What is Sulfate-free Shampoo: Myth or Must?

What is Sulfate-free Shampoo: Myth or Must?

Published on September 27, 2024 — 8 min read

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In the constant quest for professional hair products that are good for us, or at least not bad for us, there’s a lot of chatter about dangers both real and imagined. Sulfates are one of those things causing alarm, and shampoo has gone from bathroom staple to chatroom drama. How complicated are the risks when we simply want clean hair?

What are sulfates anyway?

Put simply, sulfates are what make shampoo sudsy when you lather on a hair product. Technically, they are a type of surfactant (a term for various detergents, emulsifiers, and foaming agents that reduce the surface tension of water) that attracts both oil and water. SLS (sodium laureth sulfate) is a synthetic detergent that is both water-loving and water-hating – water-hating to attach to the oils and greases to be removed, and water-loving so it can be rinsed off easily. SLS is excellent at both, which makes it so popular with manufacturers.

The three sulfate compounds most commonly used by the beauty industry are sodium laureth sulfate, sodium lauryl sulfate, and ammonium laureth sulfate. Each type is different in intensity – the “-eth” versions are milder than the “-yl” version, and the ammonium version is milder than the sodium version – but all of them can be irritating to sensitive skin and hair. Using products with coco betaine (a surfactant derived from coconut oil) is a sulfate-free option, and though somewhat milder, it is still a detergent.

The downside of sulfates is that they can also strip natural oils from the scalp and hair removing natural moisture, which can make hair dry and brittle. And if your scalp is sensitive, sulfates can cause irritation like redness, dryness, and itching for many hair types.

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, although any concentration over 2 percent will cause some degree of skin irritation. But, a sulfate shampoo typically has a concentration of around 15 percent. Most shampoos are packed with conditioning agents to buffer the drying effects of detergent.

People with dry, dyed, frizzy or kinky or otherwise fragile hair should seriously consider ditching sulfates because they’re pretty harsh cleansers. Sulfate-free shampoo and cleansers better maintain the natural oils which help maintain hair moisture more effectively. Avoiding sulfates might also cut down on scalp irritation. And if you use keratin treatments, shampooing three times with a sulfate-based formula is enough to undo the results. Curious about bringing added moisture back into your hair? Check out our thoughts on using a leave-in-conditioner!

The lather you get from a shampoo with a sulfate – like so many modern conveniences – is designed so that you don’t have to work hard to cleanse your scalp. Products without sulfates mean massaging more rigorously to get clean – less sudsing and more scrubbing.

According to the AAD (American Academy of Dermatology), reports link sodium laureth sulfate and sodium lauryl sulfate to contact dermatitis in some people. For that reason, people with eczema or sensitive skin may not be able to tolerate them. There is no scientific evidence that the “sulfate-free” component makes shampoo gentler than other shampoos that contain sulfates. Many people have an allergy to sodium laureth sulfate or sodium lauryl sulfate, and sulfate-free shampoos can be beneficial. 

Does Sulfate Cause Hair Loss?

Most of the time, hair loss is a gradual process due to genetics, but not when it occurs suddenly or progresses rapidly. This most often occurs because of stress, a medical condition or, “improper use of shampoos containing SLS,” according to the NTEF (National Toxic Encephalopathy Foundation). Hair loss can be the result of poor rinsing that deposits SLS in hair follicles that penetrate the scalp and corrode the follicle. MaximumHair.com reports that SLS also slows the rate of new hair growth by about eight times slower than normal.

How toxic depends on how much.

It is important to remember that the toxicity of a consumer product is dictated by the formulation as a whole, not by the toxicity of an individual ingredient. This means that while raw SLS is toxic, formulations that contain diluted or lesser concentrations of SLS are not necessarily so. However:

While it is rare that consumers are exposed to SLS in its pure form, workers in manufacturing plants where products often are. The NIOSH (National Institute of Occupational Safety and Health) a division of the CDC (Center for Disease Control) cautions that SLS – and its relatives, sodium dodecyl sulfate, lauryl sodium sulfate, and dodecyl sodium sulfate – is combustible with irritating or toxic fumes in a fire; may cause a sore throat and cough if inhaled; can cause nausea and vomiting if ingested, and advises wearing protective gloves and safety goggles to avoid redness and pain. They also say it is toxic to aquatic organisms and strongly advise that it not enter the environment.

But don’t believe everything you read.

According to the NCBI (National Center for Biotechnology Information), part of the NLM (United States National Library of Medicine) and a branch of the NIH (National Institutes of Health), Reports that SLS is a potential carcinogen are false. SLS is not listed as a carcinogen by the International Agency for Research on Cancer (IARC); U.S. National Toxicology Program; California Proposition 65 list of carcinogens; U.S. Environmental Protection Agency; and the European Union.
The Center also vouches for the biodegradability of SLS (the ability of a chemical to decompose into simple, nontoxic components within a short period of time, typically 96 hours). SLS is readily biodegradable under aerobic and anaerobic conditions and, therefore, does not persist in the environment. Through the processes of oxidation, degradation, and mineralization, the decomposed by-products of SLS are benign.

We hate to burst your bubbles, but…

In time, it may be difficult to find a traditional shampoo made with sulfates as haircare companies wise up and move on. But beware of wolves awash in bubbly sheep’s clothing, or harsh detergents disguised in mild language.

To be truly safe and respectful of the body’s natural intelligence, steer clear of detergent entirely

Oil-based cleansing, using argan, coconut, or essential oils, has been the preferred method for skincare for years now, and the tide is turning for hair. Try Hairstory New Wash which substitutes essential oils and good fats for detergent, an innovation that results in never needing conditioner since it moisturizes while it cleanses. The people at Crude personal care products sums it up this way: “Sudsing cleansers have only been the norm in human hygiene for the last century — before the industrial revolution, humans cleansed primarily with natural ingredients like water, oil, and clay.” It seems like the time for another revolution.

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