Methods, compositions and kits for treating or ameliorating the following disorders, in male, with help of prolactin are disclosed: a) erectile dysfunction (ED), also from aging, of pituitary/hypothalamic origin； b) premature ejaculation (PE), of pituitary/hypothalamic origin. Said methods, compositions and kits comprise prolactin, variants, analogs, agonists and functional fragments of prolactin, also in combination with conventional therapies and drugs (eg testosterone/androgens and/or gonadotropins).
