Magnesium went viral as a sleep aid, and careful trials find a small effect

Key takeaways

• A 2021 review found just three small trials in older adults with insomnia, where magnesium cut the time to fall asleep by about 17 minutes, on low-quality evidence³.
• In a 2025 German trial of 155 adults who slept poorly, magnesium bisglycinate lowered insomnia scores slightly more than a placebo, an effect its authors called modest⁵.
• The main sleep trial of magnesium L-threonate counted an executive of the ingredient’s maker among its authors, and its deep- and REM-sleep gains were measured with a consumer sleep ring⁶⁷.
• About 48% of Americans get less magnesium from food and drinks than the average requirement for their age, and an ounce of pumpkin seeds supplies about 156 milligrams².
• Magnesium from supplements has a 350-milligram daily upper limit for adults, and people with kidney disease or on certain antibiotics, bone drugs or diuretics should check with a clinician first².

The NIH’s National Center for Complementary and Integrative Health (NCCIH) keeps a page titled “In the News: Magnesium Supplements for Sleep Disorders.” A viral drink helped put it there.

The “sleepy girl mocktail,” promoted on social media as a sleep aid, helped make magnesium a popular bedtime supplement online¹. So the agency, in an update dated January 2024, summed up what the science shows. Its verdict: magnesium pills have barely been studied as a fix for insomnia or other sleep problems¹.

The agency pointed to two reviews. One found three small studies, with 151 people in all, suggesting magnesium might help older adults with insomnia fall asleep faster. The reviewers judged those studies too weak to guide decisions¹.

The other review covered nine studies of 7,582 people and found conflicting results. Its authors asked for bigger trials lasting longer than 12 weeks¹.

Since then, researchers have tested two popular forms, glycinate and L-threonate. The results are real but modest, and the funding trail matters. This guide covers what the studies used, who might benefit, and how to check whether you need a pill at all.

Many people fall short on magnesium, but few are measured

The first question for sleep is whether you’re getting enough magnesium. The second is whether more would help.

The NIH Office of Dietary Supplements (ODS) lists these daily targets, called Recommended Dietary Allowances, or RDAs²:

Group	Daily RDA
Men 19–30	400 mg
Men 31 and older	420 mg
Women 19–30	310 mg
Women 31 and older	320 mg
Pregnancy	350–360 mg

Shortfalls are common. In national survey data from 2013 to 2016, 48% of Americans of all ages got less magnesium from food and drinks than the amount their age group needs on average². Men over 70 and teenagers were most likely to fall short².

A shortfall isn’t the same as a deficiency, though, and here the data run thin. The national survey hasn’t measured magnesium in people’s blood since 1974². Our article on vitamin and mineral shortfalls explains why missing a target is common while true deficiency is not.

Some groups face higher risk of running low, according to ODS: older adults, people with digestive diseases such as Crohn’s or celiac disease, people with type 2 diabetes, and people with alcohol dependence². Long-term use of acid-reflux drugs called proton pump inhibitors can lower magnesium, too².

The core evidence: three small trials in older adults

The review NCCIH cited was published in 2021 in BMC Complementary Medicine and Therapies by researchers Mah and Pitre³. They found only three randomized trials of magnesium pills versus placebo for insomnia in older adults, with 151 people across three countries³.

Pooled together, magnesium shortened the time to fall asleep by about 17 minutes³. Total sleep time rose by about 16 minutes, but that gain could have been chance³.

The reviewers rated all three trials at moderate to high risk of bias. They graded the evidence low to very low quality and called the research “substandard” for doctors trying to make well-informed recommendations³.

A 2012 trial from Iran shows what these studies look like. In that double-blind trial, 46 older adults with insomnia took 500 milligrams of magnesium or a placebo every day for eight weeks⁴. The magnesium group improved on an insomnia questionnaire, sleep efficiency and time to fall asleep⁴. Their blood levels of melatonin, a sleep-timing hormone, rose, and cortisol, a stress hormone, fell⁴.

Those sleep results all came from questionnaires and sleep logs, not lab measurements⁴. The published abstract also doesn’t say whether 500 milligrams meant elemental magnesium, the amount of the mineral itself. If it did, that’s above the 350-milligram upper limit for supplements².

Glycinate and threonate: newer trials, and who paid for them

In supplements, magnesium comes bound to a partner compound, such as oxide or citrate, and labels list the elemental magnesium². ODS says some forms, such as citrate, chloride, lactate and aspartate, appear to be absorbed better than oxide and sulfate, based on small studies². Oxide, carbonate, chloride and gluconate are the forms most often tied to diarrhea². The ODS fact sheet doesn’t mention glycinate or threonate.

Magnesium bisglycinate. This form pairs magnesium with glycine, an amino acid. The first sleep trial we found that tested glycinate itself came out in 2025.

Researchers at Leibniz University Hannover in Germany, with a colleague in Australia, tested it in 155 adults with self-reported poor sleep⁵. Each night, 30 to 60 minutes before bed, participants took capsules supplying 250 milligrams of elemental magnesium and about 1.5 grams of glycine, or a look-alike placebo, for four weeks⁵.

Insomnia scores fell 3.9 points with magnesium and 2.3 points with placebo⁵. That difference barely cleared the bar for statistical significance, and the authors called the effect modest⁵. Forty-one people improved by 6 points or more, a drop the authors counted as clinically meaningful: 26 on magnesium and 15 on placebo⁵. Daytime sleepiness, fatigue, stress and mood didn’t differ between groups⁵.

The funding was academic: the university’s own Institute of Food and One Health paid for it⁵. An Austrian supplement company, Biogena, made the capsules, though the paper doesn’t say whether it donated them. One author, Adrian Lopresti, runs Clinical Research Australia, a contract research firm that receives funding from supplement companies⁵.

What about the glycine? Earlier research by a group including scientists at the Japanese company Ajinomoto found that 3 grams of glycine before bed improved self-rated sleep¹⁰. In one of that group’s later studies, three of five authors worked at Ajinomoto and all seven volunteers analyzed were company employees, though the paper declared no commercial conflicts¹⁰. The glycinate capsules supplied about half the glycine those studies used.

Magnesium L-threonate. This form is sold under the brand name Magtein, and the trial’s authors describe it as a form that reaches the brain⁶. In a 2024 trial, 80 adults ages 35 to 55 with sleep complaints took 1 gram a day or a placebo for 21 days⁶. The threonate group scored better on deep and REM sleep, as measured by an Oura ring, and reported better energy, mood and alertness⁶.

Two cautions apply. A co-author, Jennifer Gu, was quoted in a trade-press report as one of the study’s principal investigators and as vice president of research and development at ThreoTech, the company behind Magtein⁷. And consumer rings estimate sleep stages roughly, as our article on sleep trackers explains.

A second Magtein trial, published in January 2026 by Lopresti and a colleague, tested 2 grams a day in 100 adults for six weeks⁸. Its main goal was thinking skills. On sleep, one questionnaire measure improved, while two others didn’t, and the ring showed no change in sleep stages⁸. That 2-gram dose held just 145 milligrams of elemental magnesium⁸.

We couldn’t view that paper’s funding statement. But a similar Magtein trial that Clinical Research Australia registered in 2025 lists AIDP Inc., a U.S. company, as its funder⁹.

Company money doesn’t make results false. It’s a reason to wait for independent replication, the same standard you’d apply to a drug company.

What the evidence shows, claim by claim

Claim	Evidence level	What it rests on
Magnesium helps older adults with insomnia fall asleep faster	Promising but early	Three small trials; about 17 minutes faster; low-quality evidence3
Magnesium bisglycinate eases poor sleep in adults	Promising but early	One 155-person trial; small effect; self-reported only5
Magnesium L-threonate improves deep and REM sleep	Not enough evidence	One maker-linked trial using a consumer ring; a second trial saw no stage changes678
One form works better than another for sleep	Not enough evidence	We found no head-to-head sleep trials comparing forms
Glycine at 3 grams improves self-rated sleep	Promising but early	Small studies from a company-linked research group10
Magnesium prevents nighttime leg cramps in older adults	Evidence says no, or unsafe	A Cochrane review found it unlikely to help11
Magnesium baths, sprays or flakes raise your magnesium through the skin	Not enough evidence	A review found the claims scientifically unsupported12

Leg cramps, Epsom salts and the mocktail

Leg cramps. If cramps jolt you awake, magnesium can look like a natural fix. A 2020 Cochrane review, from the international group that pools trial results, looked at 11 trials with 735 people¹¹. For ordinary cramps in older adults, magnesium was “unlikely” to prevent them in any meaningful way¹¹. Results in pregnancy conflicted¹¹. Diarrhea was common, affecting 11% to 37% of people taking magnesium in the trials that tracked it¹¹. Our stretching article in this series covers the calf-stretch approach, and restless legs gets its own article.

Epsom salt baths. Epsom salt soaks, magnesium sprays, oils and bath flakes are sold on the promise that magnesium passes through the skin. A review in the journal Nutrients, which looked at sprays, flakes and magnesium salt baths, concluded that the case for transdermal magnesium is scientifically unsupported¹². A warm bath may still help you wind down, for reasons our evening-routine article explains, but don’t count it as a magnesium dose.

The mocktail. If you make the viral drink with magnesium powder, the powder counts toward your 350-milligram daily limit from supplements². Read the label for elemental magnesium and the form. ODS says oxide, carbonate, chloride and gluconate are the forms most often linked to diarrhea². The drink’s other ingredients get their own review in our guide to sleep-aid claims.

A magnesium check: food first, then decide

Start with your plate. The upper limit doesn’t apply to magnesium from food, because healthy kidneys flush out the extra². That makes food the low-risk place to begin.

Step 1: Count your food. These are ODS figures for common sources²:

Food	Serving	Magnesium
Pumpkin seeds, roasted	1 ounce	156 mg
Chia seeds	1 ounce	111 mg
Almonds, dry roasted	1 ounce	80 mg
Spinach, boiled	½ cup	78 mg
Cashews, dry roasted	1 ounce	74 mg
Peanuts, oil roasted	¼ cup	63 mg
Soymilk, plain	1 cup	61 mg
Black beans, cooked	½ cup	60 mg
Edamame, shelled, cooked	½ cup	50 mg

This is a sample day built from that table: an ounce of pumpkin seeds on oatmeal, a half cup of black beans at lunch, a half cup of spinach at dinner and an ounce of almonds as a snack. Not counting the oatmeal, that adds up to 374 milligrams, above the RDA for women 31 and older and nearly 90% of the target for men that age².

Step 2: Ask whether you’re in a higher-risk group. Older age, Crohn’s or celiac disease, type 2 diabetes, alcohol dependence, long-term reflux pills or water pills called loop or thiazide diuretics can all lower magnesium². If one fits you, ask your clinician whether testing or a supplement makes sense.

Step 3: If you try a supplement, match the studies. The 2025 glycinate trial used 250 milligrams of elemental magnesium, taken 30 to 60 minutes before bed⁵. That stays under the 350-milligram limit². Count every product that contains magnesium, including sleep blends and the mocktail powder. Our stack audit shows how those add up and why some magnesium blends also carry vitamin B6.

Step 4: Skip it or ask first if any of these apply.

• Kidney disease. Weak kidneys can’t clear extra magnesium, which raises the risk of toxicity².
• Certain antibiotics. Magnesium binds tetracyclines such as doxycycline and quinolones such as ciprofloxacin. Space them out: swallow the antibiotic two or more hours ahead of magnesium, or wait four to six hours after it².
• Osteoporosis pills. Separate oral bisphosphonates such as alendronate from magnesium by at least 2 hours².
• Diuretics. Some raise magnesium losses, while potassium-sparing types such as spironolactone hold magnesium in².
• Children. Supplement limits are much lower: 65 milligrams a day for ages 1 to 3 and 110 for ages 4 to 8². Ask your pediatrician.
• Pregnancy. Needs rise to 350 to 360 milligrams a day, but the supplement limit stays at 350². Ask your prenatal clinician.

Step 5: Run a four-week trial. The glycinate trial lasted four weeks⁵. Rate your sleep each morning from 0 to 10 for one week before you start, then keep rating for four weeks on the same dose. Stop if you get diarrhea, nausea or cramping, which are signs of too much². Our self-trial guide explains how to read the results fairly.

Supplement rules, and a food-first instinct that holds up

In the U.S., magnesium supplements don’t need FDA approval, and the FDA doesn’t check whether they work before they’re sold¹³. A label may say a product supports a body function, such as relaxation or sleep, if it carries the standard disclaimer that the FDA hasn’t evaluated the claim¹³. Our article on structure-and-function claims explains what that wording does and doesn’t promise.

Many natural-health readers prefer to get nutrients from food. Here, that instinct lines up with the science. Food-based magnesium has no upper limit for healthy people, while pills do². And the research behind the newer branded forms comes with company ties worth weighing, just as you’d weigh a drug maker’s own trial.

When poor sleep needs more than magnesium

MedlinePlus, from the National Library of Medicine, lists signs that you may have a sleep disorder and should talk with a health care provider¹⁴:

• You regularly take more than 30 minutes to fall asleep¹⁴.
• You wake several times and struggle to get back to sleep, or you wake too early¹⁴.
• You often feel sleepy during the day or fall asleep at the wrong times¹⁴.
• A bed partner hears loud snoring, gasping, choking or pauses in your breathing¹⁴.
• You feel creeping or tingling in your legs in the evening that eases when you move¹⁴.

For chronic insomnia, NCCIH says cognitive behavioral therapy for insomnia, or CBT-I, is the most strongly recommended treatment¹⁵. A coming article in this series covers when to seek that kind of help.

Very large doses of magnesium, usually from laxatives or antacids, have caused low blood pressure, vomiting, trouble breathing, irregular heartbeat and cardiac arrest². If someone has trouble breathing or an irregular heartbeat after taking a lot of magnesium, call 911². For a child who swallowed magnesium products, call Poison Control at 1-800-222-1222. Report a bad reaction to a supplement to the FDA at 800-FDA-1088¹³.

Questions readers ask

The bottom line

Magnesium may help some people fall asleep a bit faster, especially older adults with insomnia, but the trials are few, short and mostly self-reported. The trendiest forms rest on one or two studies each, some tied to the companies that sell them.

Start with magnesium-rich foods, which carry no upper limit for healthy people. If you try a supplement, use a dose from the studies, stay at or under 350 milligrams a day, check your medicines and kidneys, and give it four honest weeks. If sleep stays broken, see a clinician about CBT-I.

Related reading

• A stack of safe supplements can add up to an unsafe dose
• Shortfalls in vitamins and minerals are common, but true deficiencies are not
• Sleep trackers count your hours well, but their sleep stages are rough guesses
• Who paid for the study matters, even when the science is real
• How to compare two supplements that look identical

Sources

1. National Center for Complementary and Integrative Health. “In the News: Magnesium Supplements for Sleep Disorders.” NIH, updated January 2024. nccih.nih.gov
2. NIH Office of Dietary Supplements. “Magnesium: Fact Sheet for Health Professionals.” NIH, updated January 6, 2026. ods.od.nih.gov
3. Mah J, Pitre T. “Oral Magnesium Supplementation for Insomnia in Older Adults: A Systematic Review & Meta-Analysis.” BMC Complementary Medicine and Therapies, 2021;21:125. agris.fao.org
4. Abbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B. “The Effect of Magnesium Supplementation on Primary Insomnia in Elderly: A Double-Blind Placebo-Controlled Clinical Trial.” Journal of Research in Medical Sciences, 2012;17(12):1161-1169. pubmed.ncbi.nlm.nih.gov
5. Schuster J, Cycelskij I, Lopresti A, Hahn A. “Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial.” Nature and Science of Sleep, 2025;17:2027-2040. dovepress.com
6. Hausenblas HA, Lynch T, Hooper S, Shrestha A, Rosendale D, Gu J. “Magnesium-L-Threonate Improves Sleep Quality and Daytime Functioning in Adults With Self-Reported Sleep Problems: A Randomized Controlled Trial.” Sleep Medicine: X, 2024;8:100121. pubmed.ncbi.nlm.nih.gov
7. Nutritional Outlook (trade press). “Recent Study Shows That Magtein Supports Sleep Quality and Daytime Functioning.” October 4, 2024. nutritionaloutlook.com
8. Lopresti AL, Smith SJ. “The Effects of Magnesium L-Threonate (Magtein) on Cognitive Performance and Sleep Quality in Adults: A Randomised, Double-Blind, Placebo-Controlled Trial.” Frontiers in Nutrition, 2025;12 (published online January 2026). frontiersin.org
9. Australian New Zealand Clinical Trials Registry. “An Examination Into the Effects of Magtein on Cognitive Performance and Sleep Quality in Adults Experiencing Subjective Cognitive Difficulties and Sleep Dissatisfaction.” ACTRN12625000805471, registered July 29, 2025. anzctr.org.au
10. Bannai M, Kawai N, Ono K, Nakahara K, Murakami N. “The Effects of Glycine on Subjective Daytime Performance in Partially Sleep-Restricted Healthy Volunteers.” Frontiers in Neurology, 2012;3:61. frontiersin.org
11. Garrison SR, Korownyk CS, Kolber MR, et al. “Magnesium for Skeletal Muscle Cramps.” Cochrane Database of Systematic Reviews, 2020, Issue 9, CD009402. cochranelibrary.com
12. Gröber U, Werner T, Vormann J, Kisters K. “Myth or Reality: Transdermal Magnesium?” Nutrients, 2017;9(8):813. nutrition-evidence.com
13. NIH Office of Dietary Supplements. “Dietary Supplements: What You Need to Know.” NIH, updated January 4, 2023. ods.od.nih.gov
14. MedlinePlus. “Sleep Disorders.” National Library of Medicine, updated December 4, 2025. medlineplus.gov
15. National Center for Complementary and Integrative Health. “Sleep Disorders and Complementary Health Approaches.” NIH, updated May 2024. nccih.nih.gov