The latest K-beauty craze is made from dead Americans' skin. Now it's aiming for the US.

Getty Images; Alyssa Powell/BI A hot, new beauty treatment driving tens of millions of dollars in sales around the globe is now aiming for the US market.

Its unusual ingredient: skin from dead Americans.

Each year, tens of thousands of Americans donate bodily tissue upon their deaths, generally by checking a box at a motor vehicle department or through an authorization made by a loved one.

Over the past few years, tens of millions of dollars' worth of donated skin has traveled from American tissue banks to biotech companies in South Korea, the beauty capital of the world.

There, among other uses, it is turned into injectable beauty treatments.

The maker of the market-leading Korean brand said last week it has signed a distribution contract to introduce its skin-derived injection to the US market next year.

It isn't clear whether the product can be sold in the US without approval from federal regulators.

Business Insider traced the tissue supply chain to understand how donor tissue from, say, San Antonio can end up for sale at a clinic in Seoul — and how much money is being made along the way.

People who donate tissue "have no idea of how much money is changing hands in the course of all of this," Ana Iltis, a professor at Wake Forest and former president of the American Society for Bioethics and Humanities, told Business Insider.

"With tissue donation, there's a lot of money at stake." Donors and their families can't be paid for organ or tissue donations under US law.

A K-beauty trend For decades, American plastic surgeons have used products made from human tissue for skin grafts and reconstructive surgeries.

That practice includes aesthetic uses — such as cartilage for a nose job or skin for a breast augmentation — though many doctors prefer to use the patient's own tissue for such procedures.

Now, skincare treatments made from human tissue can be purchased for a few hundred dollars and administered at a med spa or dermatology clinic in under an hour.

In South Korea, a mecca for cutting-edge beauty treatments , at least 10 biotech companies are making or planning to introduce skin-derived injections.