Magnesium Glycinate: The Supplement That Fixes Your Sleep
More than 70% of growth hormone is released during deep sleep. Magnesium glycinate improves sleep quality, reduces cortisol, and costs under €0.30/day.
Why Most Athletes Are Magnesium Deficient
Magnesium is excreted in sweat at roughly 4–8 mg per litre. A hard 90-minute training session can result in 500–800 mg of sweat output — depleting 2–4 mg of magnesium. RDA is 400–420 mg for men, 310–320 mg for women. Combined with chronically low dietary intake (processed foods are stripped of magnesium), most serious athletes are running at a significant deficit without knowing it. Serum magnesium tests miss intracellular deficiency — RBC magnesium is a far better marker.
Magnesium and Sleep Architecture
Magnesium activates GABA receptors — the same receptors targeted by sleep medications like benzodiazepines, but without dependency or next-day grogginess. It also suppresses the hypothalamic-pituitary-adrenal (HPA) axis, reducing evening cortisol. Studies in older adults with poor sleep found that 500 mg magnesium supplementation significantly increased sleep time, sleep efficiency, and serum melatonin, while reducing serum cortisol.
Why Glycinate Form Is Best
Magnesium oxide has less than 4% bioavailability and causes loose stools. Magnesium citrate is better (~16%) but has a laxative effect at higher doses. Magnesium glycinate (chelated with glycine) achieves 80%+ absorption, is gentle on the gut, and glycine itself has independent sleep-promoting properties — it lowers core body temperature, which is the primary physiological cue for sleep onset. This makes glycinate the clear form of choice for athletes.
Protocol
Take 300–400 mg elemental magnesium (as glycinate) 30–60 minutes before bed. This equates to roughly 2,000–2,700 mg of magnesium glycinate by weight. Expect improved sleep depth within 3–5 days, measurable recovery gains within 2–3 weeks. Safe for indefinite use — the body excretes excess magnesium efficiently through the kidneys (do not supplement if you have kidney disease).
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Written by
Sofia Brenner
Certified Strength & Conditioning Coach