The Washington Times discusses cosmetic labeling in an article aimed towards the consumer:
Skin care, of course, embraces many problems and products, with the latter overseen by the U.S. Food and Drug Administration only when the skin’s physical structure is likely to be changed dramatically in some way by application. Most cleansers and moisturizers are over-the-counter offerings that do not require FDA pre-market approval, but by law ingredients must be named and listed in descending order of quantity.
However, that doesn’t tell a customer which ones are the most effective — to learn when quality trumps quantity. And such formulations — the various manufacturers’ mixtures and methods — generally are patented. Only a research chemist knows for sure what works best and why.