2, potato skin can really dye the hair black, but this color is attached to the surface of the hair, and the color is washed away after cleaning.

3. Because there are tyrosine and tyrosinase in potatoes, under the catalysis of this enzyme and oxygen, a reaction called browning will occur, and tyrosine will gradually become another substance, and finally these substances will polymerize into melanin. But this melanin is water-soluble, and it will come off when washed.