Progesterone Levels Peak at the Start of the Luteal Phase Progesterone is a major reproductive hormone, and though it’s usually talked about in relation to women, men produce it in small amounts, too.e60dc2a1-f33c-4a05-9b50-8e3e8e597629c2d63a0f-160f-4d1d-809f-db0bd5293534 In women, progesterone levels naturally fluctuate over the course of the menstrual cycle. “We’re not walking around in the same hormonal state all month,” says Thea Gallagher, …