Progesterone is a hormone released by ovaries. It’s made from cholesterol, which might seem odd. It’s a key component in birth-control pills and in hormone replacement therapy (where it lowers the cancer risk that comes with just taking straight estrogen).
This molecule here, 20α-Dihydroprogesterone (also known as 20α-hydroxyprogesterone), comes from progesterone in the body and can be converted back into progesterone. Medically, it can be used to treat brain and nerve problems because it helps keep the myelin sheaths around our neurons healthy – basically, if nerves are wires, the myelin is the insulation around it. It’s also related to a bunch of drugs used to make menstruation easier, because it helps the uterus shed its lining.
In this illustration, the red bits are oxygen (not red in real life), the white bits are hydrogen (not white in real life), and the black bits are carbon (sometimes black in real life). I can’t help but think it looks a little like an unripe mulberry.