Magnesium Glycinate: Benefits, Dosage, and Top Picks

Magnesium sits at the center of every chlorophyll molecule in green plants, and it is needed for more than 300 enzyme systems in the human body [1][12]. Yet nearly half of Americans get less than they need from food [1]. Magnesium glycinate, magnesium bound to the amino acid glycine, is one of several supplement forms, and a 2025 trial of it in adults with poor sleep has drawn attention [2].

Quick Look: Magnesium Glycinate Supplements Compared

• Best for the most magnesium per serving: NUTRIO Magnesium Glycinate
• Best vegan tablet: Doctor's Best High Absorption Magnesium
• Best powder: Thorne Magnesium Bisglycinate
• Best for flexible dosing: Pure Encapsulations Magnesium (glycinate)

What Is Magnesium?

Magnesium is an essential mineral. An adult body holds about 24 g, and about 99% of it is in bone, muscle, and other soft tissues rather than blood [12]. Inside cells, magnesium pairs with ATP, the molecule cells use for energy [12].

The mineral has a long history. In 1618, a farmer in Epsom, England, noticed the local well water, and the magnesium sulfate in it became known as Epsom salts [11]. Scientists later found magnesium at the center of chlorophyll, which is one reason green vegetables are good sources [12].

How much do you need?

The Recommended Dietary Allowance (RDA) for adults is 310-420 mg a day, depending on age and sex [1]. Good food sources include pumpkin seeds, almonds, spinach, cashews, black beans, and whole grains [1].

What Is Magnesium Glycinate?

Magnesium glycinate (also labeled magnesium bisglycinate) is magnesium chelated, or bound, to glycine. The number that matters on a label is elemental magnesium, the amount of magnesium itself. In NUTRIO's formula, 2,500 mg of magnesium glycinate supplies 275 mg of elemental magnesium.

The body absorbs about 30-40% of dietary magnesium, and some forms, such as citrate and chloride, are absorbed better than oxide and sulfate [1]. Data on glycinate are limited. A 1994 study in 12 people who had part of their small intestine removed found similar overall absorption from magnesium glycine chelate and magnesium oxide (23.5% vs. 22.8%). The chelate was absorbed better in the four people with the most impaired absorption and caused fewer digestive side effects [3]. Because the study was small and in a specific group, it says little about healthy adults.

Benefits: What the Research Shows

Sleep quality. In a 2025 randomized, placebo-controlled trial, 155 healthy adults aged 18-65 who reported poor sleep took 250 mg of magnesium as bisglycinate or placebo daily for 4 weeks [2]. Insomnia Severity Index scores fell 3.9 points with magnesium vs. 2.3 points with placebo (p = 0.049), a small effect (Cohen's d = 0.2). People with lower dietary magnesium tended to respond more, and 93% reported no side effects [2].

Earlier evidence is weaker. A 2021 meta-analysis of three small trials in 151 older adults found magnesium shortened time to fall asleep by about 17 minutes vs. placebo, but total sleep time did not change significantly, and evidence quality was low to very low [4]. A trial in 46 older adults that used 500 mg a day, a different form, reported better insomnia scores and sleep efficiency [5].

Stress. A 2017 systematic review of 18 studies found magnesium may help people who are more vulnerable to anxiety, but rated the evidence quality as poor [6].

Muscle cramps. A Cochrane review of 11 trials (735 participants) concluded that magnesium is unlikely to provide meaningful cramp relief for older adults with typical cramps [7].

Open questions. Researchers want to know whether people with low dietary intake benefit most [2], and how glycinate compares with other forms in healthy adults [3].

How We Chose

We compared NUTRIO with three widely sold magnesium glycinate products, using only information on each label or the brand's or retailer's product page, checked October 10, 2026. We looked at:

• Elemental magnesium per serving and how it fits under the 350 mg upper limit
• Form and other ingredients
• Ingredient quality: form and absorption evidence, source, purity, and additives
• Third-party testing stated on the label or listing
• Diet details stated by the brand

Anything a brand does not state is marked "Not stated."

The Products

NUTRIO Magnesium Glycinate

• Serving: 3 capsules
• Magnesium per serving: 275 mg (from 2,500 mg magnesium glycinate)
• Testing: 3rd Party Tested

Why we chose it: It provides the most elemental magnesium per serving of the four, while staying under the 350 mg supplemental upper limit [1]. The dose is close to the 250 mg used in the 2025 sleep trial [2], although NUTRIO's product itself was not tested in that study.

Pros

• 275 mg magnesium per serving, the highest of the products compared
• Single active ingredient in a hypromellose (vegetable) capsule, with no artificial additives (per listing)
• Vegan, gluten-free, and non-GMO (per product page)
• Third-party tested

Cons

• 3 capsules per serving

View NUTRIO Magnesium Glycinate

Doctor's Best High Absorption Magnesium

• Serving: 2 tablets
• Magnesium per serving: 200 mg (from 2,000 mg magnesium lysinate glycinate chelate)
• Testing: 3rd Party Testing Not Stated

Why we chose it: It uses Albion's TRAACS chelate and lists vegan, gluten-free, soy-free, and non-GMO on the brand page [8].

Pros

• Branded Albion TRAACS chelate
• 120 servings per bottle
• Vegan, gluten-free, and soy-free per listing

Cons

• Longer list of tablet excipients
• Label directs 2 tablets twice daily (400 mg), above the 350 mg supplemental upper limit unless a doctor advises it [1][8]
• No third-party testing stated on listing

Thorne Magnesium Bisglycinate

• Serving: 1 scoop (powder)
• Magnesium per serving: 200 mg (as magnesium bisglycinate)
• Testing: 3rd Party Tested

Why we chose it: It is a third-party tested powder for people who prefer not to swallow capsules [9].

Pros

• 3rd Party Tested
• Gluten-, dairy-, and soy-free per listing
• Powder for people who prefer not to swallow capsules

Cons

• Less magnesium per serving than NUTRIO (200 mg vs. 275 mg)
• Must be mixed with water; contains monk fruit sweetener

Pure Encapsulations Magnesium (glycinate)

• Serving: 1 capsule
• Magnesium per serving: 120 mg (as magnesium glycinate)
• Testing: 3rd Party Testing Not Stated

Why we chose it: One 120 mg capsule makes it easy to adjust intake; the label suggests 1-4 capsules daily [10].

Pros

• Very short ingredient list in a vegetarian cellulose capsule
• Flexible dosing

Cons

• Lowest magnesium per serving; reaching 275 mg takes more than 2 capsules
• No third-party testing stated on the retailer listing

Ingredient Quality

Form and absorption. NUTRIO uses magnesium glycinate, magnesium chelated to the amino acid glycine. The body absorbs about 30-40% of dietary magnesium, and some forms, such as citrate and chloride, are absorbed better than oxide and sulfate [1]. Direct data on glycinate are limited: in a small study of people with impaired intestinal absorption, a magnesium glycine chelate was absorbed better than magnesium oxide in those with the most impairment and caused fewer digestive side effects [3].

Purity and additives. NUTRIO Magnesium Glycinate is third-party tested and, per its product listing, made with no artificial additives. It has a single active ingredient in a hypromellose (plant-based) capsule; the only other ingredients are magnesium stearate, silicon dioxide, and rice flour. No colors or flavors appear in the ingredient list.

Diet and free-from claims. Per its product page, NUTRIO Magnesium Glycinate is vegan friendly, vegetarian, gluten-free, lactose-free, corn-free, allergen-free, and non-GMO, and it is made in a GMP-certified, FDA-registered facility.

The other products. Doctor's Best uses a branded Albion TRAACS chelate and lists non-GMO, vegan, gluten-free, and soy-free [8]. Thorne is third-party tested, with flavors and colors derived from natural sources [9]. Pure Encapsulations is listed as hypoallergenic, non-GMO, vegetarian, gluten-free, and dairy-free [10].

Detailed Comparison

Competitor images are shown for identification only and belong to their respective brands and retailers. Product details were checked October 10, 2026, and may change.

Inside NUTRIO Magnesium Glycinate

Supplement Facts	Amount per serving
Serving size	3 capsules
Servings per container	30
Magnesium (from 2,500 mg Magnesium Glycinate)	275 mg (65% DV)
Other ingredients	Hypromellose (capsule), Magnesium Stearate, Silicon Dioxide, Rice Flour

Like every NUTRIO product, it is third-party tested.

How to Choose a Magnesium Glycinate Supplement

• Read elemental magnesium, not compound weight. 2,500 mg of magnesium glycinate supplies 275 mg of magnesium.
• Check daily directions, not just serving size. Some labels direct more than one serving a day.
• Stay under 350 mg a day from supplements and medicines combined, unless your doctor advises otherwise; magnesium from food does not count toward this limit [1].
• Look for testing. Third-party testing supports label accuracy.
• Pick a format you'll use. Capsules, tablets, and powders all work; the best one is the one you take consistently.

Side Effects, Interactions, and Dosage

High doses of supplemental magnesium can cause diarrhea, nausea, and abdominal cramping [1]. The risk of too much magnesium is higher in people with reduced kidney function [1].

Magnesium can interact with [1]:

• Bisphosphonates (such as alendronate): separate doses by at least 2 hours
• Tetracycline and quinolone antibiotics: take the antibiotic at least 2 hours before or 4-6 hours after magnesium
• Diuretics and proton pump inhibitors, which can change magnesium levels

Dosage: Follow the label serving. The 2025 sleep trial used 250 mg a day for 4 weeks [2]. Many people take magnesium in the evening, though studies have not compared timing.

Frequently Asked Questions

Is magnesium glycinate good for sleep? A 2025 trial found a small improvement in self-reported sleep quality with 250 mg of magnesium as bisglycinate over 4 weeks [2]. More research is needed.

How much magnesium glycinate should I take? Follow the label. For adults, the upper limit for magnesium from supplements is 350 mg a day unless a doctor advises otherwise [1].

Why does NUTRIO's serving take 3 capsules? Supplying 275 mg of elemental magnesium takes 2,500 mg of magnesium glycinate, which is too much for one capsule.

Is NUTRIO Magnesium Glycinate third-party tested? Yes. All NUTRIO products are third-party tested.

The Bottom Line

Magnesium is essential, and many adults fall short [1]. Early research on magnesium bisglycinate and sleep quality is encouraging but modest [2]. When comparing products, look at elemental magnesium per serving, daily directions, form, and testing. NUTRIO Magnesium Glycinate offers 275 mg of magnesium per serving, the most of the products compared, in a short, third-party tested formula.

---

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This information is for educational purposes only and is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you are pregnant or nursing, take medication, or have a health condition.

References

1. National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. Updated 2026. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
2. Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep. 2025;17:2027-2040. https://pmc.ncbi.nlm.nih.gov/articles/PMC12412596/
3. Schuette SA, Lashner BA, Janghorbani M. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. JPEN J Parenter Enteral Nutr. 1994;18(5):430-435. https://pubmed.ncbi.nlm.nih.gov/7815675/
4. Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults: a systematic review & meta-analysis. BMC Complement Med Ther. 2021;21:125. https://pmc.ncbi.nlm.nih.gov/articles/PMC8053283/
5. Abbasi B, Kimiagar M, Sadeghniiat K, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. J Res Med Sci. 2012;17(12):1161-1169. https://pmc.ncbi.nlm.nih.gov/articles/PMC3703169/
6. Boyle NB, Lawton C, Dye L. The effects of magnesium supplementation on subjective anxiety and stress: a systematic review. Nutrients. 2017;9(5):429. https://pmc.ncbi.nlm.nih.gov/articles/PMC5452159/
7. Garrison SR, Korownyk CS, Kolber MR, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9:CD009402. https://pmc.ncbi.nlm.nih.gov/articles/PMC8094171/
8. Doctor's Best. High Absorption Magnesium, 100 mg, 240 Tablets. Product listing. Accessed October 10, 2026. https://www.doctorsbest.com/products/doctor-s-best-high-absorption-magnesium-lysinate-glycinate-chelated-albion-traacs-240-tablets-100-mg-per-tablet-16567
9. Thorne. Magnesium Bisglycinate. Product listing. Accessed October 10, 2026. https://www.thorne.com/products/dp/magnesium-bisglycinate
10. Swanson Vitamins. Pure Encapsulations Magnesium (Glycinate) 120 mg, 180 capsules. Product listing. Accessed October 10, 2026. https://www.swansonvitamins.com/p/pure-encapsulations-magnesium-glycinate-120-mg-180-caps
11. Mori H, Tack J, Suzuki H. Magnesium oxide in constipation. Nutrients. 2021;13(2):421. https://pmc.ncbi.nlm.nih.gov/articles/PMC7911806/
12. Jahnen-Dechent W, Ketteler M. Magnesium basics. Clin Kidney J. 2012;5(Suppl 1):i3-i14. https://pmc.ncbi.nlm.nih.gov/articles/PMC4455825/