Hair straightening treatments, though pricy (up to $400 a pop), are a worthwhile investment for those with genetically curly hair craving sleeker, frizz-free strands. But chemical versions, such as the Japanese (which permanently straightens) and Brazilian (which eradicates frizz and loosens curls for up to six months) treatments, have recently taken some heat because they rely on ingredients such as sodium hydroxide (called lye)—a corrosive active ingredient also found in many household detergents—and formaldehyde. The former rearranges the DNA makeup and pH levels of natural kinks while the latter helps bind keratin (a naturally-occurring protein) to hair. Both have been linked to cancer and lung damage. And, over the long run, continually relaxing hair with these methods can even lead to alopecia, a condition in which hair follicles become damaged beyond repair and fall out, never to grow back.“Disulfide bonds are the strongest bonds in hair,” says Melissa Harvey, a New York-based consulting trichologist (hair scientist) with hair growth company Bio Follicle. “They can only be broken by a radical chemical swell.”

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Since the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) issued a hazard warning in 2011 for salon employees and owners performing these types of straightening treatments, product manufacturers have raced back to their labs in search of newer, healthier straightening formulas. Zerran RealLisse uses a completely edible—yes, edible!—combination of wheat, corn and oat proteins to smooth hair for two to four months. Though the professional system is used in high-end salons including the Fred Segal Salon in Santa Monica, C.A, the company has also created a line of shampoos and conditioners with similar ingredients to help clients maintain their straight strands right at home. Farouk Systems’ Chi Enviro American Smoothing Treatment is another pro-straightening alternative that propels proven strengthening ingredients including amino acids, proteins, silk fibers and pearl into the hair’s cuticle to rearrange unruly hair strands for as long as four months. And the Anevolve Control Zero Straightening System, which grows out after one to four months, relies on sodium sulfite (a food-grade preservative) instead of formaldehyde to break down the natural bonds in curls.

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