Hair can be naturally darkened with strong, black coffee. According to Whole Magazine, darkening hair with coffee is significantly less damaging than using chemical-based hair dyes.Know More
The easiest way to use coffee to darken hair is to brew a strong pot of coffee and let it cool down completely. Completely saturate hair with the coffee brew. Let it sit for a few minutes before washing out. Repeat the process until desired color is achieved. Wash hair with regular shampoo and conditioner after dying it with coffee. Maintain naturally darkened hair by repeating the process once a week. Black tea and black walnuts are also ideal hair darkening alternatives to chemical dyes.