Does regular use of melatonin cause prolactin or cortisol to become elevated?

Melatonin & Prolacti: There was one study in perimenopausal women showed that melatonin increases gonadotropins & prolactin levels & lowers fsh (follicular stimulating hormone) levels in 6 out of 7 women in the study.

No studies: I don't know of any studies that show this. The studies on melatonin have generally shown it to be safe. However since melatonin is not under fda jurisdiction, the purity and potency of a given product cannot be assured.