Peat Archive

Ray Peat's views on estrogen are among his most contrarian and consequential. He argued that estrogen, rather than being simply a 'female hormone,' is fundamentally a stress hormone that promotes water retention, inflammation, cell proliferation, and metabolic suppression. He saw the medical establishment's promotion of estrogen replacement therapy as one of the great medical scandals, driven by pharmaceutical profits rather than evidence.

Peat traced a long history of research showing estrogen's role in promoting cancer, blood clots, autoimmune conditions, and mood disorders. He noted that estrogen rises with age in both men and women, and that this rise — not decline — is associated with the diseases of aging. He emphasized that estrogen and progesterone have fundamentally opposing actions: estrogen promotes excitation, water retention, and cell proliferation, while progesterone promotes stability, differentiation, and metabolic efficiency.