Co-washing means to wash your hair with conditioner instead of shampoo. It is a way for you to condition your hair without drying it out – especially if you generally use shampoo containing sulfates. Co-washing is not for everyone. Also, remember there is a such thing as too much moisture. Too much co-washing can also cause split ends.
Some people shy away from co-washing because they think conditioner does not get the hair clean, but there is actually a little detergent in conditioner. Conditioner also helps get rid of some of the product build-up. You can actually co-wash more frequently than you would shampoo.
A lot of naturals co-wash on a daily basis. I would suggest those with relaxed hair co-wash maybe once a week. On relaxed hair co-washing is good for stretching time between relaxers as the conditioner will soften your roots.
While transitioning I shampooed once a week as well as co-washed once a week. This worked well for my hair and helped with blending the two textures. Now that I am completely natural depending on how much product I use I sometimes increase to two co-washes a week. Again listen to your hair. If you notice additional shedding or feel that it your hair does not appreciate it, then you should probably stop.
Some tips for co-washing:
1. Always use a cheap conditioner to co-wash. You are going to be using much more product than you would if you were just conditioning your hair. You are also not leaving it on as long as so it does not need to be thick. There are cheap conditioners that are great for co-washing. My favorite is Suave Almond & Shea Butter. I also use VO5 Moisture Milks Conditioner (generally you can get it at Walmart for less than $1)
2. Just wet your hair. Usually while I am wetting my hair I massage my scalp. Add conditioner and proceed as if you were shampooing your hair. It is also a good time to detangle your hair with a wide tooth comb while the conditioner is in your hair.
3. Rinse your hair with cold water. Cold water helps close your cuticles allowing water to remain in your hair and retain moisture. Not everybody like to rinse with cold water, but you should at least try it with the last rinse.
4. Add some leave in conditioner and style
After a few weeks you should notice a difference in your hair.