PT-141 (bremelanotide) acts directly on desire centres in the brain and works within hours. Its injection form was approved in the US in 2019 for low sexual desire in premenopausal women. Kisspeptin works one step earlier: it signals the brain to release the hormones that drive testosterone and fertility, and small studies show it also strengthens sexual and emotional brain responses. PT-141 is taken when needed, while Kisspeptin is usually part of a hormone plan. Low desire often has a medical cause, so a physician should check hormones, medicines and mood first.