Systems and methods are provided for authenticating a product over a payment network. A product identifier associated with a product to be authenticated may be included or appended to a conventional authorization request message or clearing message during processing of a payment transaction. The product identifier can be verified at a verification entity to determine whether the product is real or counterfeit. Authorization or settlement of the payment transaction can be approved/processed if the product is determined to be real. Authorization or settlement of the payment transaction can be declined/withheld if the product is determined to be counterfeit.