Sleep and cortisol
Why you wake at 3am, and what is actually happening to your cortisol.
It is the single most common thing women describe in clinic. It is not in your head, and it is not the wine.
Davina Hearne. Naturopath. 12 min read. May 2026.
You fall asleep without trouble. Then, at almost exactly the same time each night, you are awake. Not drowsy-awake. Wide awake, heart going, mind switched on as if it were the middle of the afternoon.
If this is you, the first thing to know is plain: this is a recognised physiological pattern, and it has a mechanism. Naming it is the beginning of changing it.
What is happening to your cortisol
Cortisol is meant to follow a curve. Lowest around midnight, climbing through the early hours, peaking shortly after you wake. In the perimenopausal transition, falling progesterone removes one of the brakes on that curve.
Progesterone is the calming hormone. When it falls, the nervous system loses its most reliable evening sedative.
This is why the wake-up feels physical rather than mental. You are not lying awake because you are worried. Your body has run an alerting program at the wrong hour, and the worry arrives afterward to fill the space.
The clinical dose
Where Davina uses magnesium for this pattern, she uses magnesium glycinate, 300-400mg of elemental magnesium, taken in the evening. The glycinate form matters.
Three things to change this week
Light first, within thirty minutes of waking. It anchors the cortisol curve to the correct hour.
Protein at breakfast, thirty grams. Blood-sugar stability through the day reduces overnight adrenaline surges.
Magnesium glycinate in the evening. Give it two to three weeks before you judge it.
This article is educational and is not a substitute for individual medical advice. Always speak to your healthcare provider about your symptoms.