The chemicals and synthetic emulsifiers that are used in so many cosmetics found on the market today hold water and oil together, but they don't penetrate the skin. Unabsorbed substances leave a film on the surface of the skin which clogs pores, affects the skin's ability to absorb or eliminate, attracts dirt, and requires harsh soaps to remove.
Sodium lauryl sulfate, a chemical detergent, can cause dermatitis, and can damage your skin, hair, and eyes. Propylene glycol is a petroleum product which is used in antifreeze and hydraulic brake fluid. It can cause allergic reactions.
Many chemical ingredients used in commercial cosmetic products are on the FDA’s list of suspected carcinogens (mineral oil, propyl alcohol, TEA, PEG-8, polysorbate 80, to name a few).