Toxic Chemical Load #3: Sodium Laurel Sulfate
I recall a time when my friend asked me “Do you know what sodium laurel sulfate [SLS] is?” while we grocery shopped in Chicago. Naturally I answered “No, I don’t”. “Well, it’s a chemical in shampoo that builds up in your body as formaldehyde; ya know, the stuff they embalm people with” she responded. “That is so gross!” I was stunned.
It was 2008 and I had already begun my “clean eating” journey. Having my friend explain this to me was not a surprise, but startling none the same. I didn’t even question if she was right. I was just determined to AVOID SLS at every turn. Since then, I have been adamant to choose skin and body care that does not have toxic ingredients in them. Though usually a costly and inconvenient endeavor, I believe the health benefits will be worth it for life.
As I’ve grown up, I’ve learned to not take someone’s word as truth and authority. I suppose it’s part of maturing and realizing we can all get it wrong, even on a subject we are deemed an “expert” on. As someone who values truth and integrity above all else, I try to devote more time to making sure what I have adopted as truth is actually TRUE. It’s a journey!
So, does SLS become formaldehyde in our bodies… I don’t think so. BUT I discovered there is no way of knowing how the SLS is preserved before it is added to products. They are not required to put that on the label. And it does appear that most SLS is preserved with formaldehyde. So maybe my friend was right after all?
So, what is Sodium Laurel Sulfate (SLS)?
It is a surfactant that helps oil and water mix. It is used in products to make them sudsy and to clean better. Think liquid dish soap, liquid hand soap, shampoo, and toothpaste. It’s also put in food items like marshmallows.
SLS is known for drying out skin by breaking down the epidermis layer. Regulations state it must be under 1% of a product and should not stay ON the skin for any length of time. For example, washing your hands with a SLS product is less irritating than using a lotion with SLS.
SLS is used in a lot of lab tests because of its surfactant nature. Therefore, we do have a lot of scientific data on it.
SLS does not sound that harmful to our bodies when it is diluted properly and only briefly in contact with the skin. That said, it does dry out our skin, which is our biggest organ and part of our immune system.
The problem with SLS seems to arise by what it is preserved with.
There is no evidence that SLS is carcinogenic or that it causes hair loss. Sometimes “lack of evidence” just means they haven’t researched it enough. Due to the abundant lab tests utilizing SLS it does appear that SLS on its own is not carcinogenic. The jury is still out on hair loss. Again, it’s not just about the SLS, it’s about the unknown, carcinogenic preservatives it’s mixed with. Formaldehyde, for instance, is carcinogenic.
The moral of the story is that it’s our responsibility to be informed consumers. Corporations and manufacturers do not have our best interests in mind. They want to make money. Often, shortcuts are made, and cheap toxic chemicals are used to increase profit.
I recommend reading labels and researching the words you do not understand. You will be very enlightened. Many body care products use naturally derived forms of SLS. They are supposed to be healthier options. I’m not sure if that means they are preserved with something less toxic.
Please dive into the research below to learn more.
“Sodium lauryl sulfate (SLS), or one of its cousins like Ammonium lauryl sulfate (ALS) or Sodium laureth sulfate (SLES), is the main cleaning agent and second-largest ingredient after water in most regular brands of shampoo, shower creams, liquid soap, toothpaste, shaving gel, bubble baths, etc.”
The fact that SLS, or its more common name in science, the reason SDS (sodium dodecyl sulfate) is found in so many studies is the same reason why you find it in a lot of cosmetics, household and industrial cleaners – it is cheap! SLS is a cheap surfactant, commonly used in scientific labs to dissolve other molecules, for analytical studies, for toxicological studies and for any other application that does not require more natural conditions such as preserving the 3D-structure and activity of proteins. That is the downside of this very cheap surfactant, it damages protein structures or, correctly expressed, denatures the proteins, and thereby they lose both shape and function. In fact, one of the most used laboratory analytical methods for proteins is based on the ability of SLS to denature proteins (SDS-PAGE).”
Yes, SLS is most likely comedogenic. It has scored positive in the classical rabbit’s ear assay . In spite of that, it is regrettably often found in acne cosmetics.
Can SLS Cause Hair Loss?
SLS has been found accumulated in hair follicles [4, 5, 18] but so far there is no study that supports that SLS could cause increased hair loss.
Does SLS Cause Dry Hair and Split Ends?
Yes, SLS damages the outer surface of the hair strands, the cuticle, resulting in loss of shine, a rougher surface and split ends [19-21]. Even though all anionic surfactants to some extent damage the hair surface compared to only using water, SLS is harsher than all other surfactants used in skin care products.
“SLS is an anionic surfactant commonly used in consumer household cleaning products. For decades, this chemical has been developing a negative reputation with consumers because of inaccurate interpretations of the scientific literature and confusion between SLS and chemicals with similar names. Here, we review the human and environmental toxicity profiles of SLS and demonstrate that it is safe for use in consumer household cleaning products.
“Sodium lauryl sulfate (SLS), also known as sodium laurilsulfate or sodium dodecyl sulfate, is an anionic surfactant commonly used as an emulsifying cleaning agent in household cleaning products (laundry detergents, spray cleaners, and dishwasher detergents). The concentration of SLS found in consumer products varies by product and manufacturer but typically ranges from 0.01% to 50% in cosmetic products1,2 and 1% to 30% in cleaning products.3,4 SLS can be synthetic or naturally derived. This chemical is synthesized by reacting lauryl alcohol from a petroleum or plant source with sulfur trioxide to produce hydrogen lauryl sulfate, which is then neutralized with sodium carbonate to produce SLS.5”
“Down-the-drain cleaning products release SLS into the environment via household wastewater systems. In the environment, >99% of SLS readily biodegrades into nontoxic components per the OECD 301 standard.7”
“Dermal toxicity studies demonstrate that 24-hour exposure to a 1–2% (w/w) solution of SLS can increase the transepidermal water loss of the stratum corneum – the outer most layer of the skin – and cause mild yet reversible skin inflammation.”
“There is no scientific evidence supporting that SLS is a carcinogen.33,34 SLS is not listed as a carcinogen by the International Agency for Research on Cancer (IARC); U.S. National Toxicology Program; California Proposition 65 list of carcinogens; U.S. Environmental Protection Agency; and the European Union. In 1998, the American Cancer Society (ACS) published an article attempting to correct the public’s misconception of SLS.”
“If you are concerned about the possible effects of SLS accumulation, look for shampoos, toothpastes and other personal care products marked “SLS free.” According to Mother Nature Network, a related product known as sodium coco sulfate, which is also a coconut derivative, may be less irritating than SLS or SLES. Look for shampoos made with essential oils, or wash your hair with baking soda.”
“Some products containing SLS include a brief warning somewhere stating that there’s a chance the product could cause skin irritation, dryness or redness on sensitive skin. If you have sensitive skin, always read ingredient labels carefully, and opt for natural skin care products as much as possible, including those that are homemade or store-bought but labeled hypoallergenic and organic.
If you are going to use products containing SLS, try to avoid heating them and mixing them with very warm water, since this can open up the skin’s pores and lead to worsened reactions. One study found that warmer water caused SLS to lead to more skin irritation.
When it comes to avoiding it in foods, your best bet is to limit consumption of processed foods (such as bottled juices, frozen meals and liquid eggs) and read ingredient labels.”