Back to catalogSafety
E572Anti-caking agentLow concern
Magnesium Stearate
In plain words
The short version
The dominant tablet lubricant in pharmaceuticals and supplements — frequently the subject of unfounded online controversy.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
ADI not specified — considered safe. Expected to dissociate in the gut into fatty acids (mainly stearic and palmitic acid) and magnesium. The fatty acids are absorbed and metabolised like other dietary fatty acids, and the small amount of magnesium enters normal physiological processes. The recurring social-media controversy is not supported by systematic-review evidence.
The detail
Produced by reacting stearic acid with magnesium hydroxide or magnesium oxide. Manufactured at scale specifically for the pharmaceutical and supplement industries — the dominant tablet and capsule lubricant by mass.
The standard tablet and capsule lubricant — prevents powders from sticking to compression dies and improves capsule fill flow. Typically 0.25–2.0% of tablet weight. In food, occasional use as an anti-caking agent in powdered seasonings and as a release agent in chewing gum.
Light, fluffy white powder with a characteristic waxy feel. Insoluble in water; insoluble in cold organic solvents.
Permitted globally without restrictive limits.
Sources
- EFSA: Re-evaluation of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) as food additives (EFSA Journal 2018;16(3):5180), PMC full text — European Food Safety Authority (ANS Panel), 2018. What happens in digestion (safety tab); EU safety re-evaluation
- WHO JECFA database: Magnesium stearate (INS 470(iii)), ADI not specified (2015; specifications revised 2020) — WHO / FAO Joint Expert Committee on Food Additives, 2015. ADI not specified
- US eCFR: 21 CFR 184.1440 Magnesium stearate (GRAS) — US Office of the Federal Register / FDA, 2026. US status: no limitation other than GMP
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.