Glycine & Core Body Temperature

The Temperature Trigger

For the body to initiate sleep, core body temperature must drop by approximately 1°C. This signals the hypothalamus to switch from "wake" to "rest." Insomniacs often have a delayed thermal drop.

Mechanism: Peripheral Vasodilation

Glycine acts on NMDA receptors in the suprachiasmatic nucleus (SCN), but its primary sleep mechanic is thermal. It triggers peripheral vasodilation—opening up the blood vessels in the hands and feet. This draws heat away from the core and releases it through the skin, rapidly dropping core temperature and inducing sleep onset.