Call it a killer tan. An underground drug is said to enhance skin color, shed pounds, and even boost your libido. But health officials say it's illegal and very dangerous!

The search for a perfect tan is common; some worship the sun, some go to tanning salons and others use self tanning lotion.

But what if you could give yourself an injection that would create a tan that would last for months and increase your sex drive?

The product is called Melanotan II and it's only sold online, but there's just one problem. 

Dr. Lisa Benest is a dermatologist who has serious concerns about Melanotan.

"It's not regulated. It's not FDA approved and the studies aren't long term enough," says Dr. Benest. "The main problem with getting a substance like Melanotan that's not regulated and you're purchasing it on the Internet, is you really don't know what you're getting."

Melanotan is a synthetic hormone that mimics a hormone in our bodies which produces a tan. When injected, Melanotan stimulates our pigment cells.

"If we are stimulating the same cells that turn cancerous in melanoma, I think the risk is very real," says Dr. Benest.

The low price, just $42 for a vial, and the claims that it'll make you thin, tan and increase your libido, have made it popular among body builders, brides and models, but Dr. Benest says you're taking a big risk.

"If we are stimulating the same cells that turn cancerous in melanoma, I think the risk is very real," says Dr. Benest.