If you've considered lightening your hair but aren't sure which color is right for you, lemon juice may be the answer. Lemon juice permanently lightens hair when it's exposed to ultraviolet light from the sun. The effect is gradual, so you can use it several days in a row until you achieve the perfect shade. What's even better is that the color easy to maintain as your hair grows, since the difference between your roots and the rest of your hair will be subtle. As with any hair color treatment, the result depends on your original hair color, so if your hair is red, for example, you can expect it to turn strawberry blond.