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- Magnesium Chloride or Epsom Salt – What’s the Difference?
Magnesium Chloride or Epsom Salt – What’s the Difference?
Magnesium chloride hexahydrate and magnesium sulfate heptahydrate are not the same ingredient
Magnesium ingredients can easily cause confusion. Magnesium chloride hexahydrate and magnesium sulfate heptahydrate both contain magnesium, but their properties and practical uses are different.
Magnesium chloride hexahydrate
Magnesium chloride hexahydrate has the chemical formula MgCl₂·6H₂O.
It is highly soluble in water and is particularly useful for preparing concentrated aqueous solutions.
The best-known example is so-called magnesium oil. Despite the name, it contains no oil. The term comes from the slightly slippery, oil-like feel that a concentrated magnesium chloride solution leaves on the skin.
It is commonly used for:
- mineral body sprays,
- roll-on formulations,
- water-based cosmetic solutions.
Higher concentrations may sting or tingle, especially on dry, freshly shaved or irritated skin.
Magnesium sulfate heptahydrate – Epsom salt
Magnesium sulfate heptahydrate has the formula MgSO₄·7H₂O and is widely known as Epsom salt.
It is a white or colourless crystalline material that dissolves readily in water.
It is especially useful in:
- bath salts,
- foot soaks,
- bath bombs,
- mineral bath blends.
Quick comparison
| Feature | Magnesium chloride hexahydrate | Magnesium sulfate heptahydrate |
|---|---|---|
| Formula | MgCl₂·6H₂O | MgSO₄·7H₂O |
| Common name | magnesium chloride / magnesium oil base | Epsom salt |
| Water solubility | very good | very good |
| Typical DIY use | sprays and solutions | baths and bath salts |
| Concentrated spray | suitable | less practical |
| Bath salts | possible | especially suitable |
Basic mineral body spray – 100 g
- 33 g magnesium chloride hexahydrate
- 66.4 g distilled water
- 0.6 g Cosgard
Total: 100 g
For a gentler version:
- 20 g magnesium chloride hexahydrate
- 79.4 g distilled water
- 0.6 g Cosgard
Method
Warm the distilled water to approximately 40–50 °C.
Add magnesium chloride and stir until fully dissolved.
Allow to cool below 40 °C, add Cosgard and transfer into a clean spray bottle.
How is Epsom salt used?
For a full bath, add approximately 150–300 g Epsom salt to warm water.
For a foot soak, approximately 50–100 g in a basin of warm water is sufficient.
Does magnesium pass through the skin?
Magnesium sprays and baths are popular for external use, but they should not be treated as substitutes for dietary magnesium.
The movement of magnesium ions through healthy, intact skin is limited, so topical products should not be relied upon to correct magnesium intake or deficiency.
For nutritional magnesium intake, use food or products specifically labelled and intended for oral use. Magnesium chloride is also used in dietary supplements, while magnesium sulfate has recognised oral medicinal uses in specific formulations and doses.
Which one should you choose?
Magnesium chloride hexahydrate → sprays and aqueous solutions
Magnesium sulfate heptahydrate → baths and bath salts
