What Is a Keratin Relaxer?

A keratin relaxer is a professional hair treatment that promises to tame frizz and encourage straight, silky locks. It works through the direct application of keratin, a natural protein. Once the protein has a chance to soak into hair strands, it strengthens them, which is believed to make blow drying and styling simpler, faster, and more effective. Keratin relaxer treatments are generally marketed as “natural,” but have been criticized by some health experts for containing potentially dangerous levels of the chemical formaldehyde. Many salons offering the treatment err on the side of safety, requiring both clients and technicians to wear safety masks during relaxer application to prevent accidental chemical inhalation.

Most popular amongst people with naturally curly or wavy hair, keratin relaxers give users' hair an easy-to-achieve, straight look. Blow drying and straightening curly hair usually requires a lot of time and product application. Keratin relaxers work to smooth or “relax” the hair, which makes everyday styling much simpler.

Most of the time, keratin hair treatments are marketed as temporary avenues to picture-perfect hair. Treatments often take several hours to apply, but results usually last for several months. In most cases, only licensed salons and specially trained beauticians can apply a keratin relaxer, and the price is usually steep.

Keratin hair treatments originated in Brazil, and are marketed as “Brazilian keratin treatments” in some places. They represent an alternative to strictly chemical hair relaxer products, in large part because keratin is a naturally derived protein compound. Most keratin treatments also contain some chemicals, however. Formaldehyde is included in the majority of keratin relaxer solutions, even if just in trace amounts.

Adding formaldehyde helps keratin relaxers work more effectively and also helps the results last longer. Keratin itself adds protein strength to hair, which has been shown to help combat frizz. Formaldehyde is believed preserve that straightness by temporarily altering the amino acid structure of the strands. The natural proteins in keratin relax the hair first, then chemical compounds work to ensure that the hair actually stays that way for the long-term.

There are a number of health concerns with formaldehyde, and critics caution against the use of keratin relaxers that contain it. Even occasional exposure can have substantial health risks, particularly if inhaled. It is possible to find formaldehyde-free relaxer products, but they often cost just as much and are not always as effective. Straightening hair is almost always easier with the use of keratin and other relaxers, but the risks should be carefully weighed against the gains.

People who pay for keratin relaxer treatments are usually encouraged to protect their investment by following certain care guidelines. Only certain shampoos should be used on treated hair, for instance. Hair dyes and chemicals like chlorine should usually be avoided, and it is often recommended that treated hair be washed only a certain number of times a week to preserve the relaxer's effects.