I was 17 when I was first prescribed the pill. The appointment lasted eight minutes. I was not told about SHBG. I was not told which synthetic progestin I was being given or what else it binds beyond the progesterone receptor. I was not told about the cortisol profile changes, the depression association documented in over a million women, or the preference reversal. The information existed. It was published. It was not passed on.

Everyone is told to lower their cortisol. Nobody explains what cortisol actually does — or that in the female body, it follows a measurably different pattern across the menstrual cycle, interacts with estrogen through two opposing receptor pathways, and was excluded from stress research for decades because its variability was considered a confound. That variability is the biology.

Intermittent fasting can improve insulin sensitivity, PCOS symptoms, and metabolic health, but for women, the story is more nuanced than the internet makes it sound.

This post breaks down what IF actually does to cortisol, thyroid function, and reproductive hormones, and how to approach it in a way that works with female biology.