Magnesium Glycinate vs Magnesium L-Threonate: Which Is Better?
Last updated: August 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy
Glycinate for general use, sleep and repletion — it is cheaper, better tolerated and supplies more elemental magnesium per capsule. Threonate is marketed for brain penetration on the basis of rodent work and one small human trial, and it costs several times more.
Key takeaways
- Threonate's brain-penetration claim rests on rodent studies and thin human data.
- Threonate is low in elemental magnesium — around 8% — so more capsules are needed.
- Glycinate does the ordinary job well at a fraction of the price.
What threonate claims
Magnesium L-threonate was developed on the finding that it raised brain magnesium in rats more than other forms. The threonate moiety is proposed to help cross the blood-brain barrier. A small human trial reported cognitive improvements in older adults. That is a genuine line of research and it is early, small and largely conducted by parties with a commercial interest.
The practical drawbacks
Threonate is roughly 8% elemental magnesium, one of the lowest of any form, so reaching 200–400 mg elemental takes a lot of capsules. It is typically several times the price of glycinate per unit of magnesium. If your goal is correcting magnesium status, you are paying a large premium for a delivery claim that has not been well demonstrated in humans.
When each makes sense
Glycinate for sleep, cramps, general repletion and anyone who wants magnesium without bowel effects — which is most people. Threonate if cognitive benefit specifically is what you are after and you accept the evidence is preliminary. Taking glycinate for magnesium status and judging the cognitive claim separately is the more rational split.
Key ingredients to understand
The ingredients most relevant to this question, with what the evidence actually supports:
- Magnesium Glycinate — Magnesium glycinate (magnesium bound to glycine) is a gentle, well-absorbed form popular for sleep and relaxation, and easier on the stomach…
- Magnesium — Magnesium is an essential mineral involved in hundreds of body processes, including nerve and muscle function, energy and blood-sugar control.…
- Glycine — Glycine is the smallest amino acid and a building block the body uses for collagen and many other roles. As a supplement it is taken mainly as a…
- L-Theanine — L-theanine is an amino acid from tea that promotes a state of calm alertness without sedation. It has modest but reasonably consistent evidence…
Frequently asked questions
Does threonate actually reach the brain better in humans?
That has not been well demonstrated. The strong data are in rats.
Can I take both?
Yes, but add up the total elemental magnesium and stay near 350 mg supplemental.
Which is better for anxiety?
Neither has strong trial evidence. Glycinate is the cheaper thing to try first.
Related on FactoWiki
- All health answers
- Ingredient evidence guides
- Magnesium Glycinate — ingredient guide
- Magnesium — ingredient guide
- How we review
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