Chemicals?

School me brehs.
Most of them contain harsh detergents and shyt like that which can irritate the skin, and, in terms of shampoo, can help assist towards hair loss.
Stay away from SLS chems and anything of the matter. In fact, if you can, make your own soap. Otherwise, buy all natural. Soap boxes with no labels are typically tell-tale signs of chemical soaps so find a local dealer who makes 'em and check it out.
I myself use a soap based aloe, glycerin, and an essential oil of my choice depending on what I need out of the soap.