Gentle toothpaste foam

What is Sodium Lauryl Sulfate (SLS) and why is it in toothpaste?


Sodium lauryl sulfate, or SLS, is an ingredient that can be found in some toothpastes, shower gels, shampoos, and household cleaning products. But what is SLS, exactly, and why would some people want to choose a toothpaste without sodium lauryl sulfate? Read on to find out more.

What is Sodium Lauryl Sulfate (SLS)?

Sodium lauryl sulfate is an anionic surfactant that is used for cleaning. It is the most commonly used detergent in the beauty industry, and essentially helps liquid substances “foam”. Originally developed in 1930 for the laundry industry to clean clothes, it became popular in many products, specifically within the Beauty & Personal Care aisles1. SLS helps to remove dirt and oils which is why it is used in many cleaning products.

What is SLS in toothpaste?

SLS is often used as a toothpaste foaming agent, helping the cleaning system in removing stains  plaque and food deposits. Many foaming toothpastes will therefore contain SLS. However, SLS can irritate sensitive gums and cheeks in some people, and so choosing an SLS-free toothpaste may be beneficial for those with more vulnerable mouths.

Can SLS cause mouth ulcers?

Most people don’t experience any side effects from having SLS in toothpaste; however, SLS may cause skin irritation, including inside the mouth. As Dentist Surina Sehgal states, this is particularly a problem for people who suffer from mouth ulcers, and SLS can increase the frequency of repeated mouth ulcers1:

Those who suffer with a dry mouth may also benefit from SLS free toothpaste and it can also be too harsh for pregnant women and even young children whose mouths are more sensitive.
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Dentist Surina Sehgal

Who might benefit from choosing a toothpaste without sodium lauryl sulfate?

Woman touching her cheek

As we have seen, SLS can be a cause of mouth irritation and so if you have mouth ulcers, a toothpaste without sodium lauryl sulfate may be beneficial for you. Other people who may benefit from using an SLS-free toothpaste include:

  • People who have sensitive mouths: If your mouth is sensitive, toothpaste without SLS may be a good option for you as sensitive mouths may be more susceptible to irritation.  
  • Lichen planus sufferers: Lichen planus is a rash that affects various parts of the body, including the mouth2. If you suffer from this, it’s best to avoid a toothpaste that may further irritate the inside of your mouth. As the inside of your mouth will be sensitive, toothpaste without SLS may be a good option. 
  • Those who suffer from dry mouth: SLS can causes dryness inside the mouth and so people who suffer from a dry mouth might try a low-foaming toothpaste without sodium lauryl sulfate to avoid aggravating the issue. 
  • Those with aphthous ulcers: Patients with a delicate oral mucosa are more likely to find SLS containing toothpastes less suitable, especially those with aphthous ulcers as Sodium lauryl Sulfate toothpaste can increase the frequency of repeated mouth ulcers1
  • Those whose mouths are more sensitive: Those with more sensitive mouths, such as pregnant women and children may also benefit from using an SLS-free toothpaste, as their mouths tend to be more delicate1.

What is SLS-free toothpaste and how do you choose one?

Zendium toothpaste floating in water

If you are someone who would benefit from using an SLS-free toothpaste, then the next step in your oral care journey is to choose a toothpaste that is suitable for your mouth. But how do you know what toothpaste does not contain sodium lauryl sulfate and how do you go about choosing one?  

  • Check the ingredients: A simple way to check whether a toothpaste is SLS free is to check the ingredients list.  
  • Foaming quality: As SLS is a toothpaste foaming agent, a low-foaming toothpaste is likely not to contain SLS. 
  • Choose a trusted brand: If you want to find a toothpaste that won’t irritate your mouth, it’s good to choose a trusted brand designed for use even by those who have sensitive or vulnerable mouths, such as those who are pregnant or who suffer from mouth ulcers. Zendium provides toothpaste without SLS that is gentle on your mouth while still providing an effective clean. Zendium uses a gentle foaming agent instead of SLS, meaning that it is it is 4x kinder to vulnerable mouths than a toothpaste containing SLS and is less likely to irritate the mouth’s delicate tissues or distort taste of food and drinks like other toothpastes with SLS do3
  • Ask your dentist: The easiest way to find the right toothpaste for your specific oral care needs will be to speak to your dentist. They will know your dental history and be able to make recommendations to help keep your teeth healthy. 

Educating yourself on the different ingredients of products such as toothpaste is a great way to gain a deeper understanding into your oral health. If you are unsure about whether a toothpaste is right for you, speak to your dentist about your options. 


1 Could SLS toothpastes be Irritating Some Patient’s Mouths?

2 Herlofson BB. Barkvoll P. Sodium lauryl sulfate and recurrent aphthous ulcers. A preliminary study. Acta Odontol Scand 1994: 52: 257-259

3 NHS – Lichen Planus

4 Zendium Ingredients

The advice in this article does not constitute medical advice; it is solely available for information purposes. We recommend that you consult your dentist if you are experiencing any tooth or gum problems.