Progesterone is a hormone that not only regulates your monthly period, but also prepares your body for pregnancy and helps to protect your uterus during menopause.

What Is Progesterone?

Like estrogen, progesterone is naturally produced by your body, mainly in your ovaries. Together with estrogen it helps regulate the uterine lining, thickening it when an egg has been released and shedding it if the egg isn’t fertilized. Progesterone appears in products you’re probably familiar with like hormonal birth control pills, vaginal rings, skin patches, birth control implants, and hormonal IUDs.

What Is Progestin?

Progestin is a synthetic version of progesterone. It’s derived in a laboratory from plants like soy and yams. Progestin has similar effects to progesterone and stays in your system longer. This allows progestin to provide longer lasting effects per dose.

What’s the relationship between Estrogen and Progesterone?

You’ve probably seen that some hormonal birth control methods use a combination of estrogen and progestin. You’ll also see this in some hormonal menopause treatments. Progestin/progesterone is often prescribed with estrogen as a precautionary measure to limit the growth of uterine tissue.

This is because estrogen promotes the continuous growth of cells in the uterus. When you’re menstruating, those cells are shed every month through your period. But once menstruation stops (through menopause or birth control), if you take estrogen alone the cells can build up, thickening your uterus and leading to abnormal growths, which can then lead to uterine cancers. Progestin helps prevent this by keeping the uterine lining thin.

How Does Progesterone Affect the Rest of the Body?

While progesterone is mainly recognized for its role in fertility and menstruation, it should not be overlooked when it comes to your bones and sleep. Paired with estradiol (a form of estrogen), progesterone can help reduce bone loss and prevent fractures. Progesterone is also known to have a mild sedative effect, so when your estrogen and progesterone levels drop during menopause, it may be part of the reason you’re having sleep troubles. Not only does progesterone help with your bones and sleep, it’s shown to support skin firmness and elasticity.