In a new study, scientists discovered that keratin, a protein found in hair, skin and wool, can repair tooth enamel and stop early stages of decay.

The King’s College London team of scientists discovered that keratin produces a protective coating that mimics the structure and function of natural enamel when it comes into contact with minerals in saliva.

Dr. Sherif Elsharkawy, senior author and consultant in prosthodontics at King’s College London, said, “Unlike bones and hair, enamel does not regenerate. Once it is lost, it’s gone forever.”

Acidic foods and drinks, poor oral hygiene, and aging all contribute to enamel erosion and decay, leading to tooth sensitivity, pain and eventually tooth loss.