When you chip a tooth or drink one too many sodas, your enamel — the glassy shield that protects your teeth — doesn’t grow back. Dentists can patch the damage with resins or crowns, but the original structure is gone for good.

A team of scientists at King’s College London thinks there might be another way. They’ve found that keratin — the same protein that makes up hair, skin, and wool — can be coaxed into rebuilding tooth enamel. In other words, in the future, a toothpaste made from your own hair clippings could restore teeth to their original strength and shine.

How Hair Turns Into Tooth

In their experiments, the researchers extracted keratin from wool, though human hair works just as well. In water, the keratin molecules naturally assemble into tiny fibers and spherulites. These are structures that, under a microscope, resemble snowflakes. When this protein matrix is exposed to calcium and phosphate, minerals found in saliva, it acts like scaffolding for new crystals of hydroxyapatite (the mineral that makes up tooth enamel).

Over time, these crystals align into dense, enamel-like layers. “Keratin offers a transformative alternative to current dental treatments,” said Sara Gamea, the study’s lead author. “Not only is it sustainably sourced from biological waste materials like hair and skin, it also eliminates the need for traditional plastic resins, which are toxic and less durable.”

Laboratory tests showed that keratin films could infiltrate early enamel lesions, such as those faint white spots that signal decay, and trigger new mineral growth throughout the damaged area. Within weeks, the treated enamel regained much of its hardness and structural order, far outperforming conventional resin infiltration.

Beyond Fluoride

Fluoride toothpastes slow enamel loss, but they can’t rebuild what’s gone. Keratin appears to go further, creating a “highly organised, crystal-like scaffold that mimics the structure and function of natural enamel,” according to the researchers. And this scaffold doesn’t just cover the surface. It seeps into microscopic pores, sealing off nerve channels that cause sensitivity and toothaches.

In cross-section, the repaired enamel showed prisms of hydroxyapatite tightly integrated with the original tooth structure, much like the architecture of healthy enamel. Mechanical testing confirmed the repair was more than cosmetic: hardness and elasticity rebounded to near-normal levels.

Dr. Sherif Elsharkawy, the study’s senior author, sees this as part of a broader shift in dentistry. “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,” he said.

Previously, researchers at King’s College London and Imperial College London developed a material that allows tooth stem cells to “talk” to each other. That study opens the door to regenerating teeth grown from a patient’s own cells. Elsewhere, at Tufts University, USA, researchers essentially grew human-like teeth in pigs, which might one day replace medical implants.

From Salon Floor to Sink

The keratin gel could be applied in a dental clinic, like a protective nail varnish, or incorporated into an everyday toothpaste. Because hair and wool are abundant waste materials, the supply would be sustainable. The process avoids harsh chemicals, relying on water-based preparation and the body’s own mineral resources.

The team hopes to bring keratin-based products to the public within two to three years, pending further trials. If successful, your next dental check-up might start with a trim and perhaps end with a stronger smile.

The findings were published in Advanced Healthcare Materials.