GNC has reached an agreement with New York Attorney General Eric Schneiderman to develop a number of procedures to ensure that its supplements contain the ingredients advertised. Earlier in 2015, Schnei- derman sent cease-and-desist letters to GNC and four other retailers after testing their herbal supplements and finding that the products did not contain the advertised supplement or were contaminated with potential allergens. Under the agreement, GNC will perform DNA barcoding on “active” plant ingredients in its products to authenticate the herbal ingredients, test for potential allergens, and post signs advising customers of “the processed, chemical nature of extracts.”