Cosmetics are designed for people's well-being, for healthy skin!
They should not have any side effects therefore ingredient-concentration is low.
The only active ingredients they are allowed to have are UV-filters. (Valid for US, AU, EU).
Ingredients classified as "not-active" are also regulated. (For ex. Vitamin C can have up to 5% concentration; as opposed to cosmeticeuticals where they can have up to 20% -must be sold through a dermatologist.)
Ingredients are only allowed to penetrate the Epidermis. They are not allowed to change the skin's functioning! Hence cosmetics can only:
Hydrate (moisturizing agents),
Protect the skin (anti-oxidants and sunscreens).
Rx Drugs are designed for specific problems related to the treatment of damaged, not correctly functioning skin. They can have adverse side-effects. Can only be sold Rx and can use ingredients classified "Active" like tretinoin, azelaic acid etc.
Pharm. Co. must refer to thorough testing and improvement in skin condition the drag is designed for.
Active ingredients allowed to penetrate through the Epidermis down to the Dermis. Hence they can alter/change the skin's functioning.
Cosmeticeuticals are a cross between cosmetics and Drugs. They still cannot penetrate deeper then the Epidermis but they are allowed to have higher concentrations of vitamins. That makes it possible that they can have some effect on the skin: protection and hydration. (Except AHAs; they increase collagen in dermis and so does Vitamin C still they are not officially acknowledged for this).
They are sold at dermatologists` offices only.
Sunscreens:
US:Are classified as OTC drugs by the FDA hence making it very difficult to introduce new effective sunscreens in the US. (16 UV-filters are in US-2 UVA).
In EU and AU they are classified as cosmetic ingredients whose maximum concentration is predetermined by law. Since they are not classified as OTC drugs, it allows new and better sunscreens to be introduced quicker to the general public. (28 UV-filters are in EU-9 UVA!).
see also:
http://ec.europa.eu/...legal_intro.htm
http://www.cfsan.fda...s/cos-hdbk.html
http://vm.cfsan.fda....d/fr990521.html
http://abcnews.go.co...story?id=858453
http://www.tga.gov.a.../sunscreens.htm