Capsules · 120 capsules · 60 servings · $1.21/serving
Magtein Magnesium L-Threonate from Metagenics delivers magnesium in the L-threonate form, a chelated compound studied for its ability to cross the blood-brain barrier more readily than conventional magnesium salts. It supports cognitive function, memory, and overall neurological health, and is particularly relevant for adults focused on brain-specific magnesium status.
Why It's Worth Considering: Metagenics uses the patented Magtein® form of magnesium L-threonate, the specific compound featured in neuroscience research on synaptic density and cognitive support, a meaningful distinction from standard magnesium supplements.
| Feature | Glycinate | Citrate | Oxide | L-Threonate | Taurate |
|---|---|---|---|---|---|
| Bioavailability | High (chelated) | Moderate-High | Low (4-5%) | Moderate | Moderate-High |
| Best For | Sleep, anxiety, cramps | Constipation, general | Budget (low absorption) | Cognitive function | Heart health |
| GI Tolerance | Excellent | Moderate | Poor (laxative) | Good | Good |
| Laxative Effect | None | Mild–Moderate | Strong | None | None |
| Evidence | Strong | Strong | Weak | Emerging | Moderate |
Magnesium glycinate (bisglycinate chelate) is widely considered the best form for sleep, anxiety, and muscle cramps due to high bioavailability and zero laxative effect. Citrate is better for constipation. Threonate may be superior for cognitive function as it crosses the blood-brain barrier. Oxide has only 4-5% absorption and is primarily a laxative.
No. Unlike magnesium citrate and oxide which draw water into the intestines (osmotic laxative effect), glycinate is chelated and absorbed through a different pathway that does not affect GI motility. It is the most GI-friendly magnesium form available.
Take 1-2 hours before bed for sleep benefits. The glycine component promotes relaxation via GABA receptor activity. For general supplementation, any time works — glycinate does not require food for absorption.
Standard blood tests (serum magnesium) are unreliable — only 1% of body magnesium is in the blood. Signs include muscle cramps, poor sleep, anxiety, eye twitches, chocolate cravings, and headaches. Since 80%+ of adults are suboptimal, supplementation is generally recommended.
Yes, but separate from zinc, calcium, and iron by 2+ hours (they compete for absorption). Magnesium pairs well with Vitamin D3, K2, and B6 taken together.
The RDA is 310-420mg/day for adults. Most functional medicine practitioners recommend 400-600mg for therapeutic benefit. Start with the product's recommended dose and adjust based on response.
† 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.
