Yes, it has been approved as a safe ingredient by the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), as well as the Joint FAO/WHO Expert Committee on Food Additives (JECFA).

FDA
Glyceryl monostearate is a generally recognized as safe (GRAS) ingredient when used in food with no limitation other than current good manufacturing practice (5). And also, it is GRAS when used in feed. (6)

EFSA

Glyceryl monostearate (E471) belongs to Mono- and Diglycerides of fatty acids and listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “Additives other than colours and sweeteners” (7).

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