By Amy E. Feldman

PHILADELPHIA (CBS) – If a company really told you the truth about its product in its ad, you’d never buy it. But how honest does a manufacturer have to be?

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If you had to guess, if you saw an ad that said that a moisturizer was “clinically proven” to “boost genes’ activity and stimulate the production of youth proteins that would cause “visibly younger skin in just 7 days” how long before you’d expect to see results? Nope.

The Federal Trade Commission has just settled a charge with L’Oreal, in which the FTC had alleged that the ads for Youth Code products, for which the company charged up to $135, were misleading.

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But, if advertisers told you honestly what was in every product, you’d never want to buy anything ever again. So, what does the law say about how honest advertisers have to be?

The Federal Trade Commission, which protects consumers against deceptive trade practices, allows advertisers to use subjective claims or puffery – claims like “this is the best moisturizer in the world.” But if there is an objective component to the claim – such as “it targets gene activity” then advertisers have to support the claim by competent and reliable scientific evidence.

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L’Oreal has agreed to remove the false claims from its labels because like most advertising, the truth isn’t so pretty.