Looking for an effective, sustainable toothpaste? It might be on top of your head.

Scientists have discovered that keratin, a protein found in hair, skin, and wool, can repair tooth enamel and stop tooth decay. It might also protect teeth even better than conventional fluoride-based toothpastes, stopping tooth decay in its tracks, according to a new study.

When keratin comes into contact with saliva, it forms a protective coating that mimics natural enamel, the study shows. Not only can it shield teeth from further damage, but it may also help repair enamel—something traditional toothpastes can’t do.

The findings are published in Advanced Healthcare Materials. 

“Keratin offers a transformative alternative to current dental treatments. Not only is it sustainably sourced from biological waste materials like hair and skin, it also eliminates the need for traditional plastic resins, commonly used in restorative dentistry, which are toxic and less durable,” Sara Gamea, a graduate student at King’s College London and first author of the study, said in a statement.

Tooth enamel wears away with age, leading to tooth sensitivity and eventually a need for dentures. This process is hastened by acidic foods and poor oral hygiene. And once enamel is gone, it’s gone.

Fluoride toothpaste can slow this process but not stop it. What can? Keratin, apparently. The protein forms a dense crystal-like scaffold that mimics the structure, color, and function of actual enamel, the new study found.

Over time, the scaffold continues to attract calcium and phosphate ions, leading to the growth of an enamel-like coating on teeth. That means keratin-based toothpaste could potentially repair lost enamel and seal exposed nerves—reversing the symptoms of enamel erosion.

The study authors used keratin extracted from wool in their study but said it could also be extracted from other sources, including human hair. This is a huge step for regenerative dentistry, the researchers say. It’s also good for the environment, providing a biodegradable alternative to conventional toothpastes. And happily, consumers might not have to wait long to purchase a keratin-based toothpaste; the researchers say it could hit the market in the next two to three years.

“We are entering an exciting era where biotechnology allows us to not just treat symptoms but restore biological function using the body’s own materials. With further development and the right industry partnerships, we may soon be growing stronger, healthier smiles from something as simple as a haircut,” Sherif Elsharkawy, the study’s lead author and consultant in prosthodontics at King’s College London, said in a statement.