Shower gel is primarily designed for the skin, not the hair. While it can technically be used on hair as a substitute for shampoo in an emergency, it is not recommended for regular use. Shower gel generally uses milder ingredients than shampoo, as it seeks to remove the natural oil from the skin, not the hair. Shampoo, on the other hand, is specifically formulated to remove excess oil from the hair while leaving some to help retain nourishment and moisture. Shampoo also contains specific conditioning molecules that cling to the hair, making it smoother and easier to brush. Shower gel, on the other hand, does not offer any protection from hair products and hair dyes, and it can strip the hair of its natural oils, weakening it. The pH levels of shower gel and shampoo also differ, with shampoos usually having a lower pH than shower gels to be closer to the natural pH of the hair shaft. If you do decide to use shower gel on your hair, it is important to choose a product that is gentle and moisturizing, pH-balanced, and to use it sparingly and only when necessary. It is also recommended to follow up with a conditioner to help hydrate and protect the hair.