I have been using keratin personally and professionally for over fifteen years. Here are my observations after trying it on myself before I use it on any of my clients.
1-Product is very think and has a pleasant smell- However, despite being apply an inch away from scalp, it is very strong and can feel like it’s burning the scalp. If you’re using it right after color treatment, or on a client with high sensitivity- be mindful of this fact.
2- It might not contain formaldehyde, but If you are per...