E641 / Flavour enhancers
L-Leucine
Safety in brief
Safe
Recorded EatMatrix rating, not a new clinical review. The amount, your sensitivities and country rules still matter.
- Watch for
- No allergen or sensitivity is recorded for this ingredient here. Check the whole product label; this is not an allergen-free guarantee.
- Our advice
- Read the whole food label and consider how often you eat the product. A name or E number does not tell you the amount, and an ingredient rating cannot assess the entire food.
What it is
L-Leucine is an essential branched-chain amino acid, meaning the body cannot make it and it must come from food. As a food additive it is mainly used as a flavour enhancer to round out savoury notes, and it is also popular in sports and nutrition supplements for its role in muscle protein synthesis.
Also appears on labels as: L-Leucine, Leucine, L Leucine, 2-Amino-4-methylpentanoic acid, Leu, Essential amino acid leucine, L-Leucine powder, L-Leucine supplement, Leucinum, Leucine (L form), E641, E 641.
What is E641, and why is L-leucine used in sweetener tablets?
E641 identifies L-leucine. EU Regulation 2015/649 assigned this E number when introducing its use as a carrier, or tableting aid, in table-top sweetener tablets. In plain language, it helps stop the tablets sticking to the tools that press them into shape.
That is a food-manufacturing purpose. A reference to L-leucine in a nutrition or sports supplement has a different context: the E641 code on a label does not establish a supplement dose or a health benefit. Match the exact ingredient name, food type and market before interpreting the label.
The 2015 regulation documents this specific sweetener-tablet use; it is not a current review of every EU food category. The FSA Great Britain register lists E641 as authorised in England, Scotland and Wales, subject to the linked conditions of use and specifications. That register entry is not unrestricted permission for every food or a conclusion for other countries.
- Original EU Regulation 2015/649: E641 identity and sweetener-tablet purpose, recitals 4–8 and Annex I
- FSA Great Britain register: E641 L-leucine, territories and linked conditions; updated April 1, 2025
See how EatMatrix reads an ingredient list before trying the app. Compare a scan with the physical label.
Identity and food-use sources checked . The E number alone does not tell you the amount in a product. Wider scientific and market checks are described below.
Dietary information
- Vegan
- Yes
- Halal
- Yes
- Gluten-free
- Yes
- Allergens
- None recorded
Recorded ingredient information. Check the product label or certification: sources, other ingredients and cross-contact can vary.
Research & body effects
Health notes from our ingredient record
- Generally recognized as safe at the levels used as a flavour enhancer or in typical supplement doses.
- Very high supplemental doses of leucine or other single amino acids, taken chronically, may cause amino acid imbalances or strain metabolism in susceptible individuals.
Country rules
Country checks for E641
Permission depends on the market, type of food, amount and conditions. A scientific opinion or an E-number alone does not establish a legal use. These checks are separate from the stored EatMatrix rating.
Compare all eight markets and their sources
| Market | What is checked |
|---|---|
| European Union | Regulation (EC) 1333/2008, Annex II Part B, version , contains the exact code E641: L-leucine. Listing alone does not allow every food use. Part E food categories, limits, specifications and applicable later acts still need a product-specific check. Source read: . |
| Great Britain | The FSA register record for E641 (L-leucine) lists “Authorised” in England, Scotland and Wales. Register updated: 01 April 2025; record checked: . Food-specific conditions and specifications still need a separate legal check. |
| United States | Complete current-use review pending. Any scoped provision in the label guide above applies only to the stated use. FDA explains the applicable food-additive and GRAS framework. |
| Northern Ireland | Review pending. Check the applicable EU rules and territory arrangements; the GB register alone does not establish this status. FSA guidance is a starting source, not a verified permission for this entry. |
| Canada | Named food-use records located. Health Canada lists the preparations below for specified foods and purposes. This is conditional permission for those uses, not approval of every product or a personal safety verdict. Only the named records and conditions below were located. Exact composition and specifications still need matching. Source tables captured . List publication dates are shown separately. Good Manufacturing Practice (GMP) is a condition of use, not an unlimited amount or a recommended intake. Food and Drug Regulations B.16.003 requires the listed source, purpose, amount and other conditions to match. The official consolidation read was current to 21 September 2026; product specifications and applicable later changes still need checking. Read 1 listed food-use conditionsL-LeucineHealth Canada: List of Permitted Food Additives with Other Purposes of Use. List published ; item L.5.
EatMatrix reading: match the exact preparation and food first. A manufacturing limit is not an acceptable daily intake (ADI). A label without the amount cannot establish exposure, and an unlisted name here does not establish a ban. |
| Australia | Review pending. Food Standards Code permissions and conditions need an additive-specific check. FSANZ food-additive rules is a starting source, not a verified permission for this entry. |
| New Zealand | Review pending. Food Standards Code permissions and conditions need an additive-specific check. FSANZ food-additive rules is a starting source, not a verified permission for this entry. |
| Japan | Review pending. The relevant list, identity and use standards need an additive-specific check. CAA food-additive lists is a starting source, not a verified permission for this entry. |
Sources & review status
Check what each source covers: an authority’s conclusion, a research finding and a country’s legal permission answer different questions.
What this guide covers
- Original ingredient record
- No research links in the original record. Sources added separately to this guide are not included in this count.
This guide brings together our ingredient record and the dated sources shown here. Missing information describes a gap in this guide; it does not mean an ingredient is untested, safe or harmful. This is not a complete review of every study, preparation or current country rule. The amount in a product and how it is used still matter.
How to read the ratings, research and country checksAgency labels recorded by EatMatrix
These are imported database classifications, not verified current statements from each authority. Use the dated official sources below for their actual scope and conclusions.
| Authority | Database label |
|---|---|
| FDA | Safe |
| WHO | No rating recorded |
| EFSA | Safe |
| FSANZ | Safe |
| Japan | Safe |
| UK FSA | Safe |
| Health Canada | Safe |
Database updated: . What does an E number mean on a food label?
Common questions
Frequently asked questions
What is EatMatrix's recorded rating for E641?
The recorded EatMatrix rating for E641 (L-Leucine) is “Safe”. It is calculated from labels stored in our ingredient database. These labels are not verified current regulator decisions or country permissions. A database update date is not a scientific review date.
Is E641 vegan, halal or gluten-free?
According to our ingredient data for L-Leucine — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E641 and why is it used?
L-Leucine is an essential branched-chain amino acid, meaning the body cannot make it and it must come from food. As a food additive it is mainly used as a flavour enhancer to round out savoury notes, and it is also popular in sports and nutrition supplements for its role in muscle protein synthesis.
Does E641 contain allergens?
No known allergens are recorded for L-Leucine.
Is E641 the same as L-leucine?
E641 identifies L-leucine. EU Regulation 2015/649 assigned that code for its use as a carrier in table-top sweetener tablets. The FSA Great Britain register also names E641 as L-leucine. The ingredient identity alone does not establish a product’s quantity, a supplement dose or a health benefit.
Why is E641 used in sweetener tablets?
The original EU Regulation 2015/649 describes L-leucine as a tableting aid: it is mixed with sweeteners before pressing and helps prevent tablets sticking to the pressing tools. This is a manufacturing function. Food-use permissions depend on the market, food category, conditions and specifications; the code is not unrestricted permission for every product.
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This page shows information and classifications recorded in our ingredient database. Current scientific and market-specific verification remains pending as described above. It is general information, not medical advice.