L. Cysteine
L. Cysteine carries a safety score of 3/5 and appears in 46 indexed US food products.
3/5 from FDA SAFFA + CSPI Chemical Cuisine
How common is vs other flagged additives?
Number of indexed products containing each of the most common flagged additives — L. Cysteine highlighted.
Indexed products containing each flagged additive. Source: Open Food Facts ingredient lists × FDA SAFFA × CSPI Chemical Cuisine.
Safety Assessment
L. Cysteine has a moderate safety profile (3/5). While approved for use, some studies or consumer advocacy groups have raised questions about certain aspects of this ingredient. Consumers who prefer caution may wish to limit intake.
What the Data Says About
L. Cysteine currently appears in 46 products across the OpenFoodFacts catalog we index, which gives a concrete measure of its footprint on US grocery shelves. Our internal safety score of 3/5 synthesizes FDA Substances Added to Food (SAFFA) regulatory status with the Center for Science in the Public Interest (CSPI) Chemical Cuisine classification. These two frameworks capture different questions: regulators ask whether exposure at typical intake is acceptable, while consumer-advocacy groups examine cumulative dietary load and vulnerable-population risk.
L. Cysteine serves one or more technical functions in food manufacturing — stabilization, flavor, preservation, or structural role — which explains its presence across multiple product categories in our database. Inspection and outbreak records frequently trace back to control failures around functional additives, whether through batch contamination, undisclosed substitutions, or labeling mismatches that trigger recall classifications by the FDA.
No specific concern flags are attached to L. Cysteine in our current data snapshot beyond the regulatory and CSPI classifications above. That does not rule out individual sensitivity reactions, and anyone managing allergies, elimination diets, or chronic conditions should verify with a qualified healthcare professional before relying on population-level ratings.
Safety Profile at a Glance
| Source | Classification | Year |
|---|---|---|
| FDA SAFFA | Not listed | 2024 |
| CSPI Chemical Cuisine | Not rated | 2024 |
| PlainFoodSafe Score | 3/5 | 2026 |
| Product footprint | 46 products | OpenFoodFacts |
FDA SAFFA database, CSPI Chemical Cuisine ratings, OpenFoodFacts product index. See methodology.
Products Containing
Showing 46 of 46 products
Frequently Asked Questions
Is L. Cysteine safe to eat? ▼
L. Cysteine has a safety score of 3/5. Always check with a healthcare provider if you have specific dietary concerns.
What products contain L. Cysteine? ▼
L. Cysteine is found in 46 products in our database, spanning various food categories and brands.
What does L. Cysteine do in food? ▼
L. Cysteine serves various technical functions in food manufacturing and processing.
Where does this ingredient safety data come from? ▼
Safety data comes from the FDA's SAFFA (Substances Added to Food) database, CSPI (Center for Science in the Public Interest) ratings, and the OpenFoodFacts product database. Product counts reflect items cataloged in OpenFoodFacts.