@fatsfat My functional medicine doctors have been covered in-network in Blue Cross networks. You can always start a search on an insurance company website for in network doctors, and then go to that doctor's website. My functional medicine specialists have been allergy doctors in addition to an interest in tweaking health with thyroid function, etc. They have not been family practice doctors, and are MDs, but don't treat illnesses and injuries. Practitioners who are not MDs can fall into this category and are often not in insurance networks. Some doctors don't want to be in insurance networks because it is a contract on what they can earn as the in-network discounted rate, and then their treatments have to be approved for coverage which limits them. Sometimes word of mouth is the best way to find them which is how I found my current functional medicine doctor after one retired and closed his practice. His office staff gave me the name of a similar MD in my area.