Life Extension · Magnesium · Capsules
Is Life Extension Neuro-Mag Magnesium L-Threonate underdosed?
Verdict
144 mg a dayas the label directs · studies use 300 mg a day or more · supplement upper limit 350 mg
Below research doseTaken as the label directs (1 serving a day, 144 mg each), it gives 144 mg a day. Studies of magnesium supplements use 300 mg a day or more; the RDA is 400–420 mg for men and 310–320 mg for women, counting food, and the US upper limit for magnesium from supplements is 350 mg a day. That is below the 300 mg a day that raised blood magnesium in the trials.
One capsule gives 48 mg, so reaching the low end of what studies use (300 mg) takes 6.3 capsules a day; it ranks 15th of 21 magnesium supplements here by dose.
To reach the research dose. It would take 7 capsules a day (336 mg) to reach the 300 mg studies use, more than the label's directions, which allow 3 capsules a day (1 serving a day).
What the label says
- Magnesium per serving
- 144 mg in 3 capsules
- Servings a day
- 1 serving a day
- Magnesium a day, as directed
- 144 mg
- Reference
- studies use 300 mg a day or more · supplement upper limit 350 mg Evidence: Moderate
Directions: Take three (3) capsules daily, or as recommended by a healthcare practitioner. Magnesium L-Threonate has less of a laxative effect than other forms of magnesium.
More about magnesium: forms, timing and the studies behind the dose.
Same category, compared
All 21 magnesium supplements we checked, ranked by dose (commission never changes the order). Studies use 300 mg a day or more · supplement upper limit 350 mg; servings counted to 300 mg.
| Product | Per serving | Servings to reach it | Form |
|---|---|---|---|
| Country Life Magnesium Glycinate | 350 mg | 1 or less | Tablets · magnesium bisglycinate |
| Solaray High Absorption Magnesium Glycinate 350 mg | 350 mg | 1 or less | Powders · magnesium bisglycinate |
| BioEmblem Triple Magnesium Complex | 300 mg | 1 or less | Capsules · magnesium malate, glycinate, citrate |
| Natural Vitality Calm | 325 mg | 1 or less | Powders · magnesium carbonate |
| BiOptimizers Magnesium Breakthrough | 500 mg | 1 or less | Capsules · magnesium proprietary blend 1711 mg |
| Bluebonnet Magnesium Citrate | 400 mg | 1 or less | Tablets · magnesium citrate |
| Doctor's Best High Absorption Magnesium 200 mg | 200 mg | 1.5 | Tablets · albion magnesium lysinate glycinate chelate 2000 mg |
| Doctor's Best High Absorption Magnesium Powder | 200 mg | 1.5 | Powders · magnesium lysinate glycinate chelate 2000 mg |
| Nature's Bounty Magnesium 500 mg | 500 mg | 1 or less | Tablets · magnesium oxide |
| NOW Foods Magnesium Citrate | 400 mg | 1 or less | Capsules · magnesium citrate 2667 mg |
| KAL High Absorption Magnesium Glycinate | 315 mg | 1 or less | Capsules · magnesium bisglycinate |
| Nature Made Magnesium 250 mg | 250 mg | 1.2 | Tablets · magnesium oxide |
| Puritan's Pride Magnesium Glycinate | 240 mg | 1.3 | Capsules · magnesium glycinate |
| Nutricost Magnesium Oxide 375 mg | 210 mg | 1.4 | Capsules · magnesium oxide |
| Life Extension Neuro-Mag Magnesium L-Threonate (this product) | 144 mg | 2.1 | Capsules · magtein 2000 mg |
| NOW Foods Magtein | 144 mg | 2.1 | Capsules · magtein 2000 mg |
| Sports Research Magnesium L-Threonate | 144 mg | 2.1 | Capsules · magtein 2000 mg |
| Pure Encapsulations Magnesium (Glycinate) | 120 mg | 2.5 | Capsules · magnesium glycinate |
| Thorne Magnesium Glycinate | 120 mg | 2.5 | Capsules · magnesium glycinate |
| Natural Vitality Calm Capsules | 100 mg | 3 | Capsules · magnesium glycinate |
| Double Wood Supplements Magnesium Glycinate 400 mg | 60 mg | 5 | Capsules · magnesium glycinate |
Where the reference doses come from
- Magnesium, 300–350 mg/day: Zhang et al., 2016.
- Label data: National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Label Database, 2026. https://dsld.od.nih.gov/. Label 328600, including its servings a day.
For a supplement taken every day we judge the most the label's directions give in a day, and show the least. Read the full methodology or the corrections log.