https://www.lipophilic-platinum.com/2016/11/21/in-premenopausal-women-blood-was-taken-between-2-and-5-days-after-onset-of-menstruation-in-men-no-significant-associations-were-found-between-serotonin-and-any-of-the-bone-parameters-all-p-0-05-3/