" The other major hormonal player in your cycle is progesterone. It helps to prepare the uterus for implantation with a healthy fertilized egg and supports pregnancy. If no implantation occurs, progesterone levels drop, and another cycle begins. Progesterone receptors are highly concentrated in the brain. Progesterone can support GABA, the brain’s relaxation neurotransmitter; acts to protect your nerve cells; and supports the myelin sheath that covers neurons. I like to think of progesterone as the “feel-good hormone.” It makes you feel calm and peaceful and encourages sleep. It’s like nature’s Valium, but better, because instead of making your brain fuzzy, it sharpens your thinking. It has also been shown to help with brain injuries by reducing inflammation and counteracting damage. It is so much more than a sex hormone. Progesterone increases during pregnancy, which is why many pregnant women often feel great. Some women with hormonal issues, in fact, feel so much better during pregnancy that they will "

― Daniel G. Amen , Unleash the Power of the Female Brain: Supercharging Yours for Better Health, Energy, Mood, Focus, and Sex