@blbird33
I don't know about shampoo, however I used oral biotin tablet/capsule. My dermatologist suggested the amount and my transplant team okayed it.
As for shampoo, my hairdresser who took care of cancer patients, recommended a gentle shampoo that she used and sold to them. I don't remember the name. Do you have such specialty beautician/hairdresser near you as a resource?