Mood swings, disrupted sleep, and irregular periods can signal either PMS or the start of perimenopause — and the distinction matters. Here's how to read your hormonal signals by pattern, not just symptom.
Your cycle is driven by four distinct hormonal phases — each shifting estrogen, progesterone, LH, and FSH in ways that directly shape your energy, mood, and focus. Here's the science behind what you feel and why.