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​Can SLS and  Surfactants Damage Hair and Scalp​?

​Can SLS and Surfactants Damage Hair and Scalp​?

Posted by Nataly Komova on May 22, 2023

damaged hair

The health and appearance of our hair and scalp play a significant role in our confidence and self-esteem. Thus, it is essential to understand the potential effects of different hair care products on our hair and scalp health. One common concern among consumers is the use of SLS (sodium lauryl sulfate) and surfactants in hair care products. SLS and surfactants are widely used in shampoos and other hair care products due to their ability to create lather and remove dirt and oil. However, there has been ongoing debate on their potential damaging effects on hair and scalp. In this article, we will delve into the topic and explore whether SLS and surfactants can indeed cause harm. 

Understanding SLS and Surfactants 

Sodium lauryl sulfate (SLS) is a surfactant used in various personal care products, including liquid shampoos, soaps, toothpaste, and even many shampoo bars brands. Surfactants are responsible for reducing the surface tension between liquids and solids, enabling them to interact more. In the context of shampoos, SLS and other surfactants help create a foamy lather that aids in the removal of dirt, oil, and styling products from the hair and scalp. 

The Potential Effects on Hair 

One of the primary concerns on the use of SLS and surfactants in hair care products is their potential effects on the hair. It is argued that these ingredients can cause damage and negatively impact the overall health and appearance of the hair. SLS and surfactants are powerful cleansers that can remove dirt, oil, and product buildup from the hair and scalp. However, in the process, they can also strip away the natural oils produced by the scalp. This natural oil, known as sebum, helps to keep the hair moisturized and protected. When the oils are excessively removed, the hair can become dry, brittle, and prone to breakage.  

Another potential effect of SLS and surfactants on the hair is increased porosity. Porosity refers to the hair's ability to absorb and retain moisture. When the hair cuticles are lifted or damaged, it can lead to increased porosity. SLS and surfactants have been associated with causing damage to the hair cuticles, making the hair more porous. This can result in the hair absorbing moisture quickly but also losing it just as rapidly, leading to dryness and frizz. The lack of moisture and sebum can lead to a rough texture, making the hair more difficult to manage and style.

For individuals who color their hair, SLS and surfactants can also have an impact on the longevity and vibrancy of the color. These ingredients can cause the color molecules to leach out from the hair shaft, causing premature fading. This is especially true for semi- permanent or direct dye colors that are not deeply infused into the hair cuticle. 

The aggressive cleansing action of SLS and surfactants can potentially weaken the hair structure over time. Constant exposure to these ingredients, particularly in high concentrations, can lead to the degradation of proteins in the hair, resulting in weaker strands that are more prone to breakage and split ends. It is important to note that the potential effects of SLS and surfactants on the hair can vary depending on various factors. These factors include the concentration of these ingredients in the product, the frequency of use, individual hair type, and the hair care routine. Many hair care products containing SLS and surfactants also include conditioning agents and moisturizers to mitigate potential damage and maintain the hair's health and moisture balance. 

Impact on the Scalp 

Another area of concern is the impact of SLS and surfactants on the scalp. Some individuals may experience scalp irritation, itching, or redness due to the aggressive cleansing action of these ingredients. This is especially true for individuals with sensitive skin or pre-existing conditions such as eczema or dermatitis. In such cases, it is advisable to opt for SLS-free or mild surfactant-based shampoos specifically designed for sensitive scalps. 

Are there Side Effects of SLS? 

The use of sodium lauryl sulfate (SLS) in hair care products has been associated with several potential side effects. While not everyone may experience these side effects, individuals with sensitive skin or certain hair types may be more prone to adverse reactions. SLS is a powerful surfactant that effectively removes dirt, oil, and product buildup from the hair and scalp. However, its strong cleansing action can also strip away the natural oils produced by the scalp. This can result in dryness, as the hair is deprived of its natural moisture and protective barrier. Without this barrier SLS has the potential to cause scalp irritation, particularly in individuals with sensitive skin or those who are prone to conditions such as eczema or dermatitis. This can manifest as itching, redness, and inflammation on the scalp. Some individuals may develop allergic reactions to SLS, resulting in symptoms such as itching, rash, hives, or even contact dermatitis. Allergic reactions can vary in severity, and it is important to discontinue the use of products containing SLS if such reactions occur. 

Finding the Right Balance

While there are potential concerns associated with the use of SLS and surfactants in hair care products, it is important to recognize that not all individuals will experience adverse effects. Many people use shampoos containing these ingredients without any issues. Moreover, advancements in cosmetic science have led to the development of milder surfactants and alternative cleansing agents that aim to minimize potential damage. Aquarian Bath offers excellent SLS-free and surfactant-free shampoo bars and soap options.


The use of SLS and surfactants in hair care products can have varying effects on hair and scalp health. While some individuals may experience dryness, brittleness, and scalp irritation, others may not be adversely affected. It is crucial to consider individual hair type, scalp sensitivity, and the formulation of the product when choosing hair care products. Additionally, exploring alternatives such as sulfate-free or mild surfactant- based shampoos, such as Aquarian Bath shampoo bars, can be beneficial for those who are concerned about the potential damage caused by SLS and surfactants. 

3 shampoo set and soap sample

Nataly Komova, fitness and nutritionist expert 

Human Nutrition & Health, BSc Hons