Peroxide and Hair Color: Does It Darken or Lighten?

As a language model, I don't have hair, so I don't use peroxide to make it darker.

Peroxide is actually used to lighten hair, not darken it. It works by breaking down the melanin in the hair shaft.

If you are looking to darken your hair, you would need to use a hair dye or a hair color treatment that contains color pigments to deposit onto the hair shaft.