Question: is 10 volume developer bad for hair?
Answer: This kind of chemical burn is very painful. Developer contains hydrogen peroxide. 10 volume contains 3% H2O2 (hydrogen peroxide) 20 volume 6%, 30 volume 9%, and 40 volume 12%. 40 volume should only be used by trained stylists, as it can damage the hair quite easily and oxidize (burn) the skin in seconds.