Here's a fascinating article from the Thyroid Pharmacist. It's called Which Protein is Safe for Hashimoto's.
It shares some excellent insights. Rootcolog Al Paleo looks particularly interesting:
Most protein powders on the market contain soy and dairy, which are two very reactive proteins for people with Hashimoto’s. While egg white proteins are also an option and can be less reactive, unfortunately, those with Hashimoto’s who start using them often find themselves with new onset egg reactions, because egg whites are difficult to digest for people with intestinal permeability.
Take a look at the rest of ...