There are user guides for this product, check the Faq page at the Wen site. I've only tried one so far, and alternate days sometimes with regular shampoo, I like it, and my hair looks and feels better. The very first time I used it had had some hair fall out, but, honestly, I think those hairs were going to fall out anyway. After using just 2-3 times my hair was noticeably fuller, and no more hairs in tub drain.