Progesterone

Low progesterone is the most common hormonal issue for women, especially in the luteal phase, and is frequently implicated in problems like irregular cycles, PMS, infertility, and early pregnancy loss.

Progesterone also supports thyroid function by enhancing conversion of T4 to T3 and improving tissue sensitivity to thyroid hormone, so when progesterone is low, effective thyroid signaling drops and metabolic rate often falls, showing up as fatigue, cold intolerance, weight gain, and sluggish metabolism.