Since Nair is a hair remover, it can technically be used to remove hair from the head. However, this is not the product's primary use. Nair works by using strong chemicals to dissolve the hair, which is then washed away.
Using Nair on the head has more potential to work if the hair is very short, similar to the length of leg hair. It is important to note that the chemicals from this product can cause irritation, red bumps or rashes or otherwise affect sensitive skin. This product is for external use only and should not enter your eyes, nose or mouth.