Let's talk about SLS
Industry experts agree that sodium lauryl sulfate (SLS) is safe and effective, so why are we working so hard to remove it from Lush products?
What is SLS?
Sodium lauryl sulfate (SLS) is a chemical that’s commonly used in soaps, shampoos, shower gels and toothpaste. It works as a surfactant, trapping oil-based dirt so that it can be rinsed away with water. It’s also an effective foaming agent — it turns liquids into foam, creating the rich lather that most of us expect and enjoy when we’re washing our face, hair and body.
Despite being used safely and successfully since the 1930s, SLS has a bad reputation. Although experts agree that it’s safe to use, SLS can be drying. This is more likely to be an issue for those who have dry, processed or afro hair, or suffer from skin conditions like eczema, dermatitis or psoriasis — so we’re committed to offering alternatives.
We’re particularly keen to reduce our use of safe synthetic ingredients like SLS because palm oil is used in their production. Since 2008, we’ve been trying to remove palm oil from our supply chain due to the devastating impact its cultivation has on the environment. To produce palm oil, tropical forests are razed to make way for palm tree plantations, displacing indigenous people, destroying wildlife and disrupting the delicate ecosystem in the process. However, boycotting palm oil is easier said than done.
“Finding a suitable palm-free SLS is challenging not only because there isn’t a large market but, when found, it often doesn’t work or the manufacturer doesn’t follow our non-animal testing policy,” explains Mark Rumbell, Lush’s Ethical Buyer.
We’re still working hard to reduce our palm oil print, as this helps us to preserve natural habitats and protect human rights. Mark explains, “We’re looking for materials that can either replace SLS or be used alongside it to reduce our overall usage and create a better product. The aim is to get rid of palm-based SLS altogether.”
In fact, recent additions to our ranges feature sodium coco sulfate, a great alternative that has been put to work to create a more gentle lather that won’t strip the hair and skin of needed moisture while it cleanses. We’re still working on making the change, but we’re closer than ever before with bath, shower and haircare ranges that include this fabulous foamer.
Should you be stressed about SLS?
In recent years, there has been increased negativity towards products that contain SLS, partly because reports have incorrectly linked it to cancer. Nicola Smith, health information officer at Cancer Research UK, told us: “There’s no evidence to suggest that sodium lauryl sulfate causes cancer. Cosmetics are under tight regulation in Europe and have to be shown to be safe before they can be sold. Unfortunately, there are a lot of unfounded rumours on the internet about cosmetics causing cancer but they simply aren’t backed up by convincing scientific evidence.”
It’s likely that these concerns stem from confusion surrounding the manufacturing process. The SLS that we use is derived from coconut and/or palm kernel oil, both of which are rich sources of lauric acid. This lauric acid is processed into SLS by adding sulphuric acid (from petroleum) followed by neutralisation with sodium carbonate (a natural mineral). Some reports have claimed that this process produces chemical compounds known as ‘nitrosamines’, of which 90% are believed to be carcinogenic. However, it’s chemically impossible for nitrosamines to be found in SLS.
“For years, sodium lauryl sulfate has been developing a negative reputation with consumers due to flawed interpretations of the scientific literature that continue to be perpetuated,” says Cosmetic Chemist Kelly Dobos. “Sodium lauryl sulfate is produced by the sulfation of lauryl alcohol. No chemicals used in the synthesis contain nitrogen so the resulting SLS contains no nitrogen and therefore no possible presence of nitrosamines.”
There are also concerns about the impact that SLS can have on marine life, since all soap and shampoo products are released into the environment via household water waste. According to Kelly, we don’t need to worry. She explains: “The ability of a chemical to decompose into simple, nontoxic components under normal environmental conditions within a short period of time (96 hours or less) means that it is biodegradable. SLS has been shown to be readily biodegradable not biopersistent. By the time personal care product ingredients reach natural waters, they are mostly degraded. Ecotoxicity studies have determined that these low concentrations of SLS would be essentially nontoxic to fish and other aquatic life.”
Getting in a lather
Many of us don’t feel completely clean unless we lather up with soaps and shampoos. However, the sulfates which are responsible for producing this luxurious foam can be harsh and drying, leaving hair frizzy. Although dryness is a common concern, irritation is unlikely, even among people who have sensitive skin, provided that the foam is rinsed off thoroughly. In fact, the risk is so small that there are no EU limits on the usage of SLS in wash-off products, as irritation only occurs with products that are left on the skin.
“Most people can use products containing SLS without worrying about skin or scalp irritation,” says Dr Stefanie Morris, Dermatologist & Medical Director at European Dermatology London. “This is because it’s a rinse-off product — the contact time is short and, after rinse-off, there is extremely little SLS (if any), which stays on the skin/scalp.”
Alternatively, shampoo bars are an excellent option for sensitive scalps, mainly because of the way they are used. A single shampoo bar is the equivalent to three 200ml bottles of liquid shampoo, so although they contain a very high concentration of SLS — up to 90% — the risk of irritation is very low because only the foam is applied to the hair and scalp. We recommend shampoo bars to customers who want to reduce their SLS usage because the amount that you apply is easier to control. There’s no need to squeeze a large dollop of shampoo onto your scalp. Instead, you prepare the product in your hands first, before distributing it evenly through the hair.
“This is quite a dramatic difference,” explains Lush co-founder and herbal trichologist Mark Constantine. “When you use a liquid shampoo you apply the neat material to your scalp, but you don’t get that with a shampoo bar — you only get the foam that comes off the material, which means that even people with the most sensitive scalps can use it.”
Raising the bar
The foaming and cleansing base of all our soaps has been palm-free since 2006. We purchase it from an external soap manufacturer that uses rapeseed and coconut oil. Despite the many fresh, soothing ingredients we add, this base can be a bit drying, giving that slightly rough feel to the skin after rinsing off. That's why we’ve been adding SLS to the formula - to make the foam generous, but above all to get a really soft feeling.
In 2017, we reformulated our soap range to make it entirely palm free and therefore sulfate-free. After long hours of research and development, we have succeeded in creating our own soap bases, made in-house. This allows us to use the vegetable oils and butter we want and to experiment with textures, lathers and effects on the skin. Used on their own or alongside our classic soap base, they provide a next-level softness that replaces the need for SLS (and sodium stearate, another palm-derived ingredient).
The majority of our soaps no longer contain SLS. What this all means is that you now have even more choice, making it easier to find the products and ingredients that work best for you. What's coming next? Watch this space.