This article was reviewed by Julia Switzer, MD, FACOG. If you’re entering perimenopause or menopause, you’ve probably heard about hormone replacement therapy (HRT) — and you might be wondering about ...

Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid ...

While you read this article, your body is busy at work: Chemicals are being secreted from glands, organs, and tissues, sending messages that direct your body to react in certain ways. These chemicals, ...