L-Isoleucine

L-isoleucine is an essential branched chain amino acid that aids in muscle metabolism and energy regulation. It can be used as a nutrient.

Found In
  • Beverages
  • Dietary supplements
  • Energy drinks
  • Protein powder beverages
  • Sports drinks
  • Naturally occurring in eggs, fish, meat, milk and poultry
Also Known As
  • Isoleucine
The Beverage Bottom Line

L-isoleucine is authorized for use in the U.S., Europe and Canada.

This ingredient may have authorizations in countries not included on this site.


International Assessments and Authorizations


U.S. Food And Drug Administration

Generally recognized as safe for intended uses. ()

In 2005 and 2006, dietary reference intakes for L-isoleucine were reviewed by the National Academies of Sciences, Engineering and Medicine.

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European Food Safety Authority

Safe for intended uses. Permitted for addition in dietetic foods.

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Joint FAO/WHO Expert Committee on Food Additives

Safe for intended uses.

In 2007, WHO published a Technical Report on Protein and Amino Acid Requirements in Human Nutrition.

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Safe for intended uses. Permitted as a supplemental ingredient.

In 2005 and 2006, dietary reference intakes for L-isoleucine were reviewed by the National Academies of Sciences, Engineering and Medicine.

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This page was last updated on 6/30/2025