Researchers say human hair could soon be key to repairing teeth damaged by cavities

A team of scientists in London may have found a way to repair tooth enamel using an ingredient found in an unexpected place: human hair.

Researchers at King's College London experimented with keratin, the same natural protein found in hair, skin and nails, on teeth. In lab tests, the system "has shown potential in repairing early defective dental enamel lesions, restoring both optical appearance and mechanical properties," potentially offering a future in reversing cavities.

Daily habits like sipping acidic drinks or skipping proper brushing gradually erode enamel, causing sensitivity and tooth loss, the study explains. While fluoride can only slow the damage, the keratin-based formula in the new study stopped it entirely in lab tests.

Researchers harvested keratin from wool, and found that it forms a crystal-like structure upon application to the tooth surface and exposure to minerals in saliva.

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Over time, this structure attracted calcium and phosphate and turned them into a durable layer that mimics enamel. By forming a dense mineral layer that seals nerve pathways, keratin shields teeth from further wear and relieves sensitivity at the same time, the study found.

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According to the research team, the regenerated material could protect teeth against further acid wear, and the process might even reverse early decay.

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What makes the discovery especially appealing is its potential for sustainability, the researchers say. Keratin can be harvested from hair or wool that would otherwise be discarded, turning waste into a valuable health product.

In the press announcement, King's College London scientists said they envision it being added to everyday toothpaste or used in dentist-applied treatments within the next few years, though that depends on further testing and commercial development.

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Experts caution that this breakthrough is still in its early stages.

"Only limited enamel thickness was regenerated, along with questionable biocompatibility," the study notes, adding that "the clinical applicability of this technique is challenging due to the complicated fabrication process."

That means questions remain about the "scalability" of the solution in widespread application.

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According to the researchers, more work is needed to understand how thick and durable the new enamel layer can become and whether it can withstand years of real-world wear.

Independent dental scientists have also noted that lab-based enamel regeneration studies often struggle to match the complexity of true enamel.

Enamel is the hardest substance in the human body, but it can't naturally regrow once it's damaged. Traditional toothpastes and fluoride treatments only help slow decay or strengthen what's left. If the keratin-based method proves effective in people, experts say it could mark a major step toward truly regenerative dentistry.

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The study was published in the journal Advanced Healthcare Materials.