What is the difference between glycinate and bisglycinate?

December 6, 2025 •

4 min read

Over 50% of the US population may be deficient in magnesium, leading many to seek supplements like magnesium glycinate or bisglycinate. While many supplement labels use these terms interchangeably, there is a subtle but important distinction between glycinate and bisglycinate that can affect absorption and effectiveness. Understanding this difference is key to choosing the right mineral supplement for your health needs.

Quick Summary

Glycinate and bisglycinate are often used interchangeably, but bisglycinate is the more chemically accurate term, indicating two glycine molecules bound to a mineral ion. This full chelation typically ensures superior stability and absorption, while 'glycinate' can sometimes refer to less potent or partially-reacted forms.

Key Points

Terminology vs. Chemistry: While often used interchangeably, 'bisglycinate' is the chemically precise term for a mineral bound to two glycine molecules, whereas 'glycinate' can be a more generic, less specific marketing term.
Superior Absorption: A fully chelated bisglycinate form generally offers superior absorption and bioavailability due to its high stability within the digestive system.
Reduced Digestive Issues: The double chelation of bisglycinate results in a very stable and buffered compound that is less likely to cause the gastrointestinal discomfort or laxative effects associated with other mineral forms.
Ensure Product Purity: To ensure you are receiving the fully chelated compound, look for the term 'bisglycinate' or check the label for confirmation that the product is 'fully reacted' or 'chelated'.
Informed Supplementation: Understanding the difference helps you make a more informed choice, especially for sensitive minerals like magnesium, iron, and zinc where bioavailability is a key factor for effectiveness.

Understanding Chelated Minerals

Before diving into the specifics of glycinate versus bisglycinate, it's crucial to understand the concept of chelated minerals. Chelation is a chemical process where a mineral is bound to an organic compound, typically an amino acid, to enhance its absorption in the body. The body can absorb minerals in their free, inorganic state, but this process can be inefficient and prone to interference from other dietary compounds. Chelation essentially protects the mineral as it passes through the digestive tract, ensuring it reaches the small intestine for better uptake. Glycine, a calming amino acid, is a popular chelating agent for minerals like magnesium and zinc due to its mild nature and ability to form stable complexes.

The Chemical Distinction: Glycinate vs. Bisglycinate

At the core of the difference between glycinate and bisglycinate lies a precise chemical detail concerning the number of glycine molecules attached to the mineral. The prefix 'bis-' means 'two', and this is the fundamental clue.

Glycinate: The Common Term

The term 'glycinate' is a broader, more general name used in marketing and is more user-friendly. However, on a chemical level, it doesn't always specify the exact binding ratio. Some less expensive or lower-quality supplements labeled as 'magnesium glycinate' may be a mixture of magnesium oxide or other cheaper forms combined with glycine, or they may be only partially chelated with a single glycine molecule. This variability means that the stability and bioavailability can differ significantly between brands.

Bisglycinate: The Precise Term

'Bisglycinate' is the more chemically accurate term that clarifies the compound's structure: one mineral ion is bonded to two glycine molecules. This full, double chelation creates a highly stable and buffered complex. This structural difference has practical benefits for the end-user, including superior stability in the stomach's acidic environment, which prevents the mineral from being neutralized before it can be absorbed. As a result, fully chelated bisglycinate is less likely to cause digestive upset or have a laxative effect, common side effects of less stable magnesium forms like magnesium oxide.

Comparison Table: Glycinate vs. Bisglycinate


Feature	Glycinate (as a general term)	Bisglycinate (precise chemical term)
Chemical Structure	Can be one or two glycine molecules, or a mix of various compounds.	One mineral ion bonded to two glycine molecules.
Bioavailability	Good, but potentially variable depending on the brand and chelation quality.	Superior. The double chelation ensures higher stability and absorption rate.
Digestive Impact	Generally gentle on the stomach compared to non-chelated minerals.	Often even gentler on sensitive digestive systems due to superior stability.
Purity & Consistency	Can vary. A product labeled 'glycinate' might be a blended or partially chelated form.	More consistent and often purer, representing the fully chelated compound.
Therapeutic Benefits	Effective for relaxation, sleep, and anxiety relief due to the calming effects of glycine.	Potentially more effective for addressing severe deficiencies or muscle recovery due to higher absorption.
Cost	Typically more affordable, but this can reflect a less potent or pure product.	Usually slightly more expensive due to the more complete chelation process.

The Impact of Chelation on Different Minerals

This glycinate versus bisglycinate distinction is particularly relevant for minerals known for digestive sensitivity or those that compete for absorption with other compounds. For example:

Magnesium: Magnesium bisglycinate is often the gold standard for supplementation, especially for those seeking relaxation or sensitive to other forms like citrate or oxide. The bisglycinate form offers the calming benefits of glycine alongside superior, non-laxative absorption.
Iron: The chelated bisglycinate form of iron (ferrous bisglycinate) is associated with higher bioavailability and significantly fewer gastrointestinal side effects like constipation compared to ferrous sulfate. This makes it a gentler and more effective option for treating iron deficiency anemia.
Zinc: Zinc bisglycinate has been shown to be substantially more bioavailable than other forms like zinc gluconate or zinc oxide. The chelated structure protects the zinc from dietary inhibitors and allows for efficient absorption through specialized pathways in the gut.

How to Choose the Right Supplement

When selecting a supplement, the label is your most important tool. To ensure you are getting the higher-quality, fully chelated form, look specifically for the term 'bisglycinate'. If the label simply says 'glycinate', check the supplement facts panel and the manufacturer's description for confirmation that it is a 'fully reacted' or 'fully chelated' bisglycinate. Some reputable brands will even specify 'magnesium bisglycinate chelate'. Opting for established, trusted brands with transparent labeling can help ensure you receive the full benefits of a high-quality chelated mineral.

Conclusion: Making an Informed Choice

The distinction between glycinate and bisglycinate is more than just semantics; it represents a significant difference in chemical structure that impacts a mineral's stability, bioavailability, and overall effectiveness. While the term 'glycinate' is a common and widely understood marketing term, 'bisglycinate' is the precise chemical name for the superior, fully-chelated form. For those seeking maximum absorption, minimal digestive side effects, and reliable therapeutic results—especially with minerals like magnesium, iron, and zinc—choosing a supplement that explicitly states 'bisglycinate' is the most informed decision. By understanding this nuance, consumers can make better choices for their health and ensure they are getting the most value from their supplements.

Authoritative Link

For more information on the bioavailability of chelated minerals, the National Institutes of Health (NIH) provides a comprehensive database of scientific research and chemical information.

Frequently Asked Questions

In most cases, yes, they refer to the same compound, which is a magnesium ion chelated with two glycine molecules. However, some products labeled simply 'glycinate' may be a mix of compounds or less pure, so 'bisglycinate' is the more specific and reliable term for a fully chelated product.

Bisglycinate is considered superior for absorption. The binding of a mineral to two glycine molecules in the bisglycinate form creates a more stable compound that is better protected during digestion, leading to higher and more reliable bioavailability.

The double chelation in bisglycinate creates a highly stable complex that prevents the mineral from being released too quickly or interacting with stomach acids. This stability minimizes irritation to the digestive tract and reduces the risk of side effects like diarrhea, which are common with less stable forms.

Not always. While the term generally implies chelation, some lower-cost supplements labeled 'glycinate' may be a simple blend of a mineral salt and glycine, or only partially chelated, leading to variable absorption rates.

Yes, for zinc, the terms are generally considered synonymous and refer to the same compound where a zinc atom is bound to two glycine molecules. Zinc bisglycinate has been shown to be one of the most bioavailable forms of zinc.

For optimal absorption and product consistency, choosing a supplement specifically labeled 'bisglycinate' is the best practice. This ensures you are getting a fully chelated form, especially if you have sensitive digestion or are addressing a specific deficiency.

Beyond acting as a chelating agent, glycine is an amino acid known for its calming properties. It acts as an inhibitory neurotransmitter, which promotes relaxation and can help improve sleep quality.