Magnesium stearate
A very safe, ubiquitous supplement additive.
- Category
- Anti-caking agents
- Vegan
- maybe
- Vegetarian
- maybe
What it is
A magnesium salt of stearic acid, widely used as a flow agent and lubricant in pill manufacturing.
How it is used in food
The workhorse flow agent and lubricant of the supplement and pharmaceutical industries: a thin coating of it stops powders sticking to tableting machinery, ensuring uniform doses in tablets and capsules.
Commonly found in- Dietary supplements
- Pills
- Confectionery
Health and safety
Completely safe and heavily used in the pharmaceutical and supplement industries. Included in the EU under E470b.
Safety reviews, including EFSA's assessment of the magnesium salts of fatty acids (covered under E470b in the EU), found no toxicological concern; it dissociates into magnesium and stearic acid, both normal dietary components. Internet claims that it suppresses immune function trace back to a misread study on stearic acid and mouse T-cells, and are not supported by human evidence.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted under the FSANZ Food Standards Code. |
| European Union EFSA / European Commission |
Not approved | Not on the EU authorised list of food additives (Annex II). |
| United States FDA (Food and Drug Administration) |
Permitted | Authorised for food use by the FDA (often GRAS for standard additives). |
Identification on labels
- E-number
- E572
Worth knowing
It is found in the vast majority of tablets on the market, yet the amount per tablet is tiny — typically under 1% of the formulation — meaning a magnesium stearate 'dose' from pills is trivial next to the stearic acid in a piece of chocolate.
Conclusion
A very safe, ubiquitous supplement additive.
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Open the appEntry last reviewed 2026-07-28.
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