Magnesium Chloride
Also known as: MgCl2, magnesium chloride hexahydrate, Mg chloride, magnesium chloride flakes
A highly soluble magnesium salt sold as the hexahydrate, which is about 12% elemental magnesium. It is used in liquid magnesium drops, electrolyte powders, and some tablets, and is the form in several of the clinical trials from Mexican research groups. Solubility gives it good bioavailability relative to oxide, and its salty, bitter taste is the main formulation hurdle. It is also the raw material for topical magnesium products.
Research summary
Supplies fully ionized magnesium in solution for enzymatic, neuromuscular, and electrolyte functions; chloride contributes to fluid balance.
Dosage
Daily amounts, elemental (12% of the compound is the element).
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 100 mg | 100–300 mg | 350 mg | 350 mg |
NIH ODS — UL of 350 mg applies to supplemental magnesium only, not magnesium from food
Doses are elemental magnesium. Magnesium chloride hexahydrate (MgCl2·6H2O, MW 203.3) is ≈ 12% Mg; anhydrous MgCl2 is ≈ 25.5% but is hygroscopic and rarely used. Take with water or food; loose stools can occur at higher doses. Capped at the 350 mg supplemental UL.
Source material: brine or seawater evaporation; synthetic grades also available
As supplied: Hexahydrate ≈ 12% Mg; anhydrous ≈ 25% Mg
Forms of Magnesium
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Magnesium Chloride | 100–300 mg | 12% | Capsule, Powder, Tablet, Liquid | low |
| Magnesium Glycinate | 200–350 mg | 14% | Capsule, Powder, Tablet | low |
| Magnesium Citrate | 150–350 mg | 16% | Capsule, Powder, Tablet, Gummy, Liquid | low |
| Magnesium Oxide | 200–350 mg | 60% | Capsule, Powder, Tablet, Gummy | low |
| Magnesium L-Threonate | 100–144 mg | 7% | Capsule, Powder, Tablet | high |
| Magnesium Malate | 100–350 mg | 16% | Capsule, Powder, Tablet | low |
| Magnesium Taurate | 100–300 mg | 9% | Capsule, Powder, Tablet | mid |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Strongly bitter and salty; liquids and powders need flavor masking. Hygroscopic and deliquescent, so bulk powder must be kept dry and capsules may need desiccant. 200 mg elemental ≈ 1,670 mg of hexahydrate.
Formulation notes
Adds chloride to electrolyte formulas. Separate from bisphosphonates and some antibiotics.
- Has an upper limit
Sources
Related ingredients
Magnesium Glycinate
MineralA chelated form of magnesium bound to the amino acid glycine.
Typical: 200–350 mg
Magnesium Citrate
MineralMagnesium bound to citric acid, one of the best-selling magnesium forms because it is inexpensive, dissolves readily, and has shown good bioavailability in comparison studies.
Typical: 150–350 mg
Taurine
Amino acidA sulfur-containing amino acid abundant in muscle, heart, and brain, and a familiar ingredient in energy drinks and pre-workouts.
Typical: 1–3 g
Potassium Chloride
MineralThe most concentrated common potassium source at about 52% elemental potassium, and the salt used in most blood-pressure trials of potassium supplementation.
Typical: 99–500 mg
Magnesium Taurate
MineralA complex of magnesium with the amino acid taurine, chosen for cardiovascular and calming formulas because both components are studied in relation to blood pressure and nervous-system excitability.
Typical: 100–300 mg