Leucine
A safe and naturally occurring essential amino acid.
- Category
- Flavour enhancers
- Vegan
- Yes
- Vegetarian
- Yes
What it is
An essential amino acid sometimes used as a flavor modifier or tableting lubricant.
How it is used in food
An essential branched-chain amino acid used as a flavor modifier and processing aid; nutritionally, leucine is a key trigger of muscle protein synthesis.
Commonly found in- Food supplements
- Sweeteners
Health and safety
Completely safe; it is an essential dietary amino acid.
As an essential amino acid consumed in gram quantities daily from ordinary protein foods, leucine has no relevant toxicity at additive levels. It also appears in pharmaceutical tabletting as a safe excipient.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted under the FSANZ Food Standards Code. |
| European Union EFSA / European Commission |
Permitted | Authorised for food use under EU regulations (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
- E641
Worth knowing
Leucine is the same amino acid bodybuilders seek in whey protein and BCAA supplements — the amounts used as a food additive are trivial compared with normal dietary intake.
Conclusion
A safe and naturally occurring essential amino acid.
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Open the appEntry last reviewed 2026-07-28.
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