| Vegan? Maybe | Vegetarian? Maybe |
Classifications are made based on the available commercial supply of the ingredient, and are made based on the criteria on our classifications page.
Commercially available l-cysteine may be vegan depending on the source and may be vegetarian depending on the source.
L-cysteine is an amino acid found primarily in animals. It may be produced from duck feathers, synthetically, or from bacteria. Currently, approximately 80% of commerical l-cysteine comes from duck feathers.