The secret to shinier, healthier hair may be sitting on the shelves of your local Asian grocery. Wheat gluten—a protein from wheat flour commonly used as a meat substitute—may be able to rebuild broken chemical bonds in hair protein, according to a new study. But the findings might not be so clear-cut: Other scientists want to see more rigorous testing before they’re convinced.
Human hair is made mostly of a fibrous protein called keratin. Chemical bonds stitch these proteins together, giving it strength and rigidity. In healthy hair, these bonds—known as disulfide bridges—are secure and unbroken. But daily life takes its toll: Too much exposure to sunlight and products such as bleaches, straighteners, and dyes breaks the disulfide bridges, making hair brittle.
That’s why hair care manufacturers have experimented for decades with animal- and plant-based proteins that could potentially replace the broken bonds in hair keratin. But doing so requires a tricky chemical balancing act. The building blocks of proteins, peptides, all have a pH value at which they are neither positively nor negatively charged. To promote the formation of new disulfide bonds, that value, known as the isoelectric point, has to match the pH of hair keratin. So far, no currently available products have managed this feat, says Shukun Wang, a chemist at Jiangnan University in Wuxi, China.
Wang and her colleagues wondered whether they could change a protein’s isoelectric point to make it mesh better with keratin’s pH value. For their experiment, they turned to wheat gluten, one of the most widely available and cheap sources of protein available to manufacturers. First, the researchers soaked their gluten in a solution of water and Alcalase, an enzyme that helps break down the protein into its base peptides. Next, they added this substance to a chemical soup called EDDAC, raising its isoelectric point. Finally, they incorporated the solution into a shampoo and applied it to tresses of freshly trimmed human hair, which they combed in both wet and dry conditions.
Because combing-damaged hair generates more friction than healthy hair, a machine measured friction as a proxy for damage. Compared to untreated hair from the same person, treated hair resulted in about 21% less friction when dry and nearly 50% less friction when wet, the researchers report today in Royal Society Open Science. Looking at the hair under a scanning electron microscope backed up those findings: The treated hair fibers were visibly smoother than untreated hair, suggesting that the concoction coaxed the broken-down wheat gluten to form new bonds that replaced the damaged ones, the scientists say.
Though that seems to be a reasonable conclusion, the associated statistical analyses seem “inadequate,” says Sarah Millar, a dermatologist who studies hair at the University of Pennsylvania Perelman School of Medicine, in an email to Science. The study is missing key information on what type of hair was tested, as well as how the researchers made sure the combing force was consistent across experiments.
If the results hold up, though, Millar says the technique could be a boon to customers who want evidence-based cosmetics. “If properly conducted and controlled … this research can be of great benefit to consumers in ensuring that they are purchasing products that are scientifically proven to perform as advertised.” So maybe you don’t have to be born with it, after all.