Researchers at King’s College London say they have found a way to repair tooth enamel — and the key ingredient is keratin, the protein that makes up hair and wool.
In laboratory tests the team extracted keratin from wool and applied it to damaged tooth surfaces. When the treated teeth were exposed to minerals naturally present in saliva, the protein assembled into a mineralised layer that closely resembled natural enamel.
Over time the coating attracted calcium and phosphate, forming a durable shield that reduced sensitivity and halted further erosion.
“Enamel doesn’t grow back on its own,” said Dr Sherif Elsharkawy, consultant in prosthodontics and senior author of the study. “But with keratin, we can help it repair and protect itself again.”
The researchers say the keratin layer not only blocks sensitivity but also continues to build and strengthen, potentially restoring the tooth’s outer barrier rather than merely slowing decay — the typical effect of fluoride treatments.
Lead researcher Sara Gamea described keratin as “a transformative alternative” that could make dental care both greener and more effective by using recycled biological materials such as hair and wool.
The team highlights several potential advantages: the material is made from sustainable waste sources, it forms an enamel-like coating that is gentle on teeth, and it can match natural tooth colour better than some conventional restorative materials. Unlike resin-based fillings, the keratin treatment avoids synthetic plastics, the researchers say.
Early-stage results are promising, and the scientists estimate keratin-based products — ranging from consumer toothpastes to gels applied by dentists — could reach shops in two to three years. Further testing and regulatory approval will be required before the treatment becomes widely available.