What Are Sulfates & Why Are They Harmful?

Sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) are two commonly used ingredients found in many soaps and shampoos. However, you might have noticed that quite a few influencers are cautioning against their use.

Both of these compounds act as surfactants, which help create that lovely lather we often associate with cleanliness. While lathering can feel nice, the downside is that SLS and SLES can be harsh on the skin and hair, potentially stripping away natural oils and leading to dryness or irritation.

Many people are opting for gentler alternatives, particularly if they have sensitive skin or conditions such as eczema. When shopping for personal care products, look for sulfate-free options that use milder cleansers. It’s always a good idea to read labels and choose products that nourish rather than strip away your skin’s natural moisture.

In this article, we will learn everything there is to know about sulfates & why you must be careful if your personal care product contains sulfates.

• What Are Sulfates?
  – Different types of sulfates
• Is Sulfate Dangerous?
  – Side Effects of Sulfate on hair & body
• Does Sulfate Cause Cancer?
• What Does Science Say About Sulfates?

What Are Sulfates?

Sulfate is a naturally occurring compound formed when sulfur combines with oxygen. It is found in the soil, air, and water and plays a significant role in various cellular processes within the body.

There is also a synthetic version of sulfate, which is commonly present in many household and personal care products. Different industries utilize sulfate in the production of their goods, including food and drink. Additionally, some sectors combust fuels that contain sulfur, resulting in sulfate formation in the atmosphere. While these sulfates can contribute to acid rain in polluted air, they also reflect light, which can aid in cooling the climate.

Where Is Sulfate Found?

Sulfate, a salt or ester of sulfuric acid, is widely found in various forms naturally occurring in the environment, but it is also synthesized for use in a variety of consumer products. One of the most common synthetic forms of sulfate is sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES), which are both produced by combining sulfate with other chemicals.

These compounds are primarily utilized as surfactants due to their ability to lower the surface tension of water, making it easier for water to mix with oils and dirt. As a result, SLS and SLES have a wide range of applications, particularly in cleaning and personal care products. Some of the most notable uses include:

• Shampoos and Conditioners: Sulfates are often used as cleansing agents in shampoo and conditioner formulations because they create a rich lather, helping to remove dirt, oil, and product buildup from hair.
• Toothpaste: In toothpaste, sulfates provide foaming action, which can help with the distribution of the product in the mouth and enhance the cleaning of teeth.
• Mouthwash: Similar to toothpaste, sulfates in mouthwash can contribute to a refreshing feel and assist in the even spread of ingredients for better oral hygiene.
• Bodywashes: Many body washes contain sulfates to create suds that aid in the removal of impurities from the skin while providing a pleasant cleansing experience.
• Laundry Detergents: Sulfates are included in laundry detergents to boost cleaning efficiency, helping to lift stains and dirt from fabrics during the washing cycle.
• Dish Detergents: In dishwashing liquids, sulfates help to disperse grease and food residues, providing streak-free dishes while also generating foam.
• Hand Soap: Hand soaps frequently contain sulfates for their cleaning properties, allowing for effective removal of germs and dirt from hands.

Personal care products frequently use sulfates, Sodium Lauryl Sulfate (SLS) and Sodium Laureth Sulfate (SLES), serve the purpose of creating lather and helping to cleanse the skin and hair by breaking down oils and dirt. However, while they are effective surfactants, they can also have some negative impacts on hair health. When sulfates are used in detergents, they can effectively strip away natural oils from the hair and scalp. These oils play a crucial role in maintaining hair moisture and keeping it healthy. As a result, regular use of products containing sulfates, especially if they are particularly harsh or if the product is used excessively, may lead to hair that is dry, brittle, or damaged. This is particularly concerning for individuals with naturally dry or textured hair, as they may already struggle to maintain adequate moisture levels. It’s important to note, however, that sulfates do not directly cause hair loss. The relationship between hair loss and the use of sulfate-containing products is a misconception. While sulfates may contribute to dryness or damage, which can affect the overall appearance and health of the hair, they do not disrupt the hair growth cycle or lead to conditions that cause hair follicles to stall or hair strands to fall out.

Given their widespread use, sulfates have become a common point of discussion regarding skin sensitivity and potential irritant effects, leading many brands to explore sulfate-free alternatives.

Additives in some foods serve various purposes, from enhancing flavor and texture to improving shelf life and nutritional value. Sulfate in food, here are some common examples:

• Liquid Egg Whites: Often used in baking and cooking for their high protein content without the fat of yolks, liquid egg whites may contain preservatives to maintain freshness and prevent spoilage. They are popular in health-conscious recipes and often found in products designed for athletes seeking protein-rich meals.
• Marshmallows: A sweet treat commonly used in desserts, marshmallows contain gelatin, which acts as a stabilizer and thickener. They may also include various additives such as corn syrup, which helps prevent crystallization, and artificial flavorings or colorings to enhance their appeal.
• Beverage Concentrates: These are highly flavored liquids designed to be mixed with water to create drinks. They often contain preservatives, sweeteners, and colors to enhance taste and appearance. Beverage concentrates allow for convenient storage and extended shelf life while providing intense flavor in smaller volumes.
• Cooking Oils and Fats: Various additives may be included in cooking oils and fats to improve stability and flavor. For example, antioxidants can be added to prevent rancidity, while artificial flavors and emulsifiers might be used to create consistent texture and taste across different batches of oil products.

Each of these food additives plays a crucial role in enhancing the overall quality and safety of the foods we consume.

Types of Sulfates

Type of Sulfate	Is It Dangerous?	Why Are They Considered Dangerous?
Sodium Lauryl Sulfate (SLS)	Potentially irritating	It is a strong detergent that can strip natural oils, causing dryness, skin irritation, and scalp sensitivity. Can worsen eczema or dermatitis in sensitive individuals.
Sodium Laureth Sulfate (SLES)	Mild risk	It is a strong detergent that can strip natural oils, causing dryness, skin irritation, and scalp sensitivity. It can worsen eczema or dermatitis in sensitive individuals.
Ammonium Lauryl Sulfate (ALS)	Moderate risk for sensitive skin	Strong cleansing agent that can cause irritation or dryness, similar to SLS, though usually milder.
Ammonium Laureth Sulfate (ALES)	Low to moderate risk	Less harsh than SLS, but can contain 1,4-dioxane, a possible carcinogen formed during manufacturing (ethylene oxide contamination). Also may irritate the skin for sensitive users.
TEA (Triethanolamine) Lauryl Sulfate	Potential risk	Similar to SLES, concerns around possible contamination with 1,4-dioxane and potential irritation for sensitive skin.
Sodium Myreth Sulfate (SMS)	Lower risk	Gentler than SLS/SLES, but still has potential contamination concerns and may irritate very sensitive skin.
Sodium Coco-Sulfate (SCS)	Moderate risk	Can irritate; may form nitrosamines (possible carcinogens) when interacting with certain preservatives.
Sodium Cetyl Sulfate	Low risk	Less harsh than SLS; still may irritate sensitive skin due to its detergent properties.
Sodium Stearyl Sulfate	Low risk	Marketed as “natural,” but still a mixture of harsh sulfates similar to SLS. It can irritate skin despite being derived from coconut.

How To Avoid Sulfate?

Sulfates are a diverse group of mineral salts, commonly found in various personal care and cleaning products due to their effective cleaning and foaming properties.

Examples include shampoos, conditioners, body washes, and even toothpaste. Despite their widespread use, sulfates can cause skin and eye irritation in some individuals, particularly those with sensitive skin or conditions like eczema.

To minimize your exposure to sulfates, consider the following tips:

• Use sulfate-free products: Many brands now offer sulfate-free options, especially in hair and skincare lines. Look for products labeled as “sulfate-free” to avoid sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES).
• Filter your drinking water: If you’re concerned about sulfates in your drinking water, investing in a quality water filtration system can help. Reverse osmosis filters are particularly effective at removing a wide range of contaminants, including sulfates.
• Read labels carefully: Educate yourself on the ingredients to look out for. In addition to SLS and SLES, you may also find sodium dodecyl sulfate and other sulfate derivatives. Familiarizing yourself with these terms can empower you to make informed choices when shopping.

If you have a known sensitivity or allergy to sulfates, it’s important to consult with a healthcare professional. Speaking to your doctor can provide insights into your sensitivities, and they may refer you to a dermatologist or allergist for further evaluation. A dermatologist can conduct tests to identify triggers for skin irritation and recommend suitable alternatives or treatments to help alleviate symptoms.

Furthermore, using gentle, fragrance-free moisturizers and cleansers may also assist in soothing sensitive skin while avoiding potential irritants commonly found in sulfate-containing products. Always perform a patch test when trying new products to ensure they’re compatible with your skin type.

What Does Science Say About Sulfates?

Sulfates, particularly sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES), are prevalent surfactants commonly found in a variety of personal care items such as shampoos, cleansers, body washes, and toothpastes.

Their primary function is to effectively bind to oils and impurities, facilitating their removal during rinsing. Despite their efficacy as cleansing agents, emerging scientific research underscores the importance of understanding their implications for skin health, including potential irritation and safety issues.

Skin Irritation & Barrier Disruption: Extensive research has established that SLS is a potent skin irritant. A multitude of controlled studies have utilized SLS to serve as a benchmark irritant, intentionally disrupting the skin barrier due to its consistent ability to increase transepidermal water loss (TEWL).

The consequences of SLS exposure can manifest as:

• Increased transepidermal water loss, leading to dehydration of the skin.
• Redness, dryness, and even inflammation of the skin’s outer layer.
• Weakening of the lipid barrier, which is crucial for maintaining skin moisture.
• Alteration of cell structure, particularly affecting keratinocytes, which may interfere with normal skin function.

The degree of irritation from SLS appears to be dose-dependent; that is, it typically escalates with prolonged exposure, higher frequency of use, and individual predispositions, such as pre-existing conditions like eczema or compromised skin integrity.

Additionally, there is evidence suggesting that SLS can disrupt the skin’s microbiome, resulting in a decrease in beneficial bacteria and fostering an environment for opportunistic microbes to thrive in specific patch-test scenarios.

SLES: Milder, but With Contamination Concerns

Sodium laureth sulfate (SLES), on the other hand, is regarded as a gentler alternative to SLS, primarily due to its undergoing a process known as ethoxylation. This modification renders it less abrasive. Nonetheless, the ethoxylation process is not without its drawbacks, as it can leave behind residues of 1,4-dioxane, a compound recognized for its potential carcinogenic properties.

In contemporary manufacturing processes, significant strides have been made to minimize the presence of this contaminant. Many manufacturers have adopted purification techniques, such as “vacuum stripping,” to eliminate 1,4-dioxane, adhering to increased regulatory scrutiny at the global level.

Safety Assessments From Regulatory Bodies

Regulatory bodies, including esteemed independent panels like the Cosmetic Ingredient Review (CIR), have carefully assessed sulfates. Their evaluations generally conclude that sulfates are considered safe for use in rinse-off formulations at standard concentrations. However, it is worth noting that the likelihood of irritation may increase with higher concentrations of sulfates or when these ingredients are utilized in leave-on applications.

Formulators are advised to factor in exposure duration, dilution ratios, and the inclusion of buffering agents to mitigate irritation risks. Consequently, most health organizations maintain that sulfates are permissible provided they are utilized judiciously.

This question often arises due to the presence of sodium lauryl sulfate (SLS) in numerous consumer products, particularly in cleaning supplies and cosmetics. However, extensive research has shown that SLS is not a carcinogen. According to established organizations such as the International Agency for Research on Cancer, the U.S. Environmental Protection Agency (EPA), and the U.S. National Toxicology Program, SLS has not been included in any lists of substances known to cause cancer. Similarly, California Proposition 65 and the National Library of Medicine’s TOXNET® database do not recognize SLS as a carcinogenic agent. Furthermore, SLS does not accumulate in the human body. While it can be absorbed through the skin, any minimal quantity that enters the bloodstream is metabolized efficiently. The body eliminates SLS through urine, feces, or exhalation, which minimizes any potential risk associated with its use. This indicates that SLS does not pose a risk of inducing cancer or other health issues related to prolonged exposure. Thus, consumers can feel more at ease when using products containing sodium lauryl sulfate.

Environmental Considerations

From an ecological standpoint, sulfate surfactants exhibit a degree of toxicity to aquatic life at certain concentration thresholds, although many of them are biodegradable. The environmental implications hinge significantly on the quality of wastewater treatment processes and adherence to regional environmental standards, which can vary widely.

Who Should Avoid Sulfates?

Scientific evidence advocates for caution or outright avoidance of sulfates in specific populations, including:

• Individuals suffering from skin conditions such as eczema, psoriasis, dermatitis, rosacea, or those with inherently dry or sensitive skin.
• Anyone who experiences adverse reactions, such as scalp or skin irritation, from standard shampoos or cleansers that contain sulfates.
• Those who have concerns regarding potential contamination from 1,4-dioxane may also wish to investigate alternatives.

For those seeking gentler cleansing solutions, alternatives such as coco-glucoside, decyl glucoside, and sodium cocoyl isethionate may offer better skin compatibility.

Scientific evidence advocates for caution or outright avoidance of sulfates in specific populations, including individuals with sensitive skin, those suffering from skin conditions such as eczema or psoriasis, infants and young children, and individuals with allergies or sensitivities to certain chemicals. These populations may experience adverse reactions to sulfates, such as skin irritation, dryness, and exacerbation of existing skin issues.

Additionally, sulfate-containing products can disrupt the natural barrier of the skin, leading to increased moisture loss and further sensitivity. As a result, it is important for these individuals to carefully read product labels and consider sulfate-free alternatives to maintain healthy skin and prevent negative reactions.

While sulfates are recognized for their effectiveness as surfactants, there are associated risks, particularly regarding skin irritation. They are known to:

• Deliver superior cleaning capabilities.
• Be safe for use in rinse-off products within designated concentration limits.
• It possesses the potential to irritate or compromise the skin barrier, especially with consistent application or on sensitive skin types.
• Possibly contains trace contaminants depending on the manufacturing processes employed.

Choosing sulfate-free products is not typically a medically essential decision for most individuals; however, they can offer meaningful benefits for those with sensitive or delicate skin who wish to reduce irritation and support skin health.

Scientific Studies On The Risk of Sulfates

Study & Findings
Cutaneous sodium lauryl sulphate irritation potential: age and regional variability — SLS (0.25%) caused significant erythema and increased transepidermal water loss (TEWL) in human skin; older subjects showed less sensitivity than younger in many regions. (PubMed)
Long-term repetitive sodium lauryl sulfate–induced irritation of the skin: an in vivo study — Repeated exposure (over 103 days) led to persistent erythema, elevated TEWL, and signs of skin barrier disruption; skin “accommodation” did not fully prevent irritation. (PubMed)
Irritating effects of sodium lauryl sulfate on human primary keratinocytes at subtoxic levels of exposure — In vitro, keratinocytes exposed to very low SLS (≥ 25 µM) showed inflammatory responses and biomechanical changes (reduced stiffness), indicating even low doses can be harmful.
Effect of sodium lauryl sulfate–induced skin irritation on in vitro percutaneous absorption of four drugs — Pretreatment of skin with SLS (0.5%) increased the percutaneous penetration of drugs (hydrocortisone, ibuprofen, indomethacin) in guinea pig skin, likely due to barrier damage.

Sulfates are naturally occurring substances that can be found in your body and in various foods, cleaning products, and even the air. Research has not indicated that sulfates are harmful to health or linked to cancer.

Individuals with sensitive skin might occasionally encounter irritation, dryness, or itchiness upon exposure. Consuming large amounts of certain foods or water may result in diarrhea. To minimize sulfates in your surroundings, you may wish to consider avoiding products with SLS or SLES and using a water filter for drinking water.