Know2eat

Magnesium glycinate (bisglycinate)

Minerals

What magnesium glycinate (bisglycinate) may help with

Ranked by how strong the human evidence is — best supported first.

Best supportedSleep qualityLimited evidence· 2 sources

Then, in order

About Magnesium glycinate (bisglycinate)

Magnesium chelated to two molecules of the amino acid glycine, supplying roughly 14% elemental magnesium. It is the form most often recommended for people who cannot tolerate other magnesium salts.

Magnesium glycinate has an excellent reputation and a thin evidence file. The claim that it is gentler on the bowel is mechanistically reasonable — amino acid chelates are thought to be absorbed partly through peptide transport pathways rather than remaining osmotically active in the lumen — and it matches widespread user experience, but head-to-head trials comparing gastrointestinal tolerance between magnesium salts are almost non-existent. The further claims, that glycine adds a calming or sleep-promoting effect of its own, rest on separate small studies of glycine at doses of about 3 g, far more glycine than a magnesium glycinate capsule provides.

Sold as
Capsule, Tablet, Powder, Combination with magnesium malate or citrate
Standardised to
Fully reacted chelates are distinct from "buffered" products blended with magnesium oxide — a product without this marker may not resemble what was studied.
Also known as
Magnesium bisglycinate, Chelated magnesium, Magnesium diglycinate

Regulation: Subject to the same 350 mg/day supplemental magnesium upper limit. Sold with no pre-market efficacy review, and "chelated" is not a regulated term — some products labelled bisglycinate are buffered with magnesium oxide, which changes both the elemental content and the tolerability.

What the research used

The amounts, forms and durations published trials of Magnesium glycinate (bisglycinate) actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

  • Studied for Typical retail supplement

    100–400 mg

    Not enough

    Elemental magnesium, daily

    Because the salt is only about 14% magnesium, capsules are large and often supply less elemental magnesium than the label suggests at a glance. Buffered products blended with oxide are common and are not the same thing.

  • Studied for Absorption studies

    300 mg

    Limited

    Amino acid chelate versus inorganic salt

    Small studies suggest chelated forms are absorbed better than oxide. Direct comparisons between glycinate and citrate are scarce, and no trial has compared clinical outcomes between magnesium forms.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

  • Evening

    Not enough

    Almost universally sold as a bedtime supplement. The convention rests on the belief that magnesium and glycine are both calming; no trial has compared evening with morning dosing.

    Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

The evidence in depth

Best supported: Limited

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.

Sleep quality

Sleep
Limited evidence

Evidence for magnesium and sleep is weak generally, and no trial has tested the glycinate form specifically. Separate small studies of glycine at around 3 g before bed report improved subjective sleep quality, but a typical magnesium glycinate dose supplies well under that.

Limited evidence. Early human work, or mostly lab and animal research.

View the 2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Stress and anxiety

Mental Wellbeing
Limited evidence

Some trials of magnesium supplementation report modest reductions in anxiety scores, mainly in people with low magnesium status or raised anxiety at baseline. Reviews describe the evidence as low quality, and none of it is specific to the glycinate form.

Limited evidence. Early human work, or mostly lab and animal research.

View the 4 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Digestive comfort

Gut & Digestive Health
Not enough evidence

The central selling point — that it causes less diarrhoea than other magnesium salts — is plausible and essentially untested in controlled comparisons. It rests on absorption reasoning and user reports.

Not enough evidence. Not enough human research to say anything useful yet.

View the 2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

  • Too much

    Hypermagnesaemia risk in kidney disease

    Better tolerability does not change the excretion route. In moderate to severe kidney impairment, any magnesium supplement can accumulate to dangerous levels.

  • Interaction

    Same absorption interference with medicines

    Interacts withTetracyclines, fluoroquinolones, bisphosphonates, levothyroxine

    Magnesium in any form reduces absorption of tetracyclines, fluoroquinolones, bisphosphonates and levothyroxine. Separate doses by two to four hours.

  • Worth knowing

    "Buffered" products are partly magnesium oxide

    Some products labelled magnesium bisglycinate are blends with magnesium oxide, which raises the elemental content on the label while reintroducing the laxative effect the buyer was trying to avoid. Fully reacted chelates state so explicitly.

  • Worth knowing

    The upper limit still applies

    The 350 mg/day supplemental limit covers all magnesium forms. Combining a magnesium supplement with a magnesium-containing antacid or laxative is an easy way to exceed it without noticing.

Evidence ratings on this page: 2 limited evidence, 1 not enough evidence.

Supplements are sold in the US without pre-market review of efficacy or safety. Nothing on this page is a recommendation to take Magnesium glycinate (bisglycinate), or a dose to follow.