What Is Sulfate-Free Shampoo — And Do You Actually Need to Use It?


In recent years, sulfates have come under fire for being harsh on the hair and scalp, stripping hair of color, and dulling shine. But are they really to blame?

Every shampoo formula contains at least one kind of cleansing ingredient to help wash away dirt and sebum from the scalp. Sodium or aluminum lauryl sulfate (SLS or ALS) and sodium laureth sulfate (SLES) are common sulfate surfactants used in shampoo formulations.

At the molecular level, these cleansers, called surfactants, are multitaskers. Due to their unique chemical nature, when dissolved in water, they assemble into groups called “micelles,” which have the ability to surround and lock in the oils in sebum and keep them suspended in water. Surfactants are also responsible for the foaming action which makes showers more pleasurable, but also “thicken” the water (à la whipped cream) so we can work it into hair instead of it slipping through our fingers.

So are sulfates bad for your hair?

In the Good Housekeeping Institute Beauty Lab, we have evaluated many shampoo formulations both with and without sulfates on hundreds, if not thousands, of testers over the years. Shampoo formulations from reputable brands are overall well-tolerated: We haven’t had a single tester drop out of a study because they found the formula to be harsh.