Magnesium Glycinate vs. Citrate: Which One Actually Fixes Sleep

Walk into any pharmacy and you'll find six kinds of magnesium on the shelf. They are not interchangeable. Buy the wrong one and you'll spend $12, sleep no better, and visit the bathroom a lot. Here's the honest breakdown of the three forms you'll actually see.

Magnesium glycinate — the sleep form

Magnesium bonded to glycine, an amino acid that is itself mildly calming. Absorption is high (roughly 40%), it doesn't cause diarrhea at normal doses, and the glycine adds a small but real sedative effect. This is the form to take for sleep, palpitations, or anxiety. 300–400 mg 30–45 minutes before bed is the standard dose.

Magnesium citrate — the bowel form

Magnesium bonded to citric acid. Absorption is decent (~25%), but citrate pulls water into the bowel — which is why it's the active ingredient in most gentle laxatives. At 200 mg you might feel calm; at 400 mg you'll likely feel something else. If you're constipated on keto, citrate is useful. If you want to sleep, it isn't.

Magnesium oxide — the cheap useless form

The cheapest form on the shelf and the reason "magnesium didn't work for me" is such a common complaint. Absorption is roughly 4%. Most of what you swallow passes straight through. If your bottle says magnesium oxide and nothing else, replace it.

Others you'll see (short version)

• Threonate — expensive, marketed for brain effects. Fine, but glycinate does the sleep job at a third of the price.
• Malate — good for daytime energy, not sedating.
• Chloride (topical spray) — absorbs some, useful for leg cramps applied directly. Not a full replacement.

Bottom line

For 3am wakeups, cramps, palpitations and low-carb sleep problems: magnesium glycinate, 300–400 mg, 30–45 minutes before bed. That single swap fixes more sleep complaints than any other supplement change I know of.