Peat Archive

Progesterone holds a special place in Ray Peat's work — it was the focus of his PhD research in the late 1960s and remained central to his thinking throughout his career. Peat viewed progesterone not merely as a reproductive hormone but as a fundamental protective substance produced by the brain, adrenal glands, and other tissues. He emphasized that progesterone opposes estrogen at virtually every level and supports the body's ability to use oxygen efficiently.

Peat started his work with progesterone in 1968 and was one of the earliest advocates for its therapeutic use. He argued that progesterone deficiency — relative to estrogen — underlies many common health problems including PMS, migraines, epilepsy, infertility, and cancer. He advocated for natural (bioidentical) progesterone, typically dissolved in vitamin E, applied topically or taken orally, and warned against synthetic progestins which have opposite effects.