Buyer beware: Dietary supplements marketed on Web sites with claims of treating specific diseases are a scam. The latest company to admit wrong doing is Techmedica.

Since Techmedica Health, Inc., got into the supplements business, it has sold useless products to an estimated 24,000 people. The company earned $12 million dollars between 2005 and 2006 from selling worthless products on several Internet sites, products that the company fraudulently marketed as dietary supplements.

These damning facts were all admitted in the guilty plea of the company's Michigan owner Tony T. Pham on July 2, 2009. Pham agreed in court to forfeit these earnings to the government, and that's not all. He could be sentenced for up to 25 years in federal prison, as well as pay a fine of as much as $500,000.

I am encouraged by this episode, as well as by other actions recently taken by the Food and Drug Administration to curb the sales of potentially dangerous weight-loss supplements. (Read More Weight Loss Supplements Banned by the FDA.)

Brazen untruths
What exactly did Technimedica do wrong? The company's Web sites claimed that clinical testing had proven its products effective for the treatment or prevention of diabetes, gout, high cholesterol, irritable bowel syndrome, heartburn, and diarrhea. (Federal law prohibits claims that a dietary supplement can treat, cure, or prevent a specific disease or class of diseases.)

In fact, no clinical studies were ever done on the products. Instead, the company posted the picture of an attractive model from California, who posed as a fake physician who endorsed the worth of the supplements for customers with diabetes. Another Web site used a photograph of the same model as an alleged (but nonexistent) nurse, "Bethany Hunt, RN," who was prepared to swear that certain Techmedica products were effective. The company also posted photos of make-believe purchasers giving glowing testimonials regarding the effectiveness of its products.

These revelations are noteworthy for several reasons:

• Sales of dietary supplements can be quite lucrative.
• Pitchmen will go to great lengths--that is, tell barefaced lies--to sell their products.
• Many people (we might say "suckers") believe the gimmick enough to purchase the products.

No proof of supplements' health benefits
By citing the Techmedica case, I do not mean to suggest that a great many other companies use such fraudulent methods on the Internet to promote their products. Most companies that sell dietary supplements are smart enough not to make such unabashedly dishonest and illegal claims about the preventive or curative powers of their products.

However, to date, careful clinical trials have not substantiated the health benefits of the products sold by even these more scrupulous purveyors of dietary supplements.

Do the math
If we assume that each Techmedica Health customer spent $500 on their purchases (probably an overestimate) over the years the company was open for business, we can calculate that nearly 24,000 people were taken in by these advertisements ($12,000,000/$500 = 24,000). It's impossible to even guess how many people have bought other, equally ineffective, and possibly harmful supplements from other companies. (Read FDA Warning for Weightloss Supplements.)

Don't fall for this scam
I urge you to heed this advice the next time you come across a Web site selling dietary supplement products: Beware of supplements touted only in the testimonials from satisfied customers and promoting physicians, even if they happen to be real people.