Progestin vs. Progesterone
Progestin vs. Progesterone names a clinically significant distinction between two pharmacologically different types of compounds used in reproductive medicine. Progestins are synthetic molecules designed to produce progesterone-like effects on the endometrium. They are the active ingredients in most hormonal contraceptives and many hormone therapy formulations. Because progestins differ structurally from natural progesterone, they bind not only progesterone receptors but also androgen, glucocorticoid, and mineralocorticoid receptors, producing off-target effects that include mood changes, libido reduction, and metabolic alterations.
Bioidentical (isomolecular) progesterone shares the same molecular structure as endogenous progesterone. Its receptor binding profile is narrower than most synthetic progestins, limiting off-target activity. In Restorative Reproductive Medicine, isomolecular progesterone is the preferred agent for luteal support and pregnancy maintenance. The clinical rationale rests on the distinct safety and efficacy profiles established for each compound class, not on interchangeability.
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.