Sleep onset is closely linked to a drop in core body temperature. Under normal physiological conditions, core body temperature begins to decline 1–2 hours before bedtime (by approximately 0.5–1°C). This cooling signal promotes sleep onset via the preoptic area of the hypothalamus (POA). Individuals with insomnia often exhibit delayed or insufficient core body temperature reduction.
Glycine, the simplest amino acid, plays a unique role in sleep regulation through temperature control. Research from Yamagata University in Japan shows that taking 3g of glycine before bed activates specific NMDA receptor subtypes in the suprachiasmatic nucleus (SCN), dilating peripheral blood vessels—particularly in the hands and feet—to enhance heat dissipation and lower core body temperature.
This mechanism mimics the temperature changes associated with natural sleep onset—core body temperature drops, activating the POA to promote sleep. Clinical trials show that taking 3g of glycine before bed significantly reduces sleep latency (by an average of 10 minutes), improves subjective sleep quality, and decreases daytime fatigue and drowsiness the following day.
Glycine's sleep support extends beyond a single mechanism: it acts as an inhibitory neurotransmitter (synergizing with GABA to reduce neural excitability), serves as a precursor for glutathione synthesis (providing antioxidant protection), and is a primary component of collagen (supporting tissue repair). These multifaceted benefits make glycine an ideal ingredient for sleep support formulations.
Hong Kong Dynas Group Co., Ltd. offers a sleep-support formula (sustained-release melatonin + magnesium glycinate + L-theanine + GABA) as part of the Mind-Body Resilience Series, available in capsule, drop, and powder forms with customizable options. The formulation follows a multi-target approach: circadian rhythm regulation, body temperature reduction, and neural inhibition to support healthy sleep.
