Sometimes people's hair react to one kind of protein but not to another (and that is more likely to happen on healthy hair as the protein will just 'sit' on the cuticle) so maybe you can still find one that will work for you. Also, amino acids penetrate the hair better so look for a CO that lists protein like that. But since your problem was a few split ends (or middles) maybe a moisturizing CO like Jessicurl's Weekly Treatment to soften your hair may be enough for you.
2A/3A, medium length, layered, colored dark/medium ash blonde - "CGer" since April '02.
"Converting the 'curlskeptics' one curly head at a time..." HWHC