Sulfates in Shampoo: Should You Avoid Them?

13 May 2019

Ever wondered why shampoo quickly turns into foam when mixed with water? The answer is the inclusion of chemical foaming agents like sodium laureth sulfate (SLES) and sodium lauryl sulfate (SLS).

While some studies have linked sulfates to cell damage, sulfates are considered safe in very low concentrations or when used for short periods of time, according to the Journal of the American College of Toxicology. However, frequent use of products with a high concentration of sulfates has been linked to cell damage and excess stripping away of natural oils and hair proteins. From a hair care perspective, this definitely isn’t a good thing.

What Are Sulfates?

Sulfates are a common ingredient in lots of cosmetic and cleaning products, including your shampoo and conditioner. A sulfate combines with water to emulsify grease, dispersing it into the water so that it can be washed away. Sulfates also act as a surfactant, a substance that reduces the surface tension of water, helping your shampoo loosen the grease and sebum, your natural oil, from your hair and scalp.

This is both good and bad. Sulfates are “good” in the sense that they make shampoo far more effective. However, they’re bad in the sense that they can have too much of an effect on your scalp and hair, resulting in excess stripping away of naturally occurring proteins and oils.

Sulfates and Hair

Hair is made of protein -- in fact, hair itself is a protein filament. About 91 percent of each of your hair fibers is protein, along with numerous other nutrients. When the protein that makes up each of your hairs is damaged, it can weaken the hair, affecting its strength and appearance, leading to split ends, breakage, and hair that is difficult to manage.

If you dye your hair, sulfate-free shampoos can also help maintain your color, which can be stripped by the detergent in a shampoo that contains sulfates.

Sulfates and Skin

If you have particularly sensitive skin, sulfates may increase your sensitivity, potentially causing damage to your skin when overused, resulting in an irritated, flaking and itchy skin and scalp.

Sulfate-free shampoos don't foam and lather like a traditional shampoo, an aesthetic difference that accounts for the widespread use of sulfates in cleaning products. Rest assured, however, that despite the reduced lather, your sulfate-free shampoo is still doing its job.

Sulfates and Cancer Risk

Sulfates have been rumored to be carcinogenic, but this myth is unfounded. The SLES and SLS in your shampoo have no carcinogenic properties, according to the American College of Toxicology and the Cosmetic Ingredient Review expert panel, which revisited the compound in a safety assessment conducted in 2002.

Sulfates in Shampoo: Should You Avoid Them?

"Though sulfate-based shampoos do effectively clean the hair, they can also strip the hair of essential oils as well as irritate the skin," cosmetic chemist and BeautyStat founder of Ron Robinson told Glamour. So it’s best to stick to sulfate free shampoo to ensure a happy and healthy head of hair.

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