Progestins
Progestins are synthetic compounds that bind progesterone receptors and produce effects similar to endogenous progesterone, including endometrial transformation, suppression of uterine contractility, and feedback on the hypothalamic-pituitary-gonadal axis. They differ from bioidentical (micronized, body-identical) progesterone in chemical structure, receptor binding profile, metabolism, and side-effect spectrum.
Structurally, progestins fall into two main lineages: testosterone-derived agents (norethindrone, levonorgestrel, desogestrel) and progesterone-derived agents (medroxyprogesterone acetate). Drospirenone derives from the spirolactone series. Many progestins exhibit androgenic, antiandrogenic, glucocorticoid, or mineralocorticoid activity in addition to progestational effects, producing off-target consequences that vary by compound. Progestins serve as the active progestational ingredient in combined oral contraceptives, progestin-only pills, hormonal intrauterine devices, contraceptive implants, depot medroxyprogesterone acetate, and some menopausal hormone therapy regimens.
Restorative Reproductive Medicine draws a sharp clinical and ethical distinction between progestins and bioidentical progesterone, which Hilgers frames as the difference between isomolecular hormones and heteromolecular artimones. For luteal phase defect, threatened miscarriage, and premenstrual symptoms, RRM clinicians use bioidentical progesterone (typically intramuscular, vaginal, or oral micronized formulations) rather than synthetic progestins, on the basis of differing receptor pharmacology, breast cancer risk profiles, and pregnancy safety data.
This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.