An attestation letter from the manufacturer will suffice (provided that this is not inconsistent with the ingredient list in the TMA). Note that the claim should simply convey that the product does not have the ingredient. The presentation should not accord or imply any clinical significance to this fact (e.g. safety implications) nor should the presentation disparage the ingredient or products which have the ingredient. Also note that the claim should be disclaimed with “clinical significance has not been established”.