Crystalline, a protein found in the human eye, penetrated and repaired bleached hair, according to the results of a new study published in the International Journal of Cosmetic Science. “Bleach breaks bonds inside the hair shaft and disrupts the protective layer, making hair weaker,” says Randy Schueller, cosmetic chemist and editor-in-chief of the Beauty Brains. “Gamma crystalline [the kind tested in the study] can penetrate into the inner region of the hair shaft, allowing it to strengthen hair from within.” It also forms a film on the outside of hair, smoothing that protective layer. While products don’t currently use this technology, other proteins, like keratin and quinoa protein, have been shown to have similar effects, explains Schueller. Keep crystalline on your radar, but until it starts popping up on shelves, try a keratin-rich conditioner. We like Coppola Keratin Complex Keratin Care Conditioner ($13.40; amazon). More from Prevention: 4 Ways To Strengthen Damaged, Frizzy Hair
