Progesterone is a hormone produced by the ovaries, along with oestrogen. These hormones help to regulate several functions of your body; progesterone in particular is essential for fertility and ensuring a healthy pregnancy. The hormone also helps to regulate monthly menstrual cycles if you're not pregnant.
Perhaps most importantly it helps to protect the brain and is evident in the thymus gland which is important to maintain a healthy immune system. Progesterone also helps to prevent against women suffering from osteoporosis.!