"Results not typical."

How often have you seen that footnote to a testimonial from someone who's shed tonnage with a new diet potion, or gained vast wealth with minimal investment? If such disclosure is in the ad at all, it may be hard to spot, even though federal guidelines require advertisers to post it "clearly and conspicuously" when the product endorser's situation is unusual.

For that matter, when was the last time you heard a news program announce that a celebrity using its airtime to tout some new device or drug is actually being paid for that purpose? The program is supposed to, according to the rules. The same batch of rules stipulates that people giving testimonials must actually be using a product when they endorse it, and that ads containing their endorsements must be pulled when their usage stops or if the product stops working for them.

Truth is, testimonials can bend the rules because the industry that hatches them is largely self-regulated, with the government stepping in to enforce what guidelines it has only after fraud has harmed the health or picked the pockets of lots of consumers.

Among entities with some power over advertisers:

The Federal Trade Commission. The FTC's Ad Practices Program is responsible for enforcing federal truth-in-advertising laws, an amalgam of statutes, regulations and guidelines covering everything from truthfulness to the use of "free." Among the rules specific to testimonials: Experts must have the credentials and expertise their endorsement implies. The FTC also says that people who, for example, lost 100 pounds with a particular product should represent what most customers will lose. Yet there's a loophole that lets advertisers put atypical users front and center — provided there's that clear and conspicuous disclosure. Weapons the FTC wields include restraining orders, fines, restitution to consumers, and litigation.

The Food and Drug Administration. The FDA sends warning letters when it finds misleading ads for prescription drugs, but it can also seize products and pursue criminal penalties. It has no guidelines for testimonials, and has a staff of just seven.

The Better Business Bureau. This private, nonprofit organization's National Advertising Division (NAD) operates a courtlike system in which anyone can challenge the veracity of national or regional ads. Participation is voluntary, and 5 percent of the challenged companies don't participate in the process or comply with a NAD decision, according to the organization.

State attorneys general and district attorneys. AGs and DAs can file charges against advertisers who violate state or local laws. On at least one occasion, an attorney general has also sued an advertiser.

To be sure, many testimonials these days do carry the "results vary" disclaimer. Yet such statements may not be enough to satisfy the FTC. The agency is rethinking its disclosure rules, and in 2006 it plans to ask the public whether changes are needed.

In the meantime, if you think an ad is misleading, file a complaint with the FTC (www.ftc.gov/ftc/consumer.htm), the NAD (www.nadreview.org), or your state attorney general (in Washington, it's www.atg.wa.gov), district attorney, or department of consumer affairs. Explain in writing why the ad is misleading, and enclose the original or copies if possible. For a radio or TV ad, name the product, the claim and where and when you saw the ad.

Copyright 2006, Consumers Union, Inc.