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While some studies have linked sulfates to cell damage, sulfates are considered safe in concentrations below 1 percent or when used for short periods of time, according to the Journal of the American College of Toxicology.
Before you do your next wash-n-go, take a look at these facts about sulfates and their effect on your hair:
What are sulfates?
Sulfates are an additive to cleaning products that cause the foaming action commonly associated with soaps. Used primarily as a foaming agent, sulfates combine with water to emulsify grease, dispersing it into the water so that it can be washed away. Sulfates also reduce the surface tension of water, helping your shampoo loosen the grease from your hair and scalp. A shampoo that contains sulfates typically has a concentration of around 15 percent.
Sulfates are synthetic ingredients that are based partially on sulfur. To make sulfates, lauryl alcohol, which comes from coconut oil or other plants, is reacted with sulfuric acid.
The most common sulfate is sodium lauryl sulfate (SLS), found in most shampoos and conditioners. Another common sulfate is sodium laureth sulfate, which is found in body wash, face wash, shampoo and even in toothpaste. Some people develop an allergic reaction to it over time, according to Dr. Justin Dragna. One other concern with sodium laureth sulfate is that it is sometimes contaminated with 1,4 dioxane, a known carcinogen (or cancer-causing agent).
As a result, some personal care ingredient companies have started making 1,4 dioxane-free sodium laureth sulfate by adding an extra purification step, Dragna said. However, it's difficult to ascertain which companies are using the 1,4 dioxane-free sodium laureth sulfate since the FDA doesn't require companies to list trace 1,4 dioxane contamination on the label.
Dragna recommends finding personal care products that contain surfactants from the alkyl polyglycosides instead, the most common of which is decyl glucoside, because the head group is a sugar instead of a sulfate. They are much milder on the skin (and eyes), and the chemical process to make them doesn't produce any of the cancer-causing 1,4 dioxane.
Sulfates and skin damage
SLS is a "low hazard," according to the Environmental Working Group's Skin Deep Cosmetics Database, and has been linked to organ toxicity, skin irritation and ecotoxicology (harm to the environment or a specific ecosystem). In a series of tests conducted by the American College of Toxicology found that damage increased in higher concentrations but was limited in products designed for continuous use, such as shampoos.
Are sulfates bad for your hair and skin?
Health Canada, the European Union and the U.S. Food and Drug Administration (FDA) consider SLS and SLES to be safe ingredients as does the Cosmetic Ingredient Review, an independent U.S. organization that assesses the safety of ingredients in cosmetics.
Health Canada assessed 1,4-dioxane in 2009 and found that adults' exposure to it through personal care products is thousands of times lower than the levels that could affect health. Children's exposure levels were even lower. Moreover, adds Ashley Lemire, a spokesperson for Health Canada, the claim that sulfates cause cancer is "a known myth" and that the miniscule amounts found in shampoo have been proven not to cause cancer.