Magnesium Glycinate vs Bisglycinate: 3 Honest Differences from a Pharmacist

Written by Josef Saleh, MPharm, Licensed Pharmacist

Magnesium glycinate vs bisglycinate is a comparison that confuses a lot of people. The names are almost identical. The products look the same. You might wonder if there is any real difference or if it is just marketing. As a pharmacist, I get this question often enough that it deserves a clear, honest answer.

This article will explain what these two forms actually are, whether one is better absorbed than the other, which one is gentler on the stomach, and how to choose between them without falling for labels that mean very little.

1. Magnesium Glycinate vs Bisglycinate: What Is Magnesium Glycinate

Magnesium glycinate is a chelated form of magnesium. Chelated means the magnesium atom is bound to another molecule to protect it and help it pass through the intestinal wall. In this case, the other molecule is glycine, an amino acid that functions as an inhibitory neurotransmitter in the brain.

Glycine has its own calming properties. It helps lower core body temperature at night, which is a signal the body uses to initiate sleep. It also acts on glycine receptors in the brainstem and spinal cord, where it dampens excitatory signals (1). This combination of magnesium and glycine is why this form has developed a reputation as the sleep magnesium.

Technically, magnesium glycinate refers to one magnesium atom bound to one glycine molecule. But in practice, most products sold as magnesium glycinate actually contain magnesium bisglycinate. The terms are used interchangeably by almost every supplement manufacturer. I will explain why shortly.

2. What is magnesium bisglycinate

Magnesium bisglycinate is the same magnesium atom bound to two glycine molecules instead of one. The prefix bis means two. The additional glycine molecule provides extra protection for the magnesium as it travels through the digestive tract.

This is important because free magnesium ions in the gut attract water. That water pull is what causes the laxative effect seen with magnesium citrate and magnesium oxide. By fully chelating the magnesium with two glycine molecules, bisglycinate is the most protected form of magnesium available. It is the least likely to cause any digestive side effects.

Here is the honest truth that most articles do not explain clearly. Almost every product on the market labeled as magnesium glycinate is actually magnesium bisglycinate. The manufacturers use the terms interchangeably because the difference is technical and the consumer knows glycinate as the sleep magnesium. If you read the supplement facts panel and see magnesium bisglycinate chelate or TRAACS magnesium bisglycinate, that is the fully reacted bisglycinate form.

TRAACS is a trademarked form of magnesium bisglycinate manufactured by Albion Minerals. It is one of the most researched and trusted chelated mineral brands. When you see TRAACS on a label, you are getting magnesium bisglycinate that has been produced to pharmaceutical-grade standards.

3. The absorption question

The question everyone asks is whether bisglycinate is better absorbed than glycinate. The answer is that they are essentially the same, with a slight theoretical edge for bisglycinate.

A 2021 systematic review of magnesium bioavailability found that organic forms of magnesium, which includes both glycinate and bisglycinate, are significantly more bioavailable than inorganic forms like magnesium oxide (2). The review did not find a meaningful absorption difference between the various organic chelates.

The theoretical advantage of bisglycinate is that the two glycine molecules provide more complete protection of the magnesium ion. This means less interaction with other compounds in the gut that could form insoluble complexes. But in practice, both forms are absorbed through the amino acid transport pathway, which is efficient and does not depend on stomach acidity.

A 2019 study on magnesium compounds found that amino acid-bound magnesium compounds demonstrated dose-dependent absorption profiles with good bioavailability (3). The study did not find significant differences between the various amino acid chelates.

The bottom line is that both glycinate and bisglycinate are in the top tier of magnesium absorption. The difference between them is far smaller than the difference between either of them and magnesium oxide. I have written a comparison of magnesium glycinate and citrate if you are deciding between those two very different forms.

4. Side effects and tolerability

Both glycinate and bisglycinate are extremely gentle on the stomach. They are the best-tolerated forms of magnesium available. This is because the glycine chelation prevents free magnesium ions from accumulating in the gut and drawing water into the bowel.

Magnesium bisglycinate has a slight edge in tolerability. The second glycine molecule provides additional protection, which means even less chance of any digestive side effect. For someone who has tried multiple forms of magnesium and experienced loose stools or bloating with each one, bisglycinate is usually the form that finally works.

In clinical practice, I have seen patients who could not tolerate any magnesium supplement until they tried bisglycinate. This is not because bisglycinate is dramatically different from glycinate. It is because most products labeled as glycinate are already bisglycinate, and the bisglycinate they finally tried was simply a well-manufactured product.

If you have a sensitive stomach, or if magnesium citrate or oxide has sent you running to the bathroom, either glycinate or bisglycinate will be a much gentler experience. The difference between the two is negligible for most people.

5. Which one is better for sleep and anxiety

Both forms are excellent for sleep and anxiety because the active components are the same. Magnesium supports GABA receptor function and helps regulate the body’s stress response system. Glycine provides additional calming effects by acting as an inhibitory neurotransmitter and lowering core body temperature (1).

A 2025 randomized, placebo-controlled trial examined magnesium bisglycinate supplementation in adults reporting poor sleep (4). The study found that magnesium bisglycinate modestly improved insomnia severity compared to placebo. Most of the benefit was seen in people whose dietary magnesium intake was low at baseline.

For anxiety, a 2017 systematic review found that magnesium supplementation was associated with reductions in subjective anxiety, particularly in people vulnerable to stress (5). Most studies did not use bisglycinate specifically. The benefit appears to be linked to magnesium itself rather than the specific chelate.

If you are choosing between glycinate and bisglycinate for sleep, the honest answer is that either will work. The magnesium and glycine are the same. Choose based on tolerability and product quality, not on the label distinction.

6. Dosing and how to take them

The standard adult dose for sleep and general magnesium supplementation is 200 to 400 milligrams of elemental magnesium per day, taken in the evening about 30 to 60 minutes before bed. Start at 200 milligrams and increase gradually over a week or two.

Check the label carefully. Some products list the total weight of the magnesium glycinate or bisglycinate compound, which includes the glycine. You want the elemental magnesium amount. For example, a product might contain 1,000 milligrams of magnesium bisglycinate powder but provide only 100 milligrams of elemental magnesium per serving.

Take magnesium with water on an empty stomach for best absorption. Avoid taking it with food high in calcium or fat, which can compete for absorption pathways. If you take antibiotics, especially tetracyclines or fluoroquinolones, separate magnesium by at least two hours. These medications bind to magnesium in the gut and become less effective.

7. How to choose between them

The choice between magnesium glycinate and bisglycinate comes down to three practical considerations.

First, look at the label. If the product says magnesium bisglycinate or TRAACS magnesium bisglycinate, you are getting the fully chelated form with two glycine molecules. If it says magnesium glycinate, it is almost certainly still bisglycinate, just labeled for consumer recognition.

Second, prioritize product quality over the label distinction. Look for a manufacturer that provides third-party testing, transparent labeling, and the elemental magnesium amount clearly stated. A high-quality bisglycinate from a reputable brand is better than a poorly manufactured product labeled as glycinate.

Third, if you have an extremely sensitive stomach and have failed other forms of magnesium, bisglycinate is worth trying. The additional glycine molecule provides marginal but real additional protection. Most people will do equally well with either.

For most people, the choice between glycinate and bisglycinate is a distinction without a difference. Both are well-absorbed, gentle forms of magnesium that are excellent for sleep and stress. If you find a product you tolerate well at a fair price, you have found the right one.

If you want to learn more about how these forms compare to others, I have written about the differences between magnesium glycinate and citrate, as well as a guide to powdered magnesium glycinate for those who prefer a flexible dose.

Written by Josef Saleh, MPharm, Licensed Pharmacist. This article is for informational purposes only and does not constitute medical advice. Always consult your pharmacist or doctor before starting any new supplement.

References

1. Bannai M, Kawai N. New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. J Pharmacol Sci. 2012;118(2):145-148.
2. Blancquaert L, Vervaet C, Derave W. Bioavailability of magnesium food supplements: A systematic review. Nutrients. 2021;13(4):1136.
3. Ates M, Kizildag S, Yuksel O, et al. Dose-Dependent Absorption Profile of Different Magnesium Compounds. Biol Trace Elem Res. 2019;192:244-251.
4. Scholey A, et al. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nat Sci Sleep. 2025;17:1125-1138.
5. Boyle NB, Lawton C, Dye L. The Effects of Magnesium Supplementation on Subjective Anxiety and Stress: A Systematic Review. Nutrients. 2017;9(5):429.

This post contains affiliate links. If you purchase through my links I may earn a small commission at no extra cost to you.