Magnesium glycinate
Summary
Magnesium glycinate is magnesium bound to glycine, about 14% elemental magnesium by weight. In one 155-person randomized trial, 250 mg/day of magnesium as bisglycinate modestly reduced insomnia severity after four weeks (grade C). Blood-pressure, glucose and migraine data come from other or mixed forms.
Key facts
- Magnesium salt of glycine, Mg(C2H4NO2)2; also sold as bisglycinate or chelate[2]
- 14.1% of compound weight (anhydrous): 500 mg compound ≈ 70 mg magnesium[2]
- Insomnia severity ↓ (C), one RCT, n=155[3]
- 8 rows across sleep, blood pressure, blood sugar, migraine, anxiety and muscle cramps; 1 tested glycinate itself[3][22][23][25][21][6]
- No overall difference (23.5% vs 22.8%) in 12 patients; higher in the 4 with poorest oxide absorption[4]
- Adults 310–420 mg/day magnesium (all sources); UL 350 mg/day from supplements[1]
- Same as all magnesium: bisphosphonates, tetracycline and quinolone antibiotics, diuretics, long-term PPIs[1]
- Toxicity risk rises with impaired kidney function; very large laxative or antacid doses (over 5,000 mg/day) have caused toxicity[1]
- 8 graded human outcomes on this page
- October 9, 2026
How it works
ProposedThe magnesium in glycinate acts like magnesium from any form once absorbed. Small studies suggest part of magnesium diglycinate may be absorbed intact through a dipeptide transport pathway, which is a proposed explanation, not an established one.[4]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Blood pressure | Grade A | Improved | Meta-analysis of 34 trials · n = 2,028 · 2016 | 1 row |
| Anxiety & stress | Grade C | Mixed | Systematic review of 8 trials · n = 975 · 2017 | 1 row |
| Migraine | Grade C | Improved | Meta-analysis of 10 trials · n = 789 · 2016 | 2 rows |
| Blood sugar | Grade C | Improved | Meta-analysis of 9 trials · n = 670 · 2016 | 1 row |
| Sleep | Grade C | Improved | RCT · n = 155 · 2025 | 2 rows |
| Muscle cramps | No effect | No effect | Meta-analysis of 5 trials · n = 307 · 2020 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Blood pressure | Improved | Grade A | Meta-analysis · n = 2,028 · 2016 34 double-blind placebo-controlled trials in normotensive and hypertensive adults Form: Various oral forms · Dose: Median 368 mg/day magnesium · Duration: Median 3 months Systolic blood pressure fell by 2.00 mm Hg and diastolic by 1.78 mm Hg versus placebo, with a 0.05 mmol/L rise in serum magnesium. A small average effect. | 27402922 (opens PubMed)Source [22] |
| Subjective anxiety (anxiety-prone groups) | Mixed | Grade C | Systematic review · n = 975 · 2017 8 trials in mildly anxious adults (18 trials overall, including PMS, postpartum and hypertension samples) Form: Mostly magnesium lactate with vitamin B6, or multi-ingredient products; one trial used citrate · Dose: 48–300 mg/day magnesium, often combined with other ingredients · Duration: 5 days to 12 weeks 4 of 8 trials in mildly anxious samples, 4 of 7 in PMS samples and 1 of 2 in hypertensive samples reported less self-rated anxiety; no effect postpartum. The reviewers rated the evidence quality as poor. | 28445426 (opens PubMed)Source [21] |
| Migraine attack frequency | Improved | Grade C | Meta-analysis · n = 789 · 2016 10 RCTs of oral magnesium for migraine prophylaxis Form: Oral magnesium (forms varied by trial) · Dose: Varied by trial · Duration: Varied by trial Oral magnesium reduced migraine frequency (odds ratio 0.20) and intensity (OR 0.27) versus control; some included trials did not use adequate randomization. A 2012 AAN/AHS guideline rated magnesium 'probably effective' for prevention (Level B). | 26752497 (opens PubMed)Source [25] |
| Fasting glucose (people with diabetes) | Improved | Grade C | Meta-analysis · n = 670 · 2016 9 double-blind RCTs in people with diabetes (part of an 18-trial review) Form: Oral magnesium (forms varied by trial) · Dose: Varied by trial · Duration: Varied by trial Fasting plasma glucose was lower than placebo (standardized mean difference −0.40, 95% CI −0.80 to −0.00) with high heterogeneity (I² = 77%). In people at high risk of diabetes, 2-hour glucose after a glucose tolerance test improved (3 studies). | 27530471 (opens PubMed)Source [23] |
| Insomnia severity | Improved | Grade C | RCT · n = 155 · 2025 Healthy adults aged 18–65 reporting poor sleep quality Form: magnesium bisglycinate · Dose: 250 mg/day elemental magnesium · Duration: 4 weeks (primary analysis) Insomnia Severity Index fell 3.9 points versus 2.3 with placebo (p = 0.049); a small effect (Cohen's d = 0.2). No differences in other psychological outcomes. | 40918053 (opens PubMed)Source [3] |
| Time to fall asleep (older adults) | Improved | Grade C | Meta-analysis · n = 151 · 2021 3 RCTs in older adults with insomnia Form: Oral magnesium (forms varied by trial) · Dose: Varied by trial · Duration: Varied by trial Sleep onset latency 17.4 minutes shorter than placebo; low to very low quality evidence. | 33865376 (opens PubMed)Source [5] |
| Migraine attack frequency (citrate trial) | Improved | Grade C | RCT · n = 81 · 1996 Adults 18–65 with migraine, mean 3.6 attacks per month Form: Trimagnesium dicitrate · Dose: 600 mg/day magnesium · Duration: 12 weeks In weeks 9–12, attack frequency fell 41.6% with magnesium versus 15.8% with placebo (p < 0.05). Diarrhea in 18.6% and gastric irritation in 4.7%. | 8792038 (opens PubMed)Source [10] |
| Muscle cramps (older adults) | No effect | No effect | Meta-analysis · n = 307 · 2020 Cochrane review, idiopathic cramps in mostly older adults (5 trials) Form: Oral magnesium (forms varied by trial) · Dose: Varied by trial · Duration: 4 weeks No meaningful difference from placebo in cramps per week (moderate-certainty evidence). | 32956536 (opens PubMed)Source [6] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Magnesium glycinate (bisglycinate) | 14.1%[2] | In 12 people with ileal resection, overall absorption of a 100 mg dose did not differ from oxide (23.5% vs 22.8%), but was higher in the 4 with the poorest oxide absorption (23.5% vs 11.8%).[4] | Better tolerated than oxide by all 12 patients in that small crossover trial.[4] | Insomnia severity in adults reporting poor sleep (one RCT). |
| Magnesium citrate | 16.2%[7] | More soluble and more bioavailable than oxide by urinary magnesium in short studies; in a 60-day RCT (n=46) citrate gave the highest serum magnesium of the forms compared.[8][9] | Diarrhea was reported by 18.6% of participants at 600 mg/day in a 12-week migraine trial.[10] | Arterial stiffness and blood pressure (null), bone-turnover markers, migraine attack frequency. |
| Magnesium L-threonate | 8.3%[11] | No head-to-head human absorption data. Raised brain magnesium in rats (animal data).[12] | Described as well tolerated in 3- to 6-week trials of 1–2 g/day.[13][14] | Cognitive test performance and sleep quality (small RCTs). |
| Magnesium malate | 15.5%[15] | No head-to-head human absorption data in our sources. | No form-specific human tolerance data in our sources. | No graded human outcome trials in our sources. |
| Magnesium taurate | 8.9%[16] | No head-to-head human absorption data in our sources. | No form-specific human tolerance data in our sources. | No graded human outcome trials in our sources. |
| Magnesium oxide | 60.3%[17] | Lowest of the forms tested: about 4% fractional absorption in one comparison; poorly soluble in water.[18][8] | One of the forms most often reported to cause diarrhea, per NIH ODS.[1] | Arterial stiffness and blood pressure (null in one 24-week trial). |
- Magnesium oxide603 mg
- Magnesium citrate162 mg
- Magnesium malate155 mg
- Magnesium glycinate (bisglycinate)141 mg
- Magnesium taurate89 mg
- Magnesium L-threonate83 mg
Compound weight → elemental magnesium
500 mg magnesium glycinate (bisglycinate) ≈ 71 mg elemental magnesium
Studied doses, daily needs and limits
Doses studied in human trials ranged from a single 100 mg dose (absorption study) to 250 mg/day of elemental magnesium as bisglycinate for 4 weeks (sleep trial).[3][4]
Intake reference: Adult RDA 310–420 mg/day from all sources (by age and sex). Upper limit for supplemental magnesium: 350 mg/day for adults.[1] The upper limit covers supplements and medicines only, not magnesium in food. NIH ODS fact sheet (updated January 6, 2026).
Recommended intake and upper limit by age and sex
| Age | Male | Female | Pregnancy | Lactation | Upper limit (UL) |
|---|---|---|---|---|---|
| 0–6 months (AI) | 30 mg | 30 mg | — | — | Not set |
| 7–12 months (AI) | 75 mg | 75 mg | — | — | Not set |
| 1–3 years | 80 mg | 80 mg | — | — | 65 mg |
| 4–8 years | 130 mg | 130 mg | — | — | 110 mg |
| 9–13 years | 240 mg | 240 mg | — | — | 350 mg |
| 14–18 years | 410 mg | 360 mg | 400 mg | 360 mg | 350 mg |
| 19–30 years | 400 mg | 310 mg | 350 mg | 310 mg | 350 mg |
| 31–50 years | 420 mg | 320 mg | 360 mg | 320 mg | 350 mg |
| 51+ years | 420 mg | 320 mg | — | — | 350 mg |
Dose math: how much compound supplies that much magnesium
| Form (elemental %) | 250 mg magnesium250 mg/day: dose in the bisglycinate sleep trial | 300 mg magnesium300 mg/day: amount the blood-pressure meta-analysis linked to an effect | 350 mg magnesium350 mg/day: adult upper limit from supplements (a ceiling, not a target) |
|---|---|---|---|
| Magnesium glycinate (bisglycinate) (14.1%) | ≈ 1,770 mg compound | ≈ 2,130 mg compound | ≈ 2,480 mg compound |
| Magnesium citrate (16.2%) | ≈ 1,540 mg compound | ≈ 1,850 mg compound | ≈ 2,160 mg compound |
| Magnesium L-threonate (8.3%) | ≈ 3,010 mg compound | ≈ 3,610 mg compound | ≈ 4,220 mg compound |
| Magnesium malate (15.5%) | ≈ 1,610 mg compound | ≈ 1,940 mg compound | ≈ 2,260 mg compound |
| Magnesium taurate (8.9%) | ≈ 2,810 mg compound | ≈ 3,370 mg compound | ≈ 3,930 mg compound |
| Magnesium oxide (60.3%) | ≈ 410 mg compound | ≈ 500 mg compound | ≈ 580 mg compound |
How long trials ran before effects were measured
When each outcome was assessed in the cited trials. It is not a promise of when anyone will notice a change.
- Week 4 (primary endpoint) · Change in Insomnia Severity Index from baseline to week 4 in the 155-person bisglycinate trial[3]
- About 1 month or more · Dose–response analysis across 34 trials: 300 mg/day or 1 month was enough to raise serum magnesium and lower blood pressure; median trial length 3 months[22]
- Weeks 9–12 of a 12-week trial · Attack frequency compared with a 4-week baseline, at 600 mg/day as trimagnesium dicitrate[10]
- No effect at 4 weeks · Cochrane review primary endpoint: cramps per week at four weeks[6]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- Oral bisphosphonatesNIH fact sheetMagnesium-rich supplements or medicines can reduce bisphosphonate absorption; NIH ODS notes separating them by at least 2 hours.[1]
- Tetracycline and quinolone antibioticsNIH fact sheetMagnesium can form insoluble complexes with these antibiotics; NIH ODS notes taking the antibiotic at least 2 hours before or 4–6 hours after magnesium.[1]
- Potassium-sparing diureticsNIH fact sheetReduce urinary magnesium excretion.[1]
Medicines that can lower levels
- Loop and thiazide diureticsNIH fact sheetLong-term use can increase urinary magnesium loss and lead to depletion.[1]
- Proton pump inhibitors (long-term)FDA safety communicationUse typically longer than a year can cause low blood magnesium; in about 25% of cases FDA reviewed, supplements did not correct it and the PPI was stopped.[19][1]
Other supplements
- High-dose zincPK studyLowered magnesium absorption and magnesium balance in a metabolic-ward study of adult men.[20]
Who should be careful
- Kidney problems
- The risk of magnesium toxicity rises with impaired kidney function, because the kidneys remove excess magnesium.[1]
- High intakes and digestive effects
- High doses from supplements or medicines often cause diarrhea, nausea and abdominal cramping. The adult upper limit for supplemental magnesium is 350 mg/day; very large doses from laxatives or antacids (typically over 5,000 mg/day) have caused toxicity.[1]
- Pregnancy and breastfeeding
- The RDA is 350–400 mg/day in pregnancy and 310–360 mg/day during lactation (all sources), and the 350 mg/day upper limit for supplemental magnesium still applies.[1]
- Children
- Upper limits for supplemental magnesium are lower: 65 mg/day at ages 1–3 and 110 mg/day at ages 4–8.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Kidney safety
The kidneys are what keep magnesium in balance, so kidney function changes the safety picture more than the form does.
- How the body clears magnesium
- Magnesium balance is largely controlled by the kidneys, which typically excrete about 120 mg a day into urine and excrete less when status is low. Too much magnesium from food is not a risk in healthy people because the kidneys remove the excess.[1]
- Reduced kidney function
- The risk of magnesium toxicity increases with impaired kidney function or kidney failure, because the ability to remove excess magnesium is reduced or lost. People with kidney disease should get any magnesium supplement cleared by their kidney care team.[1]
- Warning signs of too much
- Toxicity usually appears once serum magnesium exceeds about 1.74–2.61 mmol/L (normal is 0.75–0.95). Early signs include low blood pressure, nausea, vomiting, facial flushing, urine retention and lethargy; severe cases progress to muscle weakness, difficulty breathing, irregular heartbeat and cardiac arrest.[1]
- Laxatives and antacids add up
- Very large doses from magnesium-containing laxatives and antacids (typically over 5,000 mg/day) have caused toxicity, including deaths. One tablespoon of a common milk of magnesia product supplies 500 mg of magnesium.[1]
- A normal blood test is not the whole story
- Less than 1% of the body's magnesium is in serum, so serum levels do not reliably show total-body status; no single test is considered satisfactory.[1]
Food sources
| Food | Serving | Amount |
|---|---|---|
| Pumpkin seeds, roasted | 1 ounce | 156 mg[1] |
| Chia seeds | 1 ounce | 111 mg[1] |
| Almonds, dry roasted | 1 ounce | 80 mg[1] |
| Spinach, boiled | ½ cup | 78 mg[1] |
| Cashews, dry roasted | 1 ounce | 74 mg[1] |
| Peanuts, oil roasted | ¼ cup | 63 mg[1] |
| Shredded wheat cereal | 2 large biscuits | 61 mg[1] |
| Soymilk, plain or vanilla | 1 cup | 61 mg[1] |
| Black beans, cooked | ½ cup | 60 mg[1] |
| Edamame, shelled, cooked | ½ cup | 50 mg[1] |
| Peanut butter, smooth | 2 tablespoons | 49 mg[1] |
| Potato, baked with skin | 3.5 ounces | 43 mg[1] |
| Brown rice, cooked | ½ cup | 42 mg[1] |
| Yogurt, plain, low fat | 8 ounces | 42 mg[1] |
| Banana | 1 medium | 32 mg[1] |
| Milk | 1 cup | 27 mg[1] |
| Salmon, Atlantic, farmed, cooked | 3 ounces | 26 mg[1] |
- Pumpkin seeds, roasted156 mg
- Chia seeds111 mg
- Almonds, dry roasted80 mg
- Spinach, boiled78 mg
- Cashews, dry roasted74 mg
- Peanuts, oil roasted63 mg
- Shredded wheat cereal61 mg
- Soymilk, plain or vanilla61 mg
- Black beans, cooked60 mg
- Edamame, shelled, cooked50 mg
How to read the label
- Read the Supplement Facts panel, not the front of the bottleThe amount listed for magnesium in Supplement Facts is the weight of magnesium itself, not of the whole magnesium glycinate compound. FDA requires the mineral's weight there, not the salt's.[1][26]
- Find the form in parenthesesLabels may name the source next to the nutrient, for example "Magnesium (as magnesium bisglycinate chelate)". A magnesium salt used only as a binder, such as magnesium stearate, appears in the ingredient list below the panel instead.[26]
- Check what one serving meansServing Size is the most the label recommends at one time, so one serving can be two, three or four capsules. Divide by the capsule count before comparing products.[26]
- Convert front-label compound weights yourselfIf a front label says 500 mg of magnesium glycinate, that is about 70 mg of magnesium at 14.1%. The converter in the Forms section does this for any form.[2]
- Add up every source against the 350 mg limitThe adult upper limit of 350 mg/day counts magnesium from all supplements and medicines combined, including multivitamins, antacids and laxatives, but not food.[1]
Cost per studied dose, without the sales pitch
Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.
Cost per studied dose
Enter the price, servings and the amount per serving from your label.
Articles about Magnesium glycinate
Plain-English answers to common questions, built on the evidence above.
Frequently asked questions
Is magnesium glycinate the same as bisglycinate?
Yes in practice. Bisglycinate (or diglycinate) names the usual form, one magnesium atom bound to two glycine molecules, about 14% magnesium by weight.[2]
How much magnesium is in 500 mg of magnesium glycinate?
About 70 mg of elemental magnesium, based on the 14.1% magnesium content of anhydrous magnesium bisglycinate. Supplement Facts panels list the elemental amount.[2][1]
Does magnesium glycinate help with sleep?
One randomized trial of 155 adults reporting poor sleep found 250 mg/day of magnesium as bisglycinate modestly lowered insomnia severity after four weeks; the effect was small. Larger and longer trials with objective sleep measures are needed.[3]
Is magnesium glycinate gentler on the stomach?
In one small crossover trial of 12 patients with ileal resection, the glycinate chelate was better tolerated than magnesium oxide by all participants. Larger tolerance comparisons are lacking.[4]
How much magnesium glycinate did studies use?
The sleep trial used 250 mg/day of elemental magnesium as bisglycinate for four weeks, which is roughly 1,770 mg of the compound. The adult upper limit for magnesium from supplements is 350 mg/day.[3][2][1]
How long did it take for effects to show in trials?
The glycinate sleep trial measured its main result at week 4. Blood-pressure trials suggest about a month or more, and the migraine trial assessed attacks in weeks 9 to 12. These are measurement points, not guarantees.[3][22][10]
Is magnesium glycinate safe with kidney disease?
Reduced kidney function raises the risk of magnesium building up to toxic levels, whatever the form. People with kidney disease should only use magnesium supplements with their clinician's approval.[1]
Sources
- [1]Magnesium: Fact Sheet for Health Professionals (updated January 6, 2026). NIH Office of Dietary Supplements, 2026. fact-sheet
- [2]Magnesium glycinate (CID 84645): C4H8MgN2O4, MW 172.42. PubChem, NIH, 2026. database
- [3]Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial.. Nat Sci Sleep, 2025. RCT
- [4]Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection.. JPEN J Parenter Enteral Nutr, 1994. crossover-RCT
- [5]Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis.. BMC Complement Med Ther, 2021. meta-analysis
- [6]Magnesium for skeletal muscle cramps.. Cochrane Database Syst Rev, 2020. meta-analysis
- [7]Trimagnesium dicitrate (CID 6099959): C12H10Mg3O14, MW 451.12. PubChem, NIH, 2026. database
- [8]Magnesium bioavailability from magnesium citrate and magnesium oxide.. J Am Coll Nutr, 1990. PK-study
- [9]Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study.. Magnes Res, 2003. RCT
- [10]Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study.. Cephalalgia, 1996. RCT
- [11]Magnesium L-threonate (CID 45489777): C8H14MgO10, MW 294.50. PubChem, NIH, 2026. database
- [12]Enhancement of learning and memory by elevating brain magnesium.. Neuron, 2010. animal-study
- [13]Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial.. Sleep Med X, 2024. RCT
- [14]The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial.. Front Nutr, 2025. RCT
- [15]Magnesium malate (CID 164748): C4H4MgO5, MW 156.38. PubChem, NIH, 2026. database
- [16]Magnesium taurate (CID 13343447): C4H12MgN2O6S2, MW 272.6. PubChem, NIH, 2026. database
- [17]Magnesium oxide (CID 14792): MgO, MW 40.305. PubChem, NIH, 2026. database
- [18]Bioavailability of US commercial magnesium preparations.. Magnes Res, 2001. PK-study
- [19]FDA Drug Safety Communication: Low magnesium levels can be associated with long-term use of proton pump inhibitor drugs (PPIs). U.S. Food and Drug Administration, 2011. safety-communication
- [20]Inhibitory effects of zinc on magnesium balance and magnesium absorption in man.. J Am Coll Nutr, 1994. PK-study
- [21]The Effects of Magnesium Supplementation on Subjective Anxiety and Stress-A Systematic Review.. Nutrients, 2017. systematic-review
- [22]Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials.. Hypertension, 2016. meta-analysis
- [23]Effect of magnesium supplementation on glucose metabolism in people with or at risk of diabetes: a systematic review and meta-analysis of double-blind randomized controlled trials.. Eur J Clin Nutr, 2016. meta-analysis
- [24]Evidence-based guideline update: NSAIDs and other complementary treatments for episodic migraine prevention in adults (American Academy of Neurology and American Headache Society).. Neurology, 2012. guideline
- [25]Effects of Intravenous and Oral Magnesium on Reducing Migraine: A Meta-analysis of Randomized Controlled Trials.. Pain Physician, 2016. meta-analysis
- [26]Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling. U.S. Food and Drug Administration, 2005. guideline
What changed
- Added blood pressure, blood sugar, migraine and anxiety evidence rows; L-threonate, malate and taurate in the form comparison; RDA/UL table by age and sex; dose math; time to effect; kidney safety; food sources; label guide; cost-per-dose method; labelled analysis panel; three FAQs.
- First published.