The cosmetic company Lush makes natural henna-based products to color hair, and they are made only from plant materials. They come in four shades, and the darkest are Caca Noir Mama (almost black) and Caca Brun Mama (dark brown). The Lush website describes the products, and there are reviews on Makeup Alley and maybe on Amazon. I tested Brun on a hair sample, and it turned my medium brown and grey hair a very dark brown with no red. To get the product, I had to order it from the website. Because it was the wrong color for me, Lush let me return the unused portion.
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