Hi Patricia,   Here are the differences:   Wheat free - No part of the whole wheat grain is in the product, meaning no bran, germ, or endosperm layers.   Cornstarch free - Whole grain corn contains the three layers - bran, germ, endosperm, while cornstarch is refined and the bran and germ are removed leaving just the endosperm.  Cornstarch free means there is no refined corn present (endosperm) in the product.   Gluten free - Gluten is a protein found in wheat, rye, and barley.  If a product is gluten free it contains no form of wheat, rye, or barley.    All the best,   Lisa Nelson, RD, LN The Heart of Health - Heart Health and Weight Loss Tips