Sulfates are probably the most argued-about ingredients in personal care products. “Sulfate-free” has become a major marketing claim on shampoo bottles, body washes, and toothpastes. Some people swear that cutting sulfates changed their hair. Others think the whole thing is overblown. And most people have no idea what sulfates actually are or why they should (or shouldn’t) care. Learn more in our explainer: what is triclosan?.

The truth sits in a less exciting middle ground than either side suggests. Sulfates have real drawbacks that matter for certain people and certain uses. They also have a contamination problem that gets less attention than the ingredient itself. And the “sulfate-free” label doesn’t automatically mean a product is safer. See our top picks in best non-toxic perfume and clean fragrance.

According to NonToxicLab, the sulfate question is worth understanding properly because it affects how you choose products across multiple categories.

Let’s sort through the actual science.

What Sulfates Are

Sulfates are a class of surfactants, which are chemicals that lower the surface tension between two substances (like oil and water). Surfactants are what make cleaners clean and soaps lather. They grab onto oil and dirt on one end and water on the other, allowing the grime to be rinsed away.

The two sulfates you’ll see most often on ingredient labels are:

Sodium Lauryl Sulfate (SLS) is a strong surfactant derived from lauric acid, which typically comes from coconut oil or palm kernel oil. It’s the more aggressive of the two, creating a thick lather and providing strong degreasing action. You’ll find it in shampoo, toothpaste, body wash, dish soap, laundry detergent, and even engine degreasers.

Sodium Laureth Sulfate (SLES) is a modified version of SLS that has been through a process called ethoxylation, which makes it milder on skin. It still lathers well and cleans effectively, but causes less irritation. It’s the more commonly used sulfate in personal care products.

Both are among the most widely used surfactants in consumer products worldwide. They’re cheap, effective, and create the foamy lather that consumers associate with cleaning power.

A Quick Chemistry Note

The name “sulfate” refers to the sulfate group (SO4) in the molecule’s structure. These aren’t the same as sulfur or sulfites (found in wine and dried fruit). The chemical structures are different, and they behave differently in the body. If you have a sulfite allergy, it doesn’t necessarily mean you’ll react to sulfates.

Where You’ll Find Sulfates

Sulfates show up in far more products than just shampoo:

  • Shampoo (the most discussed use)
  • Body wash and shower gel
  • Facial cleansers
  • Toothpaste (the foaming agent)
  • Hand soap
  • Dish soap
  • Laundry detergent
  • Household cleaning products
  • Bubble bath

The concentration varies by product. Shampoo typically contains 10-25% SLS or SLES. Toothpaste contains 1-2%. The higher the concentration and the longer the contact time, the more relevant the potential for irritation.

What the Science Says About Safety

This is where the conversation gets complicated. Let’s separate the confirmed concerns from the myths.

Confirmed: Skin and Scalp Irritation

SLS is a known skin irritant. In fact, it’s used as a positive control in dermatological patch testing precisely because it reliably causes irritation. At the concentrations found in shampoo and body wash, it can strip natural oils from the skin and scalp, leading to dryness, flaking, and irritation.

SLES is milder but can still cause irritation for people with sensitive skin, eczema, or dermatitis. The ethoxylation process reduces but doesn’t eliminate the irritation potential.

For the average person with healthy skin, the brief contact time of a shampoo rinse-off product may not cause noticeable issues. But for people with dry scalps, color-treated hair, curly or textured hair, eczema, rosacea, or other skin sensitivities, sulfates can be genuinely problematic.

Confirmed: Hair Damage for Certain Hair Types

Sulfates strip oils effectively, which is a problem for hair types that need those oils. Curly, coily, and textured hair is naturally drier because the scalp’s sebum has a harder time traveling down the hair shaft. Sulfates remove whatever oil does make it down, leaving hair dry, frizzy, and prone to breakage.

Color-treated hair also fades faster with sulfate shampoos because the strong surfactant action strips color molecules along with dirt and oil.

The 1,4-Dioxane Contamination Problem

This is the concern that deserves more attention than it gets. The ethoxylation process used to make SLES can create a byproduct called 1,4-dioxane. The EPA classifies 1,4-dioxane as a likely human carcinogen based on animal studies showing liver tumors.

The critical point: 1,4-dioxane is a contaminant, not an ingredient. It won’t appear on any label because it’s not intentionally added. It’s a trace byproduct of manufacturing. The only way to know if a product contains it is through independent testing.

Dr. David Andrews, a senior scientist at the Environmental Working Group, has written extensively about 1,4-dioxane contamination in household products. His research has documented that while the levels found in individual products may be low, the concern is cumulative daily exposure from multiple products that all contain ethoxylated surfactants, including your shampoo, body wash, dish soap, and laundry detergent.

A 2021 report by Valisure, an independent analytical laboratory, found 1,4-dioxane in dozens of personal care and cleaning products, some at levels above the FDA’s suggested limit of 10 ppm.

Not Confirmed: Cancer From Sulfates Themselves

SLS and SLES are not classified as carcinogens by the IARC, NTP, or EPA. The persistent internet claim that SLS causes cancer has no scientific support. The Cosmetic Ingredient Review (CIR) panel has reviewed SLS and SLES multiple times and concluded that they are safe at the concentrations used in cosmetic products, with the caveat that they can be irritating.

The cancer concern is specifically about 1,4-dioxane contamination in SLES, not about the sulfate molecule itself.

Not Confirmed: Endocrine Disruption

SLS and SLES do not appear on any major list of endocrine-disrupting chemicals. Dr. Shanna Swan, whose research on endocrine disruptors in personal care products is among the most cited in the field, focuses her concerns on phthalates, parabens, and bisphenols rather than sulfates when discussing hormonally active chemicals in personal care products.

SLS vs. SLES: The Differences That Matter

FactorSLSSLES
Irritation potentialHigherLower
Cleaning strengthStrongerComparable
1,4-dioxane riskNo (not ethoxylated)Yes (byproduct of ethoxylation)
CostSlightly cheaperSlightly more expensive
Lather qualityThick, denseThick, dense
Common inToothpaste, some shampoosMost shampoos and body washes

The irony is that SLES was developed to be gentler than SLS, and it is gentler on skin. But the ethoxylation process introduces the 1,4-dioxane contamination risk that SLS doesn’t have. Neither option is clearly “better” across the board.

When Going Sulfate-Free Makes Sense

Sulfate-free isn’t necessary for everyone, but it’s a clear improvement in several situations:

You have a dry, flaky, or itchy scalp. Sulfates may be stripping your scalp’s protective oils and exacerbating the problem. Switching to a gentler surfactant often helps.

You have curly, coily, or textured hair. These hair types need their natural oils. Sulfate-free shampoos clean without stripping, which reduces frizz and improves curl definition.

You color your hair. Gentler surfactants preserve color longer between treatments.

You have eczema, rosacea, or contact dermatitis. Reducing skin irritation from any source is helpful, and sulfates are an easy one to eliminate.

You want to reduce your cumulative chemical exposure. If you’re already working to clean up your personal care routine, swapping to sulfate-free products is part of a broader strategy that also eliminates the 1,4-dioxane contamination risk from SLES.

For our recommended sulfate-free shampoos, see our best non-toxic shampoo guide.

What Sulfate-Free Products Use Instead

“Sulfate-free” shampoos and cleansers use alternative surfactants that are generally milder. Common replacements include:

Coco-glucoside and decyl glucoside are sugar-based surfactants derived from coconut oil and glucose. They’re among the gentlest surfactants available. Lather is lighter than sulfates, but cleaning power is adequate for most people.

Cocamidopropyl betaine is derived from coconut oil and is commonly used in “gentle” and “baby” formulations. It’s milder than sulfates but can cause contact dermatitis in a small percentage of people.

Sodium cocoyl isethionate is the surfactant in Dove soap bars and many solid shampoo bars. It’s mild, produces good lather, and is well-tolerated by most skin types.

Sodium lauroyl methyl isethionate is another mild alternative that provides decent lather without the stripping effect of SLS.

Dr. Rhonda Patrick has discussed the broader concept of reducing daily chemical exposures from personal care products, noting that the cumulative burden of multiple products used every day adds up in ways that individual product safety reviews don’t capture. Choosing milder, cleaner-formulated products across the board is a practical strategy.

The Lather Adjustment Period

If you switch from a sulfate shampoo to a sulfate-free one, expect a 2-3 week adjustment period. Sulfate-free shampoos lather less, which doesn’t mean they’re cleaning less effectively. It means you’re not creating the artificial foam that your brain has been trained to associate with “clean.” Your hair may feel different during the transition as your scalp adjusts its oil production. Give it time.

How to Check Products for Sulfates and 1,4-Dioxane

On the Label

Look for these names in the ingredient list:

  • Sodium Lauryl Sulfate (SLS)
  • Sodium Laureth Sulfate (SLES)
  • Ammonium Lauryl Sulfate (ALS)
  • Ammonium Laureth Sulfate (ALES)

Any ingredient with “eth” in its name (laureth, myreth, ceteareth) has been ethoxylated and carries a potential 1,4-dioxane contamination risk.

Beyond the Label

Since 1,4-dioxane is a contaminant, it won’t appear on any ingredient list. Your best tools are:

  • EWG’s Skin Deep database rates products and flags contamination concerns
  • MADE SAFE certification tests for 1,4-dioxane
  • EWG Verified products have been tested to ensure they’re free from contamination

See our non-toxic certifications guide for details on what each certification covers.

Where We Land on Sulfates

Sulfates are not the terrifying chemicals that some marketing would have you believe. They’re effective surfactants with a documented irritation potential and, in the case of SLES, a contamination concern that matters.

Whether to avoid them depends on your individual situation. If you have sensitive skin, dry or textured hair, or you’re working to reduce your overall chemical exposure, sulfate-free products are a worthwhile switch. If you have no skin issues and just want your hair clean, sulfates in a rinse-off product at normal concentrations aren’t going to cause you harm.

The bigger issue in most personal care products isn’t the surfactant. It’s the synthetic fragrance, parabens, and formaldehyde releasers that ride along with it. When shopping for better products, look at the whole ingredient list, not just whether it says “sulfate-free” on the front. For a broader look at chemicals to avoid in personal care, see our toxic chemicals to avoid guide.

Questions We Hear Most

Are sulfates safe in toothpaste?

SLS in toothpaste (typically at 1-2% concentration) is safe for most people, but it does cause mouth irritation in some. Research published in the Journal of Clinical Periodontology found that people who switched from SLS-containing toothpaste to SLS-free toothpaste experienced significantly fewer canker sores. If you get frequent mouth ulcers, try an SLS-free toothpaste for a few months to see if it helps.

Do sulfate-free shampoos clean as well?

They clean well enough for most people and most hair types. If you have very oily hair or use heavy styling products, you may need to shampoo twice or use a sulfate-free clarifying shampoo occasionally. The cleaning mechanism is the same (surfactant action); sulfate-free options just use gentler surfactants that are less aggressive at stripping oils.

Is “derived from coconut” the same as coconut oil?

No. SLS can be derived from coconut oil (the lauric acid starting material comes from coconut), but the final product is a synthetic surfactant that bears no resemblance to coconut oil. The “derived from coconut” language on labels is technically accurate but misleading. It implies a natural product when the end result is a heavily processed chemical.

Can sulfates cause hair loss?

There is no evidence that sulfates cause hair loss. They can cause hair breakage by drying out the hair shaft, which might look like hair loss, but the follicle itself isn’t affected. If you’re experiencing actual hair loss (from the root), sulfates are not the cause. If you’re experiencing breakage and thinning, switching to a gentler shampoo may help by reducing dryness and brittleness.

Should babies use sulfate-free products?

Yes. Baby skin is thinner and more permeable than adult skin, and babies are more susceptible to irritation. Most pediatric dermatologists recommend sulfate-free cleansers for infants and young children. See our best non-toxic baby shampoo guide for gentle, sulfate-free options formulated for babies.

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