Kisspeptin is the hormone that controls puberty and the reproductive function.

Among many other functions Kisspeptin acts on the hypothalamus to allow it to release GnRH. It is this GnRH that controls puberty and reproduction.

In people with Kallmann syndrome / CHH they are unable to release GnRH at all or in the correct manner in order to function correctly.

If injected with Kisspeptin people with Kallmann syndrome / CHH will not respond in the same way other people would. This makes Kisspeptin as useful diagnostic tool for Kallmann syndrome / CHH to distinguish it from delayed puberty.