Friend or Faux?

Crazy ad claims and the truth - or fiction - behind them

There's reality. There's alternate reality. And then there's marketing. When your cash is on the line, it's important to know which category an intended purchase falls under. Armed with a stack of studies and consultations with the top researchers who wrote them, we separated the scientific brilliance from the worthless bunk.

Repel Pests with High-Frequency Sound - Inaudible to People!

The Claim: "These are the most effective mosquito-control products on the market!" says one manufacturer.

The Reality: The Federal Trade Commission has accused several firms of making "unsubstantiated claims" about the ultrasonic devices.

The Real Fix: Studies show that the most effective method of warding off mosquitoes is applying DEET-based repellents. Want to keep the treatment all-natural? Try Bite Blocker (biteblocker.com), rated the most effective alternative repellent by the New England Journal of Medicine.

Swallow a Pill to Freshen Your Breath All Day Long!

The Claim: Natural oils work in your digestive system "to clean bad breath at the source."

The Reality: "Ninety percent of bad breath originates in the mouth, not the stomach," says Richard Price, D.M.D. Chewing parsley, fennel seeds, or cloves can mask odors and wash away germs with saliva, but it won't eliminate bad breath.

The Real Fix: Find a mouthwash with chlorine dioxide and zinc chloride; these can minimize stinky bacteria and neutralize sulfurous compounds. Crest's Pro-Health line should do the trick.

Brighten Your Smile - with Gum!

The Claim: "Chewing gum after eating and drinking helps fight cavities, remove food particles, and neutralize plaque acids."

The Reality: Sugar-free gum can work wonders. "The simple action of chewing increases saliva flow and raises alkaline levels, washing away plaque and neutralizing acids on the teeth," says Larry Chow, Ph.D., chief research scientist at the Paffenbarger Research Center of the American Dental Association.

Bonus: Gum with calcium and phosphate can actually fight tooth decay, says Chow. Trident contains calcium derived from milk and phosphate.

Pop a Pill to Power Up Your Penis!

The Claim: An all-natural pill "will enlarge your penis size in weeks!"

The Reality: Of the hundreds of herbal sex pills out there, "most are worthless," says Richard Brown, M.D., an alternative-medicine researcher at Columbia University.

The Real Fix: Peruvian researchers found that the herb maca increased sex drive in men after 8 weeks. And Rhodiola rosea has been shown to boost your level of nitric oxide, the chemical that causes an erection, and to quell mental fatigue, Dr. Brown says. Nothing makes your penis bigger, except puberty.

Banish Odors Forever with a Quick Chemical Spritz.

The Claim: "Unlike other air fresheners that just cover odors with heavy perfumes, Febreze seeks out and eliminates odors."

The Reality: Febreze is made up of doughnut-shaped chemical structures called cyclodextrins, which bind with odor molecules and limit their ability to foul the air, according to Isiah Warner, Ph.D., a professor of chemistry at Louisiana State University.