I have certain detergent allergies, and for years I could only use shampoos containing salicylic acid, or die from itchy scalp. I wanted to try something gentler, but effective, and started my search.
I read an article about Cetaphil Lotion Cleanser being used as a shampoo, and bought 2 bottles at COSTCO, with a bonus of the cleansing bar.
The lotion cleanser is wonderful for removing make-up, and for very gentle cleansing. I didn't feel it really cleaned my hair well, and I might have returned to the salicylic acid shampoos, but I decided to try the cleansing bar on my scalp as it foamed well and rinsed well on my skin.
Eureka! The cleansing bar, which is downright CHEAP for what it does, makes a fabulous hair shampoo. And, I know this seems nuts, but I deliberately placed suds in my eyes and there was no stinging (generic bars DO sting, but not Cetaphil).
I'm happy-happy-happy, and I no longer have to scan Ebay for sales on psoriasis preventive shampoo!