Harry K-P | Shes Not Crazy :
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🧬 Cycle length averages 28 days with a normal range of roughly 21 to 35, and varies month to month within the same woman (Bull et al., 2019, npj Digital Medicine, 600,000+ cycles)
🧬 Estrogen and testosterone fall by roughly 50-85% across the post-ovulatory transition (cycle endocrinology)
🧬 The 125 years is a derivation, not a study. It sets that drop against documented male testosterone decline of roughly 0.4-1% a year (Harman et al., 2001, JCEM). Felt comparison, not a clinical measurement.
🧬 The post-ovulatory drop and premenstrual progesterone withdrawal are two separate events. PMS symptoms cluster in the 3-5 days before menstruation (ACOG)
🧬 Around 400 cycles across a reproductive lifetime. Rounded, not counted.
🧬 Perimenopause typically lasts 4 to 8 years, range extending to 10 or more (Harlow et al., 2012, STRAW +10, JCEM)
2026-08-25 10:53:52