A federal agency has said that 20 percent of dietary supplements have false claims.

The report by the Department of Health and Human Services said that in a study of 127 dietary supplements samples, that promised either weight loss or improved immune system, about 20 percent made false claims on their labels.

Dietary supplements, especially those marketed under weight loss, are a fast growing market with a worth of about $20 billion per year in the U.S. About 80 percent of adults in the U.S use dietary supplements. The new report suggests that most of the claims made by the manufacturers of these supplements may be misleading.

The report also found that 7 percent of the studied dietary supplements samples did not carry a disclaimer on them. By law, the supplements should carry the following disclaimer "This statement has not been evaluated by the Food and Drug Administration.  This product is not intended to diagnose, treat, cure, or prevent any disease."

"Consumers rely on a supplement's claims to determine whether the product will provide a desired effect, such as weight loss or immune support.  Although supplement manufacturers' use of structure/function claims has grown, FDA's authority to monitor such claims remains limited by law," the report said.

Handwritten College Term Paper Says the Product Works

When researchers reviewed documentation about the claims regarding the dietary supplements, they found that about 10 percent of the substantiating documents submitted by the manufacturers did not comply with the FDA guidelines. For example, one company submitted a 30 year old hand written term paper as proof that their product works while some others gave links to some websites and to Wikipedia that backed up claims for their supplements.

The Department for Health and Human Services Inspector General's report recommended that the FDA be given authority to check the claims of the dietary supplements and that the agency should include these dietary supplements in its market surveillance to detect false claims.

According to National Center for Complementary and Alternative Medicine, a dietary supplement manufacturer does not have to prove the safety or the efficacy of the product before marketing so people planning to get these supplements must get information from reliable sources. Also, these supplements might interact with other prescription pills that you are taking.