01/05/2026
Progesterone is often talked about as if it’s automatically protective.
Sometimes it is. Sometimes it isn’t.
Its effect depends on where it’s acting, which receptors are dominant, and what else is happening hormonally at the same time. In certain contexts, progesterone supports stability and differentiation. In others, it can quietly support growth — especially when estrogen signaling is already active.
This is also why “progesterone” and “progestins” shouldn’t be treated as interchangeable. They don’t behave the same way in the body.
Simple labels make hormone decisions feel easier.
They rarely make them safer.