The Curly Girl Method claims that conventional shampoos are full of harsh ingredients that strips the hair of all the moisture and sebum and hair is left dry, brittle, frizzy and unmanageable. To avoid this, it is recommended to avoid all shampoos and instead a conditioner should be introduced to cleanse the hair. This is what we know as co-washing or using a conditioner to wash the hair (no-poo hair care).
These harsh ingredients are so effective in what they do that they also strip the natural oil in our hair (sebum) leaving our hair unprotected from external damage and from quick moisture release. For straight hair, this is not a big deal since sebum can travel along the hair shaft quite easily. However, for us curly girls this is bad news because sebum can only protect the hair closest to the roots. The coils and kinks in natural or transitioning hair prevent sebum from travelling from roots to ends.
Co-washing not only saves our curls from this stripping ritual but it can also be an effective cleanser. They contain ingredients that have cleansing properties but they also provide emollients to soften the hair like oils and butters, humectants to keep moisture in like glycerine, panthenol or honey and some have proteins to help strengthen the hair like soy, wheat or silk protein.