---
product_id: 7194707
title: "Magtein Magnesium L-Threonate, 667mg, Supports Focus, Mood, Healthy Memory, Cognitive Function - 180 Capsules"
brand: "source naturals"
price: "¥19049"
currency: JPY
in_stock: true
reviews_count: 13
category: "Source Naturals"
url: https://www.desertcart.jp/products/7194707-magtein-magnesium-l-threonate-667mg-supports-focus-mood-healthy-memory
store_origin: JP
region: Japan
---

# Enhances focus, mood & energy 667mg Magnesium L-Threonate for brain boost Crosses blood-brain barrier for max effect Magtein Magnesium L-Threonate, 667mg, Supports Focus, Mood, Healthy Memory, Cognitive Function - 180 Capsules

**Brand:** source naturals
**Price:** ¥19049
**Availability:** ✅ In Stock

## Summary

> 🧩 Unlock your brain’s full potential — because your mind deserves the best.

## Quick Answers

- **What is this?** Magtein Magnesium L-Threonate, 667mg, Supports Focus, Mood, Healthy Memory, Cognitive Function - 180 Capsules by source naturals
- **How much does it cost?** ¥19049 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/7194707-magtein-magnesium-l-threonate-667mg-supports-focus-mood-healthy-memory)

## Best For

- source naturals enthusiasts

## Why This Product

- Trusted source naturals brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Brain-Barrier Penetration:** Uniquely formulated to cross the blood-brain barrier, ensuring magnesium reaches your neurons where it matters most.
- • **Neuro-Optimized Magnesium:** 667mg of premium Magnesium L-Threonate designed to elevate cognitive function and memory recall.
- • **Stress-Resilience & Mood Lift:** Scientifically shown to increase stress resilience, boost mood, and improve sleep quality for sharper days and restful nights.
- • **Trusted Legacy & Quality Assurance:** Manufactured in the USA under strict cGMP standards by Source Naturals, a brand with over 40 years of health innovation.
- • **Clinically Proven Cognitive Support:** Enhances episodic memory, working memory, executive function, and attention — the four pillars of mental performance.

## Overview

Source Naturals Magtein Magnesium L-Threonate delivers 667mg of a patented magnesium compound clinically proven to support focus, mood, healthy memory, and overall cognitive function. Manufactured in the USA under FDA cGMP standards, this supplement uniquely crosses the blood-brain barrier to enhance four key cognitive domains. Trusted since 1982, it’s a top-rated choice for professionals seeking mental clarity and resilience.

## Description

Buy Source Naturals Magtein Magnesium L-Threonate, 667mg, Supports Focus, Mood, Healthy Memory, Cognitive Function - 180 Capsules on desertcart.com ✓ FREE SHIPPING on qualified orders

Review: Some nice surprises, great product - So, you try a supplement which is supposed to help your brain and your memory, but you know in the back of your mind that it won’t. But guess what? This one did! I started remembering things I forgot that I knew. Even little details! I was taking it for about three months when it dawned on me that I was having this memory recall. Definitely worth buying. As an added bonus, it helps keep your digestion regular because it’s magnesium.
Review: Passes the blood/brain barrier - This is an excellent product. It passes the blood/brain barrier. Helps generally and in preventing headaches.

## Features

- MAGTEIN BENEFITS. Known to increase resilience to stress, lift mood, raise your energy levels, improve concentration and focus and reformation of sleep quality.
- BENEFITS COGNITIVE ABILITY. There are 4 aspects of cognitive ability that they were positively effected by taking Magtein, episodic memory, working memory, executive function, and attention.
- EXCELLENT SOURCE OF MAGNESIUM L THREONATE. There are countless ways to get other forms of magnesium naturally in your diet, but food sources of magnesium L threonate do not exist because it’s a synthesized form.
- OVER 40 YEARS OF TRUST. Source Naturals was created in 1982 by CEO Ira Goldberg to support each individual's potential to enjoy optimal health.
- MANUFACTURED IN THE USA. Manufactured in Scotts Valley, CA, under the Good Manufacturing Practices (cGMPs) established by the US Food and Drug Administration. (FDA)

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN  | B00AXTO30G |
| Best Sellers Rank | #23,706 in Health & Household ( See Top 100 in Health & Household ) #427 in Magnesium Mineral Supplements #1,873 in Sales & Deals |
| Customer Reviews | 4.6 4.6 out of 5 stars (1,888) |
| Date First Available  | January 7, 2013 |
| Is Discontinued By Manufacturer  | No |
| Item model number  | SN2486 |
| Manufacturer  | Source Naturals |
| Product Dimensions  | 1.3 x 1.3 x 1.6 inches; 1.6 ounces |

## Product Details

- **Brand:** Source Naturals
- **Flavor:** Unflavored
- **Item Form:** Capsules
- **Primary Supplement Type:** Magnesium
- **Unit Count:** 180.0 Count

## Images

![Magtein Magnesium L-Threonate, 667mg, Supports Focus, Mood, Healthy Memory, Cognitive Function - 180 Capsules - Image 1](https://m.media-amazon.com/images/I/61K88UFg5JL.jpg)

## Available Options

This product comes in different **Size, Flavor** options.

## Questions & Answers

**Q: 3 capsules contain 2 gm magnesium l-threonate and 144 mg of magnesium.  How much L-threonate is this?   Product label says nothing.**
A: Hi...  The l-threonate is just a metabolite (salt) of vitamin C that is bound to the magnesium as a chelation agent to supposedly make the magnesium more bioavailable, particularly in the brain.  It's not a substance that acts independently, or is counted independently, of the magnesium.  It takes 2 gm of magnesium l-threonate to get 144 mg of actual elemental magnesium, such as you might find in more commonplace magnesium supplements... it's just that binding the magnesium with a chelation agent (in this case l-threonate) may make each mg of magnesium more bioavailable (esp in the brain), than larger amounts of regular magnesium.  Wonder if you're thinking of, and maybe looking for, l-theanine?  That's a totally different substance (supposed to provide a relaxed alertness) from green tea.  If that's what you want, it is available as its own thing.

**Q: why does my bottle show Maltodextrin in the "other ingredients" but on the website label it does not show it?  I bought this based on the ingredients.**
A: This problem needs to be addressed and not pawned off. The June/July2016 reviews have a higher level of complaints. Update the photos if the manufacturer has changed ingredients!

**Q: why 2000 mg in some and 645 mg in others**
A: 2000 mg of magnesium threonate will yield 144 mg of elemental magnesium.  This seems to be the recommended daily dosage.  Three capsules, each containing 645 mg of magnesium threonate will be needed to give a daily dosage of 1935 mg (which is the same as 2000 mg within rounding error).  But some brands use two larger capsules to provide the recommended daily dosage and these may be harder to swallow for some people.

**Q: Is it best to take with food or on empty stomach?**
A: Best on an empty stomach.  I take 2 am and 1 pm.  Directions are 3 per day with 1 taken a few hours before bedtime and 2 taken during the day.  I read that magnesium absorbs best on an empty stomach and some supplement instructions recommend taking that way also.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Some nice surprises, great product
*by K***E on October 21, 2024*

So, you try a supplement which is supposed to help your brain and your memory, but you know in the back of your mind that it won’t. But guess what? This one did! I started remembering things I forgot that I knew. Even little details! I was taking it for about three months when it dawned on me that I was having this memory recall. Definitely worth buying. As an added bonus, it helps keep your digestion regular because it’s magnesium.

### ⭐⭐⭐⭐⭐ Passes the blood/brain barrier
*by J***G on August 11, 2025*

This is an excellent product. It passes the blood/brain barrier. Helps generally and in preventing headaches.

### ⭐⭐⭐⭐⭐ Comprehensive mind with these supplements.
*by H***S on January 15, 2026*

These supplements help me understand things better. And go to the bathroom better. Thanks.

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-02-15*