Doctor's Best Brain Magnesium with Magtein® 90 Veggie Caps features the only form of magnesium shown in pre-clinical research to reliably cross the blood-brain barrier and increase brain magnesium levels. Developed by researchers at MIT, Magtein® (magnesium L-threonate) enhances synaptic density and plasticity in regions of the brain associated with learning and memory. In human clinical trials, Magtein® supplementation significantly improved overall cognitive ability scores after 12 weeks.*

• Magtein® — patented Mg L-threonate clinically shown to raise brain Mg*
• Supports synaptic density and plasticity for memory and learning*
• Improves cognitive performance scores in clinical research*
• Supports mental clarity, focus, and healthy brain ageing*
• Non-GMO | Gluten Free | 90 veggie capsules

Suggested Use: As a dietary supplement, take 3 capsules daily. Starting dose: 1 capsule per day, gradually increasing over 1–2 weeks.

Frequently Asked Questions

Why can't regular magnesium supplements raise brain magnesium levels?

The brain is protected by the blood-brain barrier (BBB), which tightly controls which substances can enter. Most forms of magnesium (oxide, citrate, glycinate, etc.) do not effectively cross the BBB in meaningful amounts. Magtein® (magnesium L-threonate) was specifically engineered with the threonate carrier molecule, which enables efficient transport across the BBB, resulting in significantly higher brain magnesium concentrations compared to other forms.*

What does increased brain magnesium actually do?

Magnesium in the brain plays a critical role in regulating NMDA receptor activity — a key mechanism in synaptic plasticity and long-term potentiation, which are the cellular processes underlying learning and memory. Higher brain magnesium levels are associated with greater synaptic density (more connections between neurons), faster learning, and better working memory. Magtein® studies in animals showed restored youthful synaptic density even in aged subjects.*

What is the recommended dose and is there a ramp-up period?

The standard dose is 3 capsules daily (providing ~2g of magnesium L-threonate). Doctor's Best recommends starting with 1 capsule per day and gradually increasing to 3 over 1–2 weeks to allow the body to adjust and minimise the mild digestive effects some people experience when starting magnesium supplementation.*

Can Brain Magnesium be taken with other cognitive supplements?

Yes. Magtein® pairs well with phosphatidylserine, acetyl-L-carnitine, and Lion's Mane mushroom as part of a comprehensive cognitive support stack. It also complements omega-3 DHA, which supports brain cell membrane integrity. Avoid taking very late at night initially as increased magnesium can sometimes promote sleep onset.*