31/01/2026
Progesterone and progestin are often treated as interchangeable, but clinically they are not the same — especially when it comes to fertility and PMS.
Progesterone is a naturally occurring hormone produced after ovulation. Adequate progesterone is essential for a healthy luteal phase, implantation, and pregnancy maintenance. It also helps counterbalance estrogen, which is why low progesterone is commonly associated with PMS symptoms such as anxiety, irritability, sleep disturbance, breast tenderness, and cycle irregularity.
Progesterone also has calming neurological effects through GABA-A receptor activity, supporting mood regulation and sleep quality during the luteal phase.
Progestins, on the other hand, are synthetic compounds designed to bind progesterone receptors. They do not convert into progesterone and do not replicate all of its physiological actions. Many progestins suppress ovulation, which means endogenous progesterone production is reduced, making them unsuitable for fertility support and potentially mismatched for PMS rooted in low progesterone.
When addressing fertility or PMS, the type of hormone matters — not just the name.
