Yes, hair dye can be used on a beard, but it is important to use a product specifically designed for facial hair. Facial hair is coarser and more sensitive than the hair on your scalp, so regular hair dye can cause irritation, dryness, and even chemical burns on your skin.
When choosing a hair dye for your beard, make sure it is a semi-permanent or temporary hair dye, as permanent dyes can be too harsh for facial hair. It is also important to patch test the dye on a small area of skin before applying it to your entire beard to ensure that you are not allergic to the product.
Before applying the dye, you should thoroughly clean your beard and make sure it is dry. Apply the dye according to the instructions on the package, and make sure to leave it on for the recommended amount of time. After rinsing out the dye, you should apply a conditioning treatment to help hydrate and soften your beard