally, it moves an entire endocrine axis.

Unusually for this dataset, the human data is real and well controlled. Research groups, notably Dhillo and colleagues at Imperial College London, have given kisspeptin-10 and the longer kisspeptin-54 to healthy men and women by intravenous bolus, intravenous infusion and subcutaneous injection and measured the LH response directly with timed blood draws; separate fMRI work has examined limbic responses to sexual and emotional stimuli.

A bolus of roughly 0.3 nmol/kg of kisspeptin-10 - about 25 to 30 mcg for a 70 kg adult - raises LH within tens of minutes, and that is where the 25 mcg floor here comes from. The typical 50 mcg figure sits just above that research bolus. The 200 mcg ceiling reflects the upper end of what grey-market users report, not a dose with controlled support; nothing above the research bolus has been shown to give a better response.

Two caveats matter more than the number. First, the response desensitises: continuous or very frequent exposure downregulates the GnRH response instead of amplifying it, which is why intermittent dosing is the rational pattern and why more is not better. The every-other-day default here reflects that, not a trial protocol. Second, all of the human work is acute. There is no approved kisspeptin product anywhere, no long-term safety data, and nothing published on what repeated self-administration does to the axis over months, which is why no cycle length is given.

Clearance is fast - kisspeptin-10 is cleared within a few minutes and kisspeptin-54 in roughly half an hour - so no hourly half-life is listed. Sensitivity differs between men and women and, in women, across the menstrual cycle. Note also that a 10 mg vial is far larger than a single dose: even reconstituted in 5 mL, 50 mcg is about 2.5 units on a U-100 syringe, so accurate measurement needs care or a further dilution.