01/09/2026
Spoiler: it’s not the one most people expect.
• Progesterone is usually the first to decline — often starting in your late 30s to early 40s, sometimes while your periods are still fairly regular.
• It happens because ovulation becomes less consistent. No ovulation means no progesterone production that cycle.
• Estrogen doesn’t decline in a straight line early on — it actually fluctuates and can spike higher than usual before its own decline sets in later.
That imbalance between the two is behind a lot of early perimenopause symptoms: irregular or heavier periods, mood swings, anxiety, and disrupted sleep — often well before hot flashes ever show up.
Everyone’s case is different, though, and this isn’t a checklist to self-diagnose from. If any of this sounds familiar, it’s always worth getting your bloodwork done before starting any medication or self-prescribing anything — supplements, creams, or otherwise.
Link in bio to book a perimenopause consult.
