Magnesium Glycinate vs Magnesium Citrate
Both are well-absorbed forms of magnesium. The practical differences are how they feel on your stomach, and what each one has actually been tested for.
Quick Summary
Both forms are well absorbed. Glycinate is usually gentler. Citrate is more likely to loosen stools. Neither is a sleep medicine.
Glycinate vs citrate
| Feature | Magnesium glycinate | Magnesium citrate |
|---|---|---|
| Bound to | Glycine, an amino acid | Citric acid |
| Absorption | Good. Few head-to-head trials versus citrate. | Good. More bioavailable than oxide in a randomized study. |
| Stomach | Usually gentler | More likely to loosen stools at higher doses |
| Studied for | Sleep quality in poor sleepers. The effect was small. | Raising magnesium status. Often used when regularity is the goal. |
There is no large trial that compares glycinate and citrate for sleep, mood, or muscle outcomes. Tolerance is the best-supported reason to pick one.
What the sleep research shows
Schuster and colleagues randomized 155 adults aged 18 to 65 with self-reported poor sleep to 250 mg elemental magnesium as bisglycinate or placebo for 4 weeks (Nature and Science of Sleep, 2025, PMC12412596). Insomnia Severity Index scores fell 3.9 points with magnesium and 2.3 with placebo (p=0.049). The effect size was small (Cohen's d=0.2). People with lower dietary magnesium may have responded more.
Each capsule was 893 mg of magnesium bisglycinate: 125 mg of magnesium and 761.5 mg of glycine. The daily dose was 250 mg of magnesium and 1,523 mg of glycine. The sleep change cannot be credited to magnesium alone.
A meta-analysis of 3 trials in older adults (151 people) found they fell asleep about 17 minutes faster than with placebo. Total sleep time did not differ significantly, and the evidence quality was low to very low (Mah and Pitre, 2021, PMC8053283).
Side effects and who should be careful
Diarrhea, nausea, and cramping are the main side effects of too much supplemental magnesium. The NIH upper limit for supplemental magnesium is 350 mg a day for adults. Food sources do not count toward that limit.
Ask your doctor first if you have kidney disease. Also ask if you take tetracycline or quinolone antibiotics, bisphosphonates, or diuretics, because spacing and dose matter.
Real labels, October 21, 2026
| Feature | What the label states | Price |
|---|---|---|
| Nature Made glycinate | 200 mg per serving, 2 capsules | $21.99 / 60 capsules |
| Carlyle glycinate gummies | 22 mg magnesium from 200 mg magnesium glycinate, per serving | $10.79 / 60 gummies |
| Micro Ingredients glycinate | 500 mg elemental per serving (3 capsules, 40 servings). Above the 350 mg supplemental limit. | $19.99 / 120 capsules |
| Nature's Answer glycinate | 360 mg of magnesium per serving. Capsules per serving not stated. Above 350 mg if taken as one serving. | $25.99 / 90 capsules |
| Nutricost glycinate | 210 mg from bisglycinate, 3 capsules, 30 servings in the 90-count | $11.97 / 90 capsules |
| Double Wood glycinate | Elemental milligrams not in the description. NSF Contents Certified to NSF/ANSI 173. Not NSF Certified for Sport. | $19.95 |
| Nature Made citrate | 250 mg per serving, 2 softgels | $14.19 / 60 |
| Double Wood citrate | 800 mg magnesium citrate, yielding 112 mg elemental magnesium | $19.95 |
Who this is for
Glycinate may suit
- ✓Citrate upsets your stomach, or you want an evening routine and you accept a small sleep effect.
Citrate may suit, or ask first
- ×You also want help with regularity, or you want a cheaper well-absorbed form.
- ×Kidney disease, or you take certain antibiotics or osteoporosis drugs. Ask first, and keep supplemental magnesium at or below 350 mg unless a clinician says otherwise.
Our verdict
Both forms are well absorbed. Glycinate is gentler, and citrate is more likely to loosen stools. The best sleep trial showed a small effect and also delivered about 1.5 grams of glycine. Compare elemental milligrams, and stay at or below 350 mg a day from supplements unless your clinician says otherwise.
Related guides
Sources
How we checked
On October 21, 2026, we re-opened the Schuster trial (155 adults, 250 mg elemental, ISI −3.9 vs −2.3, d=0.2, 1,523 mg glycine) and the NIH ODS professional fact sheet (supplemental upper limit 350 mg for adults).
The same day we checked Nature Made glycinate and citrate, Carlyle (22 mg from 200 mg glycinate), Micro Ingredients (500 mg elemental, 3 capsules, 40 servings, $19.99), Nature's Answer (360 mg of magnesium, $25.99 / 90), Nutricost (210 mg per 3 capsules, $11.97 / 90), and both Double Wood products. Double Wood glycinate did not state elemental milligrams. Its NSF line is Contents Certified to NSF/ANSI 173, which we are not calling Certified for Sport.
Walker 2003 and Mah and Pitre 2021 are cited from the published record. We did not re-download those PDFs in this pass.
Frequently Asked Questions
Glycinate is the form in the newest sleep trial, which found a small improvement in insomnia scores. No trial has compared it head to head with citrate. The capsules also contained 1,523 mg of glycine.
Citrate is more likely to have a laxative effect at higher doses. Glycinate tends to be gentler.
Only if your total supplemental magnesium stays at or below 350 mg a day, unless a clinician advises more.
It helps people with low intake meet magnesium needs, often with fewer stomach side effects than oxide. One trial showed a modest benefit for self-reported sleep.
Labels we opened ranged from 22 mg to 500 mg elemental. The adult upper limit from supplements is 350 mg a day.
The sleep trial used a daily dose. Take it with food if your stomach is sensitive.
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. Evident does not sell any of these products and uses no affiliate links.