Magnesium supplements
Magnesium is judged on the elemental magnesium a day the label's directions give, not the weight of the compound it comes in. Trials gave 300 mg a day or more (a median of 368 mg), and 300 mg was enough to raise blood magnesium. The US upper limit for magnesium from supplements is 350 mg a day, and anything over it is flagged. The RDA, 400–420 mg for men and 310–320 mg for women, counts food too. Commission never changes the order.
Powders (3)
| Product | Per serving | Servings a day | Per day, as directed | Verdict | Proof |
|---|---|---|---|---|---|
| Solaray High Absorption Magnesium Glycinate 350 mg · label 25 Sep 2025 | 350 mg in 1 scoop (3.57 g) | 1 serving | 350 mg | Effective dose | Label claim only |
| Natural Vitality Calm · label 22 Feb 2024 | 325 mg | 0.25–1 serving | 81–325 mg | Effective dose | Label claim only |
| Doctor's Best High Absorption Magnesium Powder · label 24 Jan 2024 | 200 mg in 1 scoop (2 g) | 2 servings | 400 mg | Over the upper limit | Label claim only |
Capsules (13)
| Product | Per serving | Servings a day | Per day, as directed | Verdict | Proof |
|---|---|---|---|---|---|
| BioEmblem Triple Magnesium Complex · label 11 Oct 2026 | 300 mg in 2 capsules | 1 serving | 300 mg | Effective dose | Lab tested (Labdoor 2025), found 116% of the label |
| BiOptimizers Magnesium Breakthrough · label 25 Sep 2025 | 500 mg in 2 capsules | 1 serving | 500 mg | Over the upper limit | Label claim only |
| NOW Foods Magnesium Citrate · label 24 Oct 2024 | 400 mg in 3 capsules | 1 serving | 400 mg | Over the upper limit | Label claim only |
| KAL High Absorption Magnesium Glycinate · label 23 Jan 2025 | 315 mg in 3 capsules | 1–1.33 servings | 315–420 mg | Over the upper limit | Label claim only |
| Puritan's Pride Magnesium Glycinate · label 25 Sep 2024 | 240 mg in 2 capsules | 1 serving | 240 mg | Below research dose | Label claim only |
| Nutricost Magnesium Oxide 375 mg · label 16 Jun 2022 | 210 mg in 1 capsule | 1 serving | 210 mg | Below research dose | Label claim only |
| Life Extension Neuro-Mag Magnesium L-Threonate · label 21 May 2025 | 144 mg in 3 capsules | 1 serving | 144 mg | Below research dose | Label claim only |
| NOW Foods Magtein · label 25 Sep 2025 | 144 mg in 3 capsules | 1 serving | 144 mg | Below research dose | Label claim only |
| Sports Research Magnesium L-Threonate · label 24 Apr 2025 | 144 mg in 3 capsules | 1 serving | 144 mg | Below research dose | Label claim only |
| Pure Encapsulations Magnesium (Glycinate) · label 25 Sep 2023 | 120 mg in 1 capsule | 1 serving | 120 mg | Below research dose | Label claim only |
| Thorne Magnesium Glycinate · label 11 Oct 2026 | 120 mg in 1 capsule | 1–4 servings | 120–480 mg | Over the upper limit | Label claim only |
| Natural Vitality Calm Capsules · label 22 Nov 2024 | 100 mg in 2 capsules | 1 serving | 100 mg | Below research dose | Label claim only |
| Double Wood Supplements Magnesium Glycinate 400 mg · label 25 Jul 2024 | 60 mg in 1 capsule | 1–4 servings | 60–240 mg | Below research dose | Label claim only |
Tablets (5)
| Product | Per serving | Servings a day | Per day, as directed | Verdict | Proof |
|---|---|---|---|---|---|
| Country Life Magnesium Glycinate · label 22 Aug 2025 | 350 mg in 3 tablets | 1 serving | 350 mg | Effective dose | Label claim only |
| Bluebonnet Magnesium Citrate · label 21 May 2025 | 400 mg in 2 tablets | 1 serving | 400 mg | Over the upper limit | Label claim only |
| Doctor's Best High Absorption Magnesium 200 mg · label 21 Dec 2024 | 200 mg in 2 tablets | 2 servings | 400 mg | Over the upper limit | Label claim only |
| Nature's Bounty Magnesium 500 mg · label 22 Apr 2021 | 500 mg in 1 tablet | 1 serving | 500 mg | Over the upper limit | Label claim only |
| Nature Made Magnesium 250 mg · label 23 Aug 2022 | 250 mg in 1 tablet | 1 serving | 250 mg | Below research dose | Label claim only |
21 products. Where the directions give a range, the verdict judges the most they give in a day. Read the magnesium guide for the studies behind the dose. "Proof" is a published independent lab test, a certifier listing we read on the certifier's own site (usually for listed lots only), or "Label claim only" when we found neither.