Sleep, stress and recovery

Magnesium glycinate

Also called: magnesium bisglycinate, chelated magnesium

Magnesium glycinate is a chelated form where each magnesium atom is bound to two glycine amino acids. It is well-absorbed, gentle on the gut (does not cause the loose stools magnesium oxide or citrate can), and the form most often used for sleep, muscle cramps, anxiety and PMS. Typical dose is 200 to 400 mg of elemental magnesium taken in the evening.

Why glycinate specifically

  • Bioavailability is reasonable but not exceptional, Schuette 1994 measured magnesium diglycinate absorption around 23.5%. The 80% figure that circulates online is a marketing claim with no published evidence.
  • Glycine itself has a calming effect on the brain (small but measurable).
  • Does not pull water into the gut like citrate or oxide, so no laxative effect.
  • Well-tolerated even at higher doses.
  • More expensive than oxide, similar price to citrate.

What it actually helps

  • Sleep onset and quality: modest evidence (low-quality trials) at 200 to 400 mg before bed.
  • Muscle cramps and twitches.
  • PMS symptoms in the luteal phase.
  • Migraines (some evidence at 400 mg daily as prophylaxis).
  • Anxiety and stress (mixed evidence; effect probably small).
  • Constipation: NOT this form. Use citrate or oxide if constipation is the goal.

Forms of magnesium and what they're for

  • Glycinate: sleep, cramps, anxiety. Gentle on gut.
  • Citrate: constipation, mild laxative effect.
  • Oxide: cheap, poorly absorbed, mostly used as a laxative or antacid.
  • Threonate: small evidence for memory and cognition; expensive.
  • Malate: muscle pain and fatigue (some evidence in fibromyalgia).
  • Sulfate: Epsom salts; topical for muscle aches, oral as a strong laxative.

Dosing

  1. UK adult RDA from food: 270 to 300 mg/day. Most people get 200 to 250 from diet.
  2. Supplement dose: 200 to 400 mg of ELEMENTAL magnesium. Watch labels carefully, 1000 mg of magnesium glycinate yields about 140 mg of elemental magnesium.
  3. Take in the evening, with food, for sleep benefit.
  4. Build up gradually over a week to avoid stomach upset.
  5. Upper limit (UK EVM safe upper level): 400 mg supplemental per day.

Foods rich in magnesium

  • Pumpkin seeds (around 550 to 590 mg per 100 g for dried kernels).
  • Spinach (79 mg per 100 g).
  • Almonds (270 mg per 100 g).
  • Dark chocolate 70%+ (228 mg per 100 g).
  • Black beans (70 mg per 100 g cooked).
  • Avocado (29 mg per 100 g).

Common questions

Should I take it every night?
Reasonable for chronic poor sleep, regular muscle cramps or PMS in the luteal phase. Otherwise occasional use is fine. There is no addiction risk and no rebound on stopping.
Will it interact with other medications?
Magnesium can reduce absorption of some antibiotics (tetracyclines, quinolones), bisphosphonates, and thyroid medication. Take at least 2 hours apart, and at least 4 hours apart from thyroid medication (levothyroxine). Check with a pharmacist if on multiple medications.
Is more better?
No. Above 400 mg/day supplemental, you start seeing diarrhoea even with glycinate. Kidneys excrete excess. Sticking to 200 to 400 mg covers most use cases.
Can I get enough from food?
Most people technically can but most do not. UK women average about 238 mg/day from food and men about 302 mg/day, against a 270 to 300 mg target, so many women fall short. Supplementing 200 mg is a low-risk way to top up.

Sources

The Book of Suna is general information, not medical advice. It is not a substitute for talking to a qualified healthcare professional about your own situation.