A Daily Dose of Sodium Lauryl Sulfate

Figure 1. Some of the everyday products we use that contain SLS [6].

Every day, I use mouthwash, toothpaste, shampoo, and conditioner. These personal care products all have something in common- the controversial ingredient, sodium lauryl sulfate. Rumors have been circulating the internet and by word of mouth that this is a huge factor for cancer, hair loss, skin and eye irritation, and many other health issues [1]. Considering that we get in contact with this ingredient at least once a day from the products that we use, will it be a cause for concern if this accumulates in our bodies? 

Here's what we need to know about Sodium Lauryl Sulfate (Chemical formula: C12H25NaO4S), otherwise known as sodium dodecyl sulfate, irium, or for shorter terms of the name itself, SLS. This is not to be confused with sodium laureth sulfate (SLES), another ingredient in shampoos, although they have more or less similar properties. If you ever wonder why your shampoo or toothpaste starts off as a simple paste or gel and starts to bubble when you add a little amount of water into it and it gets in contact with your teeth or hair, that's the SLS doing its magic as a surfactant. Surfactants exposed to liquid have reduced surface tension that causes its wetting and spreading properties to be more maximized [3]. SLS by itself can appear creamy, pale yellow, or white, and come in forms of powder, crystals, or flakes [2]. 

SLS is usually taken from plants and then synthesized in labs. [2] This is infused in most of our personal care products, and if you ever think about avoiding this ingredient, you can find alternatives such as alkanolamides, and betaine which can be beneficial if you are particular with oral health care as it has a lesser chance of causing mucosal irritation, but its effect as a surfactant won't be as great as SLS itself [4]. It also came as a surprise to me that this is also found in some kinds of food such as dried egg products and marshmallows. Now, does it concern you that this has been something we have been shoving down our throats and into our bodies?

Cancer is on top of the list as a controversy for SLS because it is suspected to have a chemical reaction with formaldehyde to produce nitrosamines, a carcinogenic by-product. This was disproven because it is impossible since neither contain nitrogen atoms while nitrosamines are known to have two of those. SLS is not in the list of cancerous chemicals either. Phew! Moving on, skin irritation and mild allergies are two known side effect of using SLS constantly [5]. This is partially true for dermal irritation since it will entirely depend on how long you have been exposed to an SLS-containing product, but this is not a cause for concern since it will take a huge amount of SLS for your skin to be affected. Besides, there are many other ingredients in products that we have to consider that may be causing skin irritation. SLS as an allergen on the other hand has no scientific evidence to prove it [1]. 

Now that we have cleared out SLS of some of the accusations thrown against it, it may be safe to say that we can use products with SLS without fear of having this chemical accumulating in our bodies over time and eventually kill us. Some chemicals sound harmful and could be a cause of concern if it is something we are exposed to everyday, but with a little more research and reading, we could be surprised at what more these chemicals can do.



REFERENCES
[1] Bondi, C., Marks, J., Wroblewski, L., Raatikainen, H., Lenox, S., and Gebhradt, K. (2015). Human and environmental toxicity of sodium lauryl sulfate (SLS): evidence of safe use in household cleaning products. Retrieved from  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651417/#b15-ehi-9-2015-027.

[2] Sodium lauryl sulfate (n.d.). Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/3423265.

[3] Surfactant (2020). In Britannica Encyclopaedia. Retrieved from https://www.britannica.com/science/surfactant.

[4] Rantanen, I.,  Nicander, I.,  Jutila, K., Ollmar, S., Tenovuo, J., Söderling, E. (2006). Betaine reduces the irritating effect of sodium lauryl sulfate on human oral mucosa in vivo. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/12418722.

[5] Ash, M. (2004). Handbook of Preservatives. Retrieved from https://books.google.ca/books?id=XZ2QB7bu5LwC&pg=PA535&dq=sodium+lauryl+sulfate&hl=en&sa=X&ved=0ahUKEwiyxqrAkcnnAhVHrp4KHcr3DxcQ6AEIPzAD#v=onepage&q=sodium%20lauryl%20sulfate&f=false

[6] Mabugat, N. (2020). Daily Personal Care Products (photograph). Alberta, Canada.