What magnesium glycinate is
Magnesium glycinate (also sold as bisglycinate) is magnesium bound to glycine, an amino acid. Magnesium helps run more than 300 enzyme systems, including ones for muscle and nerve function, protein building, blood sugar control and blood pressure.
Adults need 310 to 420 mg a day from all sources, depending on age and sex. A national survey (NHANES 2013 to 2016) found 48% of Americans got less than the average requirement from food and drinks. Leafy greens, beans, nuts, seeds and whole grains are good food sources. Labels list elemental magnesium per serving; compare that number.
What the evidence shows
| Goal | Strength of evidence | What studies show |
|---|---|---|
| Low magnesium intake | Strong rationale | A supplement can close the gap when food falls short |
| Sleep | Modest | A 2025 glycinate trial found a small drop in insomnia scores versus placebo |
| Leg cramps in older adults | Weak (moderate certainty of little benefit) | A Cochrane review found magnesium unlikely to help in a meaningful way |
| Migraine | Moderate, for magnesium in general | The American Academy of Neurology and American Headache Society rate magnesium as probably effective at reducing how often migraines happen. The doses used usually exceed the upper limit, so only with a clinician's guidance |
| Blood pressure | Small effect | Trials show only a marginal drop |
| Blood sugar | Not enough evidence | The American Diabetes Association does not recommend it for glucose control |
Magnesium glycinate for sleep
In a 2025 trial in Germany, 155 adults who reported poor sleep took 250 mg of elemental magnesium as bisglycinate or a placebo for four weeks. Insomnia scores fell by 3.9 points with magnesium and 2.3 points with placebo. The authors called the effect small and modest. Other measures, like stress and mood, did not differ, and all results were self-reported.
So it may help a little, especially for mild sleep complaints. If sleep is poor most nights, causes like sleep apnea or restless legs are worth looking at with a clinician.
Magnesium for muscle cramps
A 2020 Cochrane review found it is unlikely that magnesium gives older adults meaningful relief from ordinary cramps with no clear cause (moderate-certainty evidence). For cramps in pregnancy the evidence was very uncertain, and there were no good studies on exercise cramps. Muscle cramps can be a sign of true magnesium deficiency, which is uncommon in healthy people and usually tied to a health condition, alcohol use or certain medicines.
Who should be careful
- Kidney disease. Kidneys clear extra magnesium. If yours don't work well, it can build up. Ask your clinician before taking any form.
- Osteoporosis drugs (oral bisphosphonates). Take magnesium at least 2 hours before or after them.
- Tetracycline and quinolone antibiotics. Take these at least 2 hours before or 4 to 6 hours after magnesium.
- Diuretics and acid reducers (PPIs). These can change your magnesium level, so long-term users may want it checked.
- Pregnancy and breastfeeding. Ask your clinician before starting any supplement.
The adult upper limit for magnesium from supplements and medicines is 350 mg a day; food doesn't count. See can you take too much magnesium and magnesium glycinate vs citrate.
Stop magnesium and get care right away if you feel very weak, dizzy or faint, or notice an irregular heartbeat or trouble breathing.
What it costs
With Gabriel Core or Plus, magnesium glycinate, 180 capsules, is $31.33 (list price $56.99). Not sure you need it? Ask Gabriel free about your diet, medicines and any lab results first.
Common questions
What is magnesium glycinate good for?
Its clearest use is getting enough magnesium when food falls short. Evidence for better sleep is modest, and evidence for leg cramps is weak.
Does magnesium glycinate help you sleep?
It may help a little. A 2025 trial in adults with poor sleep found a small improvement in insomnia scores compared with placebo after four weeks.
Does magnesium glycinate help with leg cramps?
Probably not much for ordinary cramps with no clear cause in older adults, according to a 2020 Cochrane review. Evidence in pregnancy is very uncertain.
What are the side effects of magnesium glycinate?
No serious side effects were reported in the 2025 trial. Too much supplemental magnesium can cause diarrhea, nausea and cramping, so stay at or under 350 mg a day unless a clinician advises more.
Who should not take magnesium glycinate?
People with kidney disease should ask a clinician first. If you take bisphosphonates or certain antibiotics, ask a pharmacist how to space your doses.
Sources
- Magnesium: Fact Sheet for Health Professionals NIH Office of Dietary Supplements
- Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial (Schuster et al., 2025) Nature and Science of Sleep (Dove Medical Press)
- Magnesium for skeletal muscle cramps (Garrison et al., 2020) Cochrane
This guide is general information, not medical advice. It does not replace a visit with a licensed clinician. Gabriel membership is not health insurance.