Hello,

I am creating a hair care product guide based on criteria of my choice. What can you tell me about the best ingredients and worst ingredients to look for in a given hair product? (Anything from shampoo and conditioner to straightening and thickening products). What ingredients actually do what they're supposed to do, and which don't. Are there any that are potentially harmful? I'd appreciate any feedback you can give me.

Thanks,
Liz