A reader asked about L-Cysteine not being listed on labels. VRG Researcher Jeanne Yacoubou replied: L-cysteine can in certain situations be in products without it being listed on a label. This is the case, for example, in some prepackaged kits, such as pizza. The premade dough may have L-cysteine but it doesn’t have to be labeled since it’s not part of the finished product. This, and other similar products, could be other likely places for unlabeled L-cysteine.

L-cysteine may also serve as a reaction flavor which is used to make other flavors. Only the latter are in the final product and so only they need to be labeled.

For more information on food ingredients and to purchase our Guide to Food Ingredients, please visit our website at http://www.vrg.org/ingredients/index.php

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The contents of our website and our other publications, including Vegetarian Journal, are not intended to provide personal medical advice. Medical advice should be obtained from a qualified health professional. We often depend on product and ingredient information from company statements. It is impossible to be 100% sure about a statement, info can change, people have different views, and mistakes can be made. Please use your best judgment about whether a product is suitable for you. To be sure, do further research or confirmation on your own.