> Estrogen is a stress and crisis hormone, so there’s a steady upward tendency in its effect with age, which is interrupted during the fertile years by [[progesterone]]. [[Progesterone]] decline usually starts around age 40 because of things interfering with [[thyroid]] function. Declining liver function and increasing pituitary activity influence the way problems develop. Oxygen tension is normally low in bone marrow, and stimulates constant cell proliferation, but when estrogen’s oxygen-wasting effect is added, it changes the balance of cell growth; its worst effect is to stimulate fibroblasts and collagen production in the marrow, displacing the red and white cells. Estrogen shifts cells from oxidative production of carbon dioxide to the glycolytic formation of lactic acid, tending to prevent normal differentiation of cell function. The effects of estrogen include the leakage of the lactic acid-forming enzyme LDH into the serum, and the increase of copper in the serum, and these are recognized as signs of CLL, but the genetic-clonal ideology of [[cancer]] prevents recognition of the metabolic pattern. Estrogen causes relative hyperventilation, reinforcing the cellular changes. CLL seems to be less common in people adapted to high [[altitude]], where lactic acid formation is inhibited. [(Reference)](https://archive.ph/o/OJZkW/https://raypeatforum.com/community/threads/ray-peat-email-advice-depository.1035/page-14%23post-175620)