The FDA announced Wednesday it had issued a warning letter to the product's manufacturer, Melanocorp Inc. of Hendersonville, Tenn., for the illegal sale and marketing of the product that isn't FDA-approved.

"This product is being mislabeled, marketed and sold illegally as a preventative against skin cancer and as a tanning agent," said Dr. Steven Galson, director of the FDA's Center for Drug Evaluation and Research.

Melanocorp Inc. advertises the product on its Web site as an injectable tanning product that is effective in protecting against skin cancer and rosacea, a condition that causes a flushing and redness of the skin, the FDA said. Officials said the introduction and delivery of Melanotan II into interstate commerce violates federal law.

The FDA cautioned consumers about injecting any substance, particularly products that aren't FDA-approved, into their bodies without the oversight of a licensed healthcare provider.

Consumers and healthcare providers were urged to notify the FDA about complaints or problems associated with the product.