The magnesium glycinate vs citrate choice comes down to what the magnesium is bound to. Glycinate is magnesium bound to the amino acid glycine and is the form tested for sleep: 250 mg a day slightly eased poor sleep in a 2025 trial. Citrate is magnesium bound to citric acid. It dissolves well, gave the highest blood levels in a 60-day absorption trial, and draws water into the bowel, which is why it is used for regularity. No trial has compared the two forms head to head.
Below you'll find how the two compare and what the studies found for each. We also cover how well each is absorbed, the doses studied and the upper limit, side effects, the other common forms, and the magnesium glycinate products we have graded. Our magnesium page covers every form and every magnesium product in our catalog.
Quick Answer: Magnesium Glycinate vs Citrate Side by Side
This table sets out what the human studies found for each form.
| Magnesium glycinate | Magnesium citrate | |
|---|---|---|
| What it is | Magnesium bound to glycine, an amino acid (also sold as bisglycinate or glycinate chelate) | Magnesium bound to citric acid |
| Most studied for | Sleep | Absorption and regularity |
| Sleep | Eased poor sleep slightly more than placebo in 155 adults over 4 weeks | No better than placebo in 100 adults over 7 weeks |
| Absorption | Better than magnesium oxide in people who absorb poorly; never tested against citrate | Highest blood levels of three forms in a 60-day trial of 46 adults |
| Effect on digestion | Gentle; better tolerated than oxide in a small trial | Draws water into the bowel and softens stools |
| Magnesium a day in the trials | 250 mg | 300 to 320 mg |
| Strength of evidence | Early for sleep: one trial, small effect | Moderate for absorption; no effect for sleep |
Not sure which form you need? Get a protocol that picks it for you.
Magnesium Glycinate: Studied for Sleep and Calm
In the largest trial of this form, 155 adults aged 18 to 65 who slept poorly took 250 mg of magnesium a day as bisglycinate, or a placebo. After four weeks, their scores on a standard sleep-problem questionnaire had fallen by 3.9 points against 2.3 on placebo. The difference was small and only just statistically significant. People who got little magnesium from food seemed to gain the most (Schuster 2025).
Other sleep trials used other forms of magnesium. Pooling three small trials in 151 older adults, magnesium helped people fall asleep about 17 minutes sooner than placebo, but the authors rated the evidence low to very low in quality (Mah 2021). In one of those trials, 46 older adults taking 500 mg of magnesium a day for eight weeks had better sleep scores and sleep efficiency than on placebo (Abbasi 2012).
Glycine itself is studied for sleep: 3 g taken before bed eased daytime fatigue after nights of short sleep (Bannai 2012). A 200 mg dose of magnesium as glycinate carries a little over 1 g of glycine, less than in those studies.
Calm. Glycinate is often sold for calm, but it hasn't been tested for that on its own. A review of 18 studies of magnesium in people prone to anxiety found less anxiety in about half of them, and judged the quality of the evidence poor (Boyle 2017). Our stress and calm goal page and sleep goal page rank the ingredients with the strongest evidence for each.
Magnesium Citrate: Studied for Absorption and Regularity
Citrate dissolves well. In lab tests it was 55% soluble even in plain water, while magnesium oxide barely dissolved. In volunteers, the magnesium passed in urine after a dose rose far more after citrate than after oxide (Lindberg 1990). That urine figure is a sign of how much was absorbed.
In a 60-day trial, 46 healthy adults took 300 mg of magnesium a day. Citrate and an amino-acid chelate (the family glycinate belongs to) were both absorbed better than oxide, and citrate gave the highest blood magnesium of the three (Walker 2003).
Regularity. Citrate draws water into the bowel, which softens stools, and at high doses it goes into the bowel-cleansing drinks used before colon exams (Hookey 2016). The trials of daily magnesium for regularity used magnesium oxide. Across two such trials, 68% of people responded against 19% on control, with about 3.7 more bowel movements a week (van der Schoot 2023). We found no long-term trials of citrate itself for regularity. Our regularity goal page ranks the products by the evidence.
Sleep. In 100 adults over 51 who slept poorly, 320 mg of magnesium a day as citrate for seven weeks improved sleep scores no more than placebo; both groups improved (Nielsen 2010).
Absorption: What the Human Studies Show
No trial has compared glycinate with citrate directly. Glycinate was compared with oxide in 12 people who had lost part of the small bowel to surgery. Overall absorption was the same. But in the four who absorbed oxide worst, glycinate was absorbed twice as well (23.5% against 11.8%), and it was better tolerated (Schuette 1994).
The product can matter as much as the form. When 15 magnesium supplements were tested in the lab, how much of each dissolved varied widely. In 30 volunteers, the product that dissolved best raised blood magnesium far more than the one that dissolved worst (Blancquaert 2019).
Doses Studied, Timing and the Upper Limit
The trials above gave 250 mg of magnesium a day as glycinate and 300 to 320 mg as citrate. Those figures count the magnesium itself, not the weight of the compound. For example, Doctor's Best uses 2,000 mg of magnesium lysinate glycinate chelate to supply 200 mg of magnesium, so read the line on the label that says "Magnesium (as ...)".
The US upper limit for magnesium from supplements is 350 mg a day for adults, set because higher doses can cause diarrhea; magnesium from food doesn't count. Some researchers argue the limit is too low, since several trials found no more diarrhea at higher doses (Costello 2023). Our magnesium page lists the doses studied for every form. Our guide to safe upper limits shows how to add up magnesium across your stack.
No trial has compared morning with evening doses of either form. Glycinate taken for sleep is usually taken in the evening, and Nature Made's label, for one, says to take it with water and a meal to help absorption. Our guide to the best time to take your vitamins and supplements covers timing across your whole stack.
Side Effects, and Checking With Your Doctor if You Take Meds
Loose stools and stomach upset are the most common side effects of magnesium, and they become more likely as the dose rises. Citrate's pull of water into the bowel is the point if you take it for regularity, and a nuisance if you don't. Glycinate was better tolerated than oxide in the small trial above.
Magnesium leaves the body through the kidneys, so people whose kidneys don't work fully can build it up; ask your doctor before taking it. Magnesium can also bind some meds in the gut and stop them being absorbed, so if you take meds, ask your pharmacist how far apart to take them. The stack checker shows whether any of your supplements clash with each other or with your meds.
Other Forms in Brief: Threonate, Oxide and Malate
Magnesium L-threonate is sold for the brain and sleep. In 80 adults aged 35 to 55 with sleep problems, 1 g a day for 21 days improved deep and REM sleep scores on a sleep-tracking ring, along with daytime energy and mood ratings, compared with placebo (Hausenblas 2024).
Magnesium oxide packs the most magnesium into each pill but is poorly absorbed: in the 60-day trial it raised blood magnesium no more than placebo (Walker 2003). Yet it is the form shown to work for regularity in trials (van der Schoot 2023).
Magnesium malate is magnesium bound to malic acid. We found no human trials of it for sleep or regularity.
Our magnesium glycinate and magnesium citrate pages list the studies on each form. Our article on magnesium for sleep, stress and healthy aging covers the wider research.
The top-rated glycinate products
These are the four magnesium glycinate products people search for most. Each product page shows what is on the label, the human studies behind it and what reviewers report, and members see each product's grade. Costs are at the prices in our catalog.
| Product | Magnesium per serving | Serving | Cost per month |
|---|---|---|---|
| Pure Encapsulations Magnesium Glycinate | 120 mg | 1 capsule | $28 at 2 capsules a day |
| Thorne Magnesium Bisglycinate | 200 mg | 1 scoop of powder | $26 |
| Nature Made Magnesium Glycinate | 200 mg | 2 capsules | $12 |
| Doctor's Best High Absorption Magnesium Glycinate | 200 mg | 2 tablets | $5 |
Already taking magnesium? Check your stack for doubling up and timing.
Which Form Fits Your Stack
The right form depends on why you take magnesium, what else is in your stack and any meds. Rala, the AI behind Reverse Age Lab, counts the magnesium across every product you take and checks it against the upper limit and your meds. It then builds one daily protocol with the form, dose and timing that fit your goals. Start your personalized protocol.
Is this medical advice? No. This guide sets out the published research on magnesium glycinate and magnesium citrate; it is not a diagnosis, and Rala isn't a medical device or a clinician. Talk to your doctor before adding magnesium, especially if you take meds or your kidneys don't work fully.
Frequently Asked Questions
Which is better, magnesium glycinate or citrate?
It depends on what you take it for. Glycinate is the form tested for sleep, with a small benefit in one trial of 155 adults. Citrate is well absorbed and draws water into the bowel, which helps regularity. No trial has compared them head to head.
Can I take magnesium glycinate and citrate together?
You can, but add up the magnesium from both. The US upper limit for magnesium from supplements is 350 mg a day, and higher doses make loose stools more likely.
Which magnesium is best for sleep?
No form has strong evidence yet. Glycinate (250 mg of magnesium a day) and L-threonate (1 g a day) each improved sleep in one placebo-controlled trial, while citrate did no better than placebo in another. Pooled trials of magnesium in older adults found people fell asleep about 17 minutes sooner, from low-quality evidence.
When should I take magnesium glycinate?
No trial has compared times of day. Glycinate taken for sleep is usually taken in the evening, and some labels advise taking it with a meal to help absorption.
Sources
Schuster J, Cycelskij I, Lopresti A et al. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep, 2025. PubMed.
Mah J, Pitre T. Oral magnesium supplementation for poor sleep in older adults: a systematic review and meta-analysis. BMC Complementary Medicine and Therapies, 2021. PubMed.
Abbasi B, Kimiagar M, Sadeghniiat K et al. The effect of magnesium supplementation on poor sleep in older adults: a double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences, 2012. PubMed.
Bannai M, Kawai N, Ono K et al. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in Neurology, 2012. PubMed.
Boyle NB, Lawton C, Dye L. The effects of magnesium supplementation on subjective anxiety and stress: a systematic review. Nutrients, 2017. PubMed.
Lindberg JS, Zobitz MM, Poindexter JR et al. Magnesium bioavailability from magnesium citrate and magnesium oxide. Journal of the American College of Nutrition, 1990. PubMed.
Walker AF, Marakis G, Christie S et al. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research, 2003. PubMed.
Hookey L, Haimanot S, Marchut K et al. A randomized trial of low-volume oral laxative, enemas, and both for bowel preparation before flexible sigmoidoscopy. Clinical and Translational Gastroenterology, 2016. PubMed.
van der Schoot A, Creedon A, Whelan K et al. The effect of food, vitamin, or mineral supplements on regularity in adults: a systematic review and meta-analysis of randomized controlled trials. Neurogastroenterology and Motility, 2023. PubMed.
Nielsen FH, Johnson LK, Zeng H. Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep. Magnesium Research, 2010. PubMed.
Schuette SA, Lashner BA, Janghorbani M. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. Journal of Parenteral and Enteral Nutrition, 1994. PubMed.
Blancquaert L, Vervaet C, Derave W. Predicting and testing bioavailability of magnesium supplements. Nutrients, 2019. PubMed.
Costello R, Rosanoff A, Nielsen F et al. Perspective: call for re-evaluation of the tolerable upper intake level for magnesium supplementation in adults. Advances in Nutrition, 2023. PubMed.
Hausenblas HA, Lynch T, Hooper S et al. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial. Sleep Medicine: X, 2024. PubMed.
