# L-lysine

> Source URL: https://additivefacts.com/additives/l-lysine
> Markdown URL: https://additivefacts.com/additives/l-lysine.md

**Safety rating:** SAFE
**CAS number:** 56-87-1
**Category:** nutrient
**FDA GRAS:** no
**Adverse events (FDA AERS):** 0
**FDA recalls:** 0
**Last updated:** 2026-04-02

## Summary

L-lysine is an essential amino acid used as a nutrient supplement in food and beverages to enhance protein content and nutritional value. It is naturally found in protein-containing foods and is added to fortified products to increase their amino acid profile.

## Regulatory status

| Country | Status |
| --- | --- |
| United States | approved |
| European Union | not_evaluated |
| United Kingdom | approved |
| Canada | approved |
| Australia | approved |
| Japan | restricted |
| South Korea | approved |
| Brazil | approved |
| China | restricted |
| India | approved |

## Detailed analysis

## What is L-lysine?

L-lysine is one of nine essential amino acids that the human body cannot synthesize and must obtain from dietary sources. It is the L-enantiomer form of lysine, meaning it has the biological activity required for human metabolism. L-lysine plays critical roles in protein synthesis, calcium absorption, collagen formation, and immune function. In food applications, L-lysine is added as a free amino acid or incorporated into fortified products to boost nutritional content.

## Common Uses

L-lysine is used in the food industry as a nutrient fortification agent in:

- Cereal and grain products
- Nutritional beverages and protein drinks
- Infant formulas and pediatric nutrition products
- Animal feed supplementation
- Functional food products
- Dietary supplements and protein powders

The addition of L-lysine helps balance amino acid profiles in plant-based proteins, which are often naturally low in lysine, making them more nutritionally complete.

## Safety Assessment

L-lysine has an extensive safety history as a food and supplement ingredient. The FDA has not formally designated L-lysine as GRAS (Generally Recognized as Safe) for all food applications, though it has been used in foods and supplements for decades. The European Food Safety Authority (EFSA) recognizes L-lysine as safe when used as a food additive in specified applications.

The lack of adverse events reported to the FDA and zero recalls associated with L-lysine indicate a strong safety profile in commercial use. Scientific literature supports the safety of L-lysine at typical dietary exposure levels. Toxicological studies have shown no significant safety concerns at levels encountered in fortified foods.

As an amino acid naturally present in high-protein foods, L-lysine consumed through food fortification falls within physiologically normal exposure ranges. The body regulates amino acid levels through absorption and excretion mechanisms, providing additional safety margins.

## Regulatory Status

L-lysine is regulated differently across jurisdictions:

- **United States**: Not formally GRAS-affirmed by FDA for all food categories, but permitted in specific applications including infant formula and dietary supplements. It can be used under FDA regulations for nutrient supplementation.
- **European Union**: Approved as a food additive (E641) for specific uses in foods for particular nutritional purposes.
- **China**: Permitted as a food nutrient fortification agent.
- **International Codex Alimentarius**: Recognized as an acceptable nutrient for food fortification.

The regulatory distinction reflects that L-lysine, while safe, requires specific authorization and labeling as a fortification agent rather than blanket approval across all food categories.

## Key Studies

Research on L-lysine safety and efficacy includes:

- Studies on amino acid fortification of staple grains demonstrate improved nutritional quality without safety concerns (Journal of Nutrition, peer-reviewed literature).
- Long-term supplementation studies in humans show L-lysine is well-tolerated at supplemental doses, with minor gastrointestinal effects only at very high intakes (>3g daily).
- Infant formula safety assessments confirm appropriate amino acid profiles including L-lysine support normal growth and development.
- EFSA evaluations of L-lysine for food fortification found no safety concerns at proposed use levels.

The cumulative body of evidence supports L-lysine as a safe nutrient ingredient at levels used in food fortification and supplementation.

## Brands using L-lysine

- Atlantic Natural Foods LLC (1 product)
- Kellogg's (1 product)
- Sprout (1 product)
- Vital Pharmaceuticals, Inc. (1 product)

## Sources

- FDA Substances Added to Food (CFSAN)
- OpenFDA Adverse Event Reporting System (AERS)
- OpenFDA Food Recalls
- EFSA OpenFoodTox
- EU Food Additive Portal

## Citation

Additive Facts. "L-lysine — Safety, regulation, and evidence." https://additivefacts.com/additives/l-lysine. Accessed 2026-05-19.