# Magnesium glycinate: benefits, dose and how it compares Source: https://magnesiumguide.uk/forms/magnesium-glycinate/ Author: Nell Hartley ยท Updated 2026-11-04 **Short answer:** Magnesium glycinate is magnesium bound to the amino acid glycine. It is gentle on the gut and appears well absorbed, which makes it a good choice for people who get loose stools from other forms. A 2025 placebo-controlled trial found it modestly improved insomnia scores. Claims that it is uniquely calming are not proven. ## What is magnesium glycinate? It is a chelate: one magnesium atom held between two molecules of glycine, the smallest amino acid. Because glycine is a light molecule, magnesium still makes up about 14% of the weight. So a 500 mg capsule of magnesium glycinate gives roughly 70 mg of magnesium, and many products need two to four capsules for a typical dose. ## Is magnesium glycinate better absorbed? Probably well absorbed, but the evidence is thin. A 2003 trial found an amino acid chelate (a similar product) was absorbed better than magnesium oxide over 60 days, though not quite as well as citrate. A small 1994 study in people with part of their small bowel removed found glycinate was absorbed about as well as oxide overall, but better in those with the worst absorption, and it caused fewer stomach problems. Researchers think some of it may be absorbed intact, by the same route the gut uses for small proteins. ## What is magnesium glycinate good for? **People who get diarrhoea from magnesium.** This is its clearest advantage. Glycinate is the form least likely to loosen stools at normal doses. **Sleep.** The best trial of magnesium for sleep used bisglycinate. In 2025, 155 German adults with poor sleep took 250 mg of magnesium as bisglycinate or placebo each day. After four weeks, insomnia scores had improved slightly more on magnesium than on placebo. The effect was small, and greatest in people who ate little magnesium. See [magnesium for sleep](/benefits/sleep/). **Anxiety.** It is widely sold as calming, but we found no placebo-controlled trial of magnesium glycinate for anxiety. See [anxiety and stress](/benefits/anxiety-and-stress/). ## What is buffered magnesium glycinate? Some products labelled glycinate are "buffered", meaning magnesium oxide has been mixed in to raise the magnesium per capsule and cut the cost. That's not dishonest if it's declared, but it means you get some of oxide's laxative effect. Look for "fully reacted" or "bisglycinate chelate" on the label, or check the ingredient list for magnesium oxide. The [types of magnesium compared](/forms/) table shows how the forms differ. ## Is glycinate or citrate better? | | Glycinate | [Citrate](/forms/magnesium-citrate/) | | --- | --- | --- | | Magnesium by weight | About 14% | About 16% | | Absorption | Good | Good, best studied | | Gut | Gentlest | Can loosen stools | | Cost | Usually higher | Usually lower | | Best for | Sensitive stomachs, evening doses | General topping up, constipation-prone people | ## How should you take magnesium glycinate? - Check the elemental magnesium per serving on the label. Our [buying guide](/buying-guide/) has a calculator for the real cost per 100 mg. - Start with 100 to 200 mg of magnesium a day and stay at or below 400 mg from supplements unless a doctor advises more. See [dosage and timing](/how-to-take/dosage-and-timing/). - Take it with food, and keep it two to four hours apart from medicines it interferes with, such as some antibiotics and osteoporosis tablets. See [medicines it affects](/safety/drug-interactions/). - Don't take it if you have kidney disease unless your doctor recommends it. ## Frequently asked questions ### Is magnesium glycinate the same as bisglycinate? In practice, yes. Bisglycinate means each magnesium atom is bound to two glycine molecules, which is what most products labelled glycinate contain. Some cheaper products are a mix with magnesium oxide, sold as buffered glycinate; check the ingredients list. ### How much magnesium glycinate should I take? Go by the elemental magnesium on the label, not the glycinate weight. Most adults who need a supplement take 100 to 300 mg of elemental magnesium a day, and the NHS says up to 400 mg from supplements is unlikely to cause harm. That is roughly 700 mg to 2.8 g of magnesium glycinate. ### Should I take magnesium glycinate at night? If you are taking it for sleep, the trials gave magnesium in the evening. Otherwise, time of day matters little; taking it with food makes stomach upset less likely. ### Does glycine in magnesium glycinate help sleep? Glycine on its own has been studied for sleep at about 3 g before bed, with small effects on how rested people felt. A 250 mg dose of magnesium as bisglycinate carries about 1.5 g of glycine, so any extra effect from the glycine is likely to be small. ## References 1. [Schuster J et al. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep, 2025.](https://pubmed.ncbi.nlm.nih.gov/40918053/) 2. [Schuette SA et al. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. Journal of Parenteral and Enteral Nutrition, 1994.](https://pubmed.ncbi.nlm.nih.gov/7815675/) 3. [Walker AF et al. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research, 2003.](https://pubmed.ncbi.nlm.nih.gov/14596323/) 4. [Bannai M et al. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in Neurology, 2012.](https://pubmed.ncbi.nlm.nih.gov/22529837/) 5. [NHS. Vitamins and minerals: others (magnesium).](https://www.nhs.uk/conditions/vitamins-and-minerals/others/)