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Magnesium for sleep: glycinate vs threonate vs citrate

Magnesium is the most searched sleep supplement in the US, and the form on the label changes what you get. Here is which form fits which goal, the doses used in trials, and what each costs per month.

By CalcMyPeptide editorial team · Medical review pending · Last reviewed Oct 7, 2026 · Prices checked Oct 7, 2026

Quick answer

For sleep and calm: magnesium bisglycinate (glycinate), 200–350 mg elemental magnesium, 30–60 minutes before bed.
For sleep plus next-day focus: magnesium L-threonate (Magtein), 2 g of the compound (~145 mg elemental magnesium) daily.
For constipation: citrate. For sleep it is a poor pick because the laxative effect arrives first.
Keep supplemental magnesium at or under 350 mg/day unless your clinician says otherwise, and ask first if you have kidney disease.

The question we get most

Someone sees a TikTok about magnesium for sleep, buys the cheapest bottle on the shelf, and spends the next morning in the bathroom. That bottle was magnesium citrate or oxide: useful for constipation, not for a calm night.

The fix is simple once you know the forms. Glycinate is the everyday sleep pick with the best direct trial evidence. L-threonate is the premium, brain-targeted option. Citrate is a laxative first. The rest of this page is the detail behind those three sentences.

The three forms, side by side

Magnesium bisglycinate (glycinate): magnesium bound to glycine. Gentle on the gut, well absorbed, and the form in the best recent sleep trial (250 mg elemental/day for 4 weeks). Cheapest per useful dose.
Magnesium L-threonate (Magtein): magnesium bound to threonate, developed to raise magnesium in the brain. Small trials show better deep/REM sleep scores and cognitive tests. About three times the price of glycinate for less elemental magnesium.
Magnesium citrate: well absorbed but draws water into the gut. Great for constipation; at sleep doses it often means an urgent morning.
Oxide: the cheapest and most common in drugstores, poorly absorbed, mostly a laxative. Skip it for sleep.

How much, and how to read the label

Find “elemental” magnesium. Labels list the magnesium in mg (elemental) and sometimes the compound weight. 2 g of magnesium L-threonate gives only about 145 mg of magnesium; 2 capsules of a bisglycinate often give 200 mg.
Start at 200 mg. Take it 30–60 minutes before bed for two weeks before judging. Most of the trial effects were modest and built over weeks.
Stay under the ceiling. The US upper limit for supplemental magnesium is 350 mg/day for adults. Magnesium from food does not count toward it.
Pick one form. Doubling up (a glycinate plus a threonate plus a magnesium “sleep drink”) is how people overshoot. Choose the form that matches your goal.

Who is most likely to notice a difference

People who eat few leafy greens, nuts, seeds, beans or whole grains.
Older adults: a meta-analysis of trials in older people found modest improvements in time to fall asleep.
People on medicines that lower magnesium, such as long-term proton-pump inhibitors or some diuretics (ask your prescriber before supplementing).
Less likely: people already eating plenty of magnesium-rich food, or whose sleep problem is sleep apnea, hot flashes or a newborn.

Magnesium, by goal

Choose one magnesium. Add L-theanine if a busy mind is the problem. Grades reflect the human trials for each form.

Stack at a glance. Evidence grade: A strong · B moderate · C limited · D preliminary.
Ingredient	Dose	When	Evidence
Magnesium bisglycinate (glycinate)	200–400 mg elemental magnesium	30–60 minutes before bed	B · moderate
Magnesium L-threonate (Magtein)	2 g magnesium L-threonate (~145 mg elemental magnesium)	30–60 minutes before bed (or split morning/evening)	B · moderate
L-theanine	100–400 mg (start at 200 mg)	With the magnesium, 30–60 minutes before bed	B · moderate

01
Magnesium bisglycinate (glycinate)
Evidence B · moderate
200–400 mg elemental magnesium, 30–60 minutes before bed. Supports a calm nervous system and muscle relaxation at night. The foundation: cheap, well studied, gentle on the gut in this form.
What the research shows: A 2025 randomized trial in 155 adults reporting poor sleep found 250 mg/day of elemental magnesium as bisglycinate lowered insomnia-severity scores a little more than placebo at 4 weeks (−3.9 vs −2.3 points). Older trials in older adults point the same way; effects are modest and largest in people who run low. (PMID 40918053, PMID 33865376, PMID 23853635)
- Stay at or under 350 mg/day of supplemental magnesium unless a clinician says otherwise (the US upper limit for supplements); food magnesium does not count toward it.
- Kidney disease: ask first. Magnesium can build up when kidneys clear it poorly.
- Separate from levothyroxine, tetracycline/quinolone antibiotics and bisphosphonates by at least 2–4 hours.
What to look for on the label
Magnesium bisglycinate or glycinate, labelled in mg of elemental magnesium (not compound weight); third-party tested (NSF or USP).
We only name brands we have vetted and work with; a specific pick will appear here once one is approved.
02
Magnesium L-threonate (Magtein)
Evidence B · moderate
2 g magnesium L-threonate (~145 mg elemental magnesium), 30–60 minutes before bed (or split morning/evening). The “brain magnesium”. Pick it when daytime focus and next-day sharpness matter as much as sleep; it costs about three times more than glycinate.
What the research shows: In a 21-day randomized trial of 80 adults aged 35–55 with self-reported sleep problems, 1 g/day of magnesium L-threonate improved Oura-measured deep and REM sleep scores and morning energy versus placebo. Two other randomized trials of Magtein-based products reported cognitive-test improvements in adults. Promising, but all small and short. (PMID 39252819, PMID 26519439, PMID 36558392)
- Counts toward the 350 mg/day upper limit for supplemental magnesium; do not stack a full dose of threonate and glycinate without a clinician.
- Kidney disease: ask first.
- Some people get loose stools or vivid dreams; drop to 2 capsules.
What to look for on the label
Magnesium L-threonate sold as Magtein (the form used in the trials), about 2 g of the compound = ~145 mg elemental magnesium per day.
We only name brands we have vetted and work with; a specific pick will appear here once one is approved.
03
L-theanine
Evidence B · moderate
100–400 mg (start at 200 mg), with the magnesium, 30–60 minutes before bed. Supports a quieter mind at bedtime without sedation. Useful when the problem is racing thoughts rather than heat.
What the research shows: A 2025 meta-analysis of randomized trials found L-theanine modestly improved self-rated sleep outcomes. Doses in the trials were mostly 200–400 mg. (PMID 40056718, PMID 31623400)
- Generally well tolerated. It can add to the effect of blood-pressure medicines and sedatives; check if you take them.
- Huberman’s own caution: skip theanine if you get overly intense dreams, sleepwalk or have night terrors.
What to look for on the label
L-theanine (Suntheanine or plain L-theanine), 100–200 mg per capsule.
We only name brands we have vetted and work with; a specific pick will appear here once one is approved.

What we left out, and why

Magnesium oxide

Poorly absorbed and mostly laxative at useful doses. It is cheap for a reason.

Magnesium sleep sprays and lotions

There is no good evidence that magnesium absorbed through the skin raises blood levels meaningfully.

Mega-dosing

More is not better. Above 350 mg/day of supplemental magnesium, diarrhea and cramping get common, and people with kidney disease can build up dangerous levels.

Safety and interactions

Not medical advice. Ask a pharmacist before starting if you take prescription medicines.
Separate magnesium from levothyroxine, tetracycline or quinolone antibiotics and bisphosphonates by at least 2–4 hours.
Kidney disease: do not supplement magnesium without your clinician.
Supplements are not evaluated by the FDA to diagnose, treat, cure or prevent any disease.

FAQ

Which magnesium is best for sleep?

Magnesium bisglycinate (glycinate) has the most direct sleep evidence, including a 2025 randomized trial using 250 mg elemental magnesium per day, and it is gentle on the gut and inexpensive. Magnesium L-threonate is a reasonable premium choice if you also want next-day focus.

Magnesium glycinate vs threonate: what is the difference?

Glycinate delivers more elemental magnesium per dollar and is the everyday sleep pick. L-threonate (Magtein) was designed to raise brain magnesium; a 21-day trial found better deep and REM sleep scores, but it gives only about 145 mg of magnesium per 2 g dose and costs roughly three times more.

Is magnesium citrate good for sleep?

Not really. Citrate is well absorbed but pulls water into the gut, so at sleep doses many people get loose stools. Use it for constipation, not sleep.

How much magnesium should I take at night?

200–350 mg of elemental magnesium, 30–60 minutes before bed. Stay at or under 350 mg/day of supplemental magnesium unless your clinician advises more.

Can I take magnesium every night?

Yes, at normal doses most healthy adults can take it nightly. People with kidney disease should not supplement without medical advice.

The sleep stack, minus the hype →Magnesium plus glycine, L-theanine and saffron, in order.The Huberman sleep stack, reviewed →Threonate, apigenin, theanine and glycine graded.Waking at 3 a.m. in perimenopause →When hot flashes, not magnesium, are the problem.All stacks →

Sources

Studies were checked on PubMed on Oct 7, 2026. Product prices come from each brand's own site on the same date.