I have fine strand hair that responds well to protein treatments. While I do heavy protein treatments occasionally, I like the fact that GPB is a light protein treatment that gently fortifies the hair while still being moisturizing and hydrating. This is NOT vegan, as it does use milk protein. It is also one of the few Aubrey products that is not scented if scent is an issue for you (if you prefer a scented version they have introduced a Rosemary Peppermint GPB as well as a Lavender Ylang Ylang GPB).