Marathon runner Kaysee Bentley from Alisa Viejo used to be a skeptic about the band she wears on her wrist.
"I didn't really believe it. I mean, a bracelet really affecting you that much didn't seem like it could happen," said Bentley.
But she says something did happen. In three months, she says she went from a 9-minute mile to an 8-and-half-minute mile.
The company claims the embedded holograms on the wristbands, which sell for $29.95, are tuned to the body's natural frequency and gives people a biological boost. But despite the all-star testimonials, the Australian Competition and Consumer Commission didn't see any science, and said the company had no right to claim they improved performance.
"The problem is that when you look at the actual scientific evidence of that, we're not seeing that yet," said Dr. Ralph Gambardella, sports medicine specialist at the Kerlan-Jobe Orthopaedic Clinic in Los Angeles.
He says the true power behind these bands is the power of belief.
"The placebo effect can be extremely important and it's not something that we want to shun, but that does not mean that it is evidence-based," said Dr. Gambardella.
Power Balance ended up admitting that they had no credible scientific evidence to back up their claims. The company also agreed to refund customers who believed they were misled. And they took the phrase "performance technology" off their website.
"While our previous claims in marketing ads are not up to Australia's ACCC standards - we stand behind our products," the company said in a statement.
Dr. Gambardella says your mind may be the most powerful tool of all.
"Performance is clearly tied to your own level of mental balance," he said.
A spokesperson for Power Balance said they don't claim to have science on their side, but rather rely on testimonials from athletes, some of whom are paid for the rights to use their image. The company said it is committed to further evaluating the product's performance parameters.
The company sold $8,000 of merchandise in its first year and expects more than $35 million in sales in 2010.