There are a lot of misconceptions out there when it comes to surfactants. This post will dig into the common myths, and their realities, as well as why it’s in formulators’ best interests to correct these misconceptions when we have the opportunity. I think a lot of people don’t know what surfactants are to begin with, so that’s where we’ll start!
What are surfactants?
(Surface Active Agents) Surfactants are chemicals that reduce the surface tension between different liquids. They are amphiphilic with a fat-loving and water-loving part which enables their behaviour – e.g. in detergency or in holding oil and water emulsions together. In cosmetic products, surfactants are the hero ingredients that allow the different product formats we’ve come to love, from shampoos to conditioners to lotions and more!
A common general misconception about surfactants in beauty is that they’re only in cleansing products. Emulsifiers are also a type of surfactant! Their chemistry is just different – these guys are better suited to being left on your skin and for contributing to moisturization.
Did you know? The primary driver of why people like leave-on moisturizing products is largely driven by the emulsifier system! This contributes to the vast majority of the sensory appeal when you’re first trying e.g. a lotion. As a formulator, one of the most significant ways you can change how a product feels is by changing up the emulsifiers.
Surfactants are chemicals widely used for other sectors, from asphalt (in their emulsions), in agriculture (e.g. to get pesticides to work effectively), in transportation (e.g. in some of the needed solvents), and more! They are arguably some of the most important chemicals for society to function as we currently expect.
With that background info, here are some common surfactant misconceptions I’ve seen in beauty that are ultimately probably leading to worse final products. Or at least finished products that are unnecessarily more difficult to formulate, at a significantly higher cost.
Sodium Lauryl Sulfate (SLS) is actually fine!
SLS-free was one of the industry’s first free-from claims. As a result, compared to other surfactants, SLS has hands down the most misconceptions around it and deserves a whole myth busting section here. Here are the top 3 misconceptions I see about SLS in the beauty industry.
- SLS-FREE DOES NOT MEAN MORE GENTLE!
This misconception stems from basic misunderstandings about how formulations work.
In case you don’t already know, SLS is a type of cleansing surfactant. SLS, compared to other surfactants, is very good at cleansing, which is very beneficial to serve a broad range of different end products. In the context of cosmetics, you can use less, compared to other cleansing surfactants, to reach the performance you’re after.
Since it is such an effective cleanser, if SLS is applied to your skin at a high concentration and left there, it would be harsh and irritating. This is the basis of the hazard data that the fearful messaging around harshness stems from. But this is not how SLS is used. In beauty, it’s added at low %s to drive the performance we’re after. Considering full formulas and how they’re used, you can produce very gentle cleansing products with SLS that are suitable for even the most sensitive skin. On the flip side, with alternative surfactants – these generally have to be added at higher concentrations to reach the performance consumers are happy with. While these surfactants on their own may be less harsh, with higher %s, it’s not difficult to create products that are harsh. Potentially even more harsh than formulas with SLS.
Ultimately, how ingredients perform hinges on the formulations they’re put in, and how it all comes together.
- SLS DOES NOT MEAN THE SHAMPOO WILL FADE COLOR FASTER!
There’s been quite a few studies at this point showing that all surfactants impact color fading comparably. When shampoos, with any kind of surfactant, are compared to a placebo water treatment, water can produce the same degree of color fading. Meaning? It’s not the shampoo that’s the major culprit behind your color fading. It’s the water.
Interestingly, a few years ago Good Housekeeping Institute Beauty Labs tested several shampoo products on the market, w/ and w/o SLS, to see which performed best for preventing color fade. Many of the top performing products? They contained SLS.
- SLS-FREE DOES NOT MEAN BETTER FOR THE ENVIRONMENT!
This one is really annoying to me because it is just so obtuse if you know a little about how surfactants are made at industrial scales.
First, SLS is readily biodegradable, so there’s that. In terms of how SLS is made, due to market preferences and the scale of production, SLS is produced via a continuous production method. In contrast, other surfactants, due to their lower scales of production, tend to be made in batches. Here, each start and stop of manufacturing drives up the total environmental footprint. If we were to actually measure it, SLS would likely come out on top from an environmental POV (would be great to see someone do this!).
There’s also the fact that SLS formulas can be thickened via salt whereas other surfactants may require additional gelling agents (such as gums). Compared with salts, these gelling agents have substantially larger impacts (we’re also very good at producing salt), and are substantially more expensive.
Why are SLS-free cleansers more expensive? You need more expensive surfactants at higher %s + more expensive gelling agents. These products aren’t “better”, they’re just less efficient.
Common General Surfactant Misunderstands
With SLS misconceptions out of the way, there are a lot of other misconceptions related to surfactants, including in the technical cosmetics science spaces. Walk any trade show floor and you will see these misconceptions touted as fact.
Solid cleansers don’t necessarily = greener
This misconception is more of a formula misconception, rather than surfactant one. But it’s so widespread that I thought it was important to raise here.
There are many reasons liquid products may come out on top from an environmental performance standpoint.
1) The greatest contributor to environmental impact for cleansing products in their life cycle tends to be at the consumer use phase – specifically how much water (especially warm) is needed to effectively use the product (lots of research here on laundry detergents). Solid cleansers typically translate to more water usage from consumers. This was recently explored via an LCA in the context of toothpaste tabs vs toothpaste in tubes – for this reason, the regular toothpaste came out on top.
2) We know in other product formats, such as O/W lotions, the ingredient types that contribute the most to formulation environmental impacts are the emollients (e.g. oils). Structuring agents are often based on oil feedstocks, and solid formats require more of those ingredients to create the structure. Below is a depiction of the CO2 equivalent % contributions of different raw material types in formulas, provided by Evonik, that I think depicts this very well.
3) Finished products are often manufactured closer to their final consumer, which may reduce the importance of transportation weight for environmental performance compared to other things (such as the above).
Did you know? One of Unilever’s current strategies for meeting their sustainability targets is encouraging consumers to switch from bar soaps to liquids. From their analysis, bar products have a greater sustainability impact than liquid formats, even considering the additional plastic packaging and water content.
DISCLAIMER, I am NOT saying solid=worse. But the blanket idea that they’re better is incorrect. These ideas were based on assumptions, demonstrating the importance of actually measuring these things.
Palm-free also ≠ greener
This one’s relevant to surfactants since the fatty carbon chains on them have to come from somewhere. Historically, that was from fossil fuels, but as demand increased for plant alternatives, that has shifted to predominantly palm and coconut feedstocks. These are the feedstocks things have shifted to because the oils have the right chemistry for surfactant production at scale.
Palm is a uniquely productive crop. Compared to other oilseeds, it requires fewer resources/land/water, with estimates of being 6-10x more efficient at producing oil on a per hectare basis. Specific to surfactants, these use palm kernel oil for their production, which is a byproduct of palm oil production. Historically this would have been waste, but the chemicals sector created value in it by turning what would otherwise be waste into a co-product.
With the palm=bad narratives, there has been a push to use different oil seeds. For surfactants specifically, considering the chemistry needs, coconut has been often viewed as the alternative. We already knew coconut was less efficient and was similarly grown in richly biodiverse regions. More evidence is starting to come out that coconut may actually have a larger impact – a case of regrettable substitutions….
Yes, there are obviously issues with palm supply right now and historically. The path forward probably isn’t to just abandon the crop and reach for alternatives (that will likely have a higher impact in the end). The Round Table for Responsible Palm Oil has been doing a lot of good work trying to improve palm sustainability – it’s a very large and complex challenge. At the end of the day, the blanket statement that palm=bad probably has done more harm than good.
Why is it in a formulators’ (and the greater cosmetics industry’s) best interest to correct these misconceptions when we have the opportunity?
Because misinformation tends to snowball, and that creates huge hurdles for the beauty space!
These hurdles include:
Distorted market demand. Consumers are now expecting formulations based on these misconceptions.
These distorted demands lead to R&D inefficiencies. To meet these expectations, we need to spend more time developing “safe sounding” formulas, rather than formulas that are actually better (by any metric). We also have to continuously invest in reformation with a more limited, and expensive, palette of ingredients to work with.
They’ve also led to a patchwork of legislation that isn’t necessarily aligned with science. There are so many examples of this happening. For example, in Hawaii with the UV filter bans to save coral reefs, or over in Washington State – they think formaldehyde donor preservatives are the same thing as adding straight up formaldehyde to formulas (THEY ARE NOT!).
Not to mention the changing retailer standards that tends to force companies into formula constraints. This is especially pernicious with smaller companies whose success hinges on sometimes getting onto those store shelves with the bunk standards (e.g. Sephora or Credo).
And this all translates to a significantly higher cost for everyone to do business. Formulas and product development are more expensive, as are compliance costs, as are the costs associated with the increasing risk of being sued – especially if you operate in the USA.
The insights from this post are based on the roundtable discussion I moderated last year at the ICIS World Surfactants Conference on behalf of the Independent Beauty Association. A conversation about finding truth in beauty, with a spotlight on surfactants. Featuring Dennis Abbeduto from Colonial Chemical, Claire McGahan from Stepan Company and Women in Chemicals, and Neil Burns. Find the full discussion in a podcast format here: https://www.theecowell.com/podcast/truthinbeautysurfactantsedition
Additional references
Chandler, M., & O’Lenick, T. (2019). Inverting the tables on emulsion sensory and performance. Household and Personal Care Today, 14(2).
Domokos, A., Nagy, B., Szilagyi, B., Marosi, G., & Nagy, Z. K. (2021). Integrated continuous pharmaceutical technologies—a review. Organic Process Research & Development, 25(4), 721-739.
Evans, T. (2015). Quantifying Hair Color Fading. Cosm & Toil. 130(1):30–5.
Evonik (Anna Howe). (2022). Substantiating Ingredient & Formulation Sustainability. Presentation at The Eco Well’s Sustainable Beauty E-Summit. https://www.youtube.com/watch?v=VGO2AzpxAmE
GH Lab Product Testing writeup. https://www.goodhousekeeping.com/beauty/hair/g3878/best-shampoo-for-colored-hair/
Meijaard, E., Abrams, J. F., Juffe-Bignoli, D., Voigt, M., & Sheil, D. (2020). Coconut oil, conservation and the conscientious consumer. Current Biology, 30(13), R757-R758.
Meijaard, E., Virah-Sawmy, M., Newing, H. S., Ingram, V., Holle, M. J. M., Pasmans, T., … & Sheil, D. (2024). Exploring the future of vegetable oils.
Suppipat, S., Hu, A. H., Trinh, L. T., Kuo, C. H., & Huang, L. H. (2022). A comparative life cycle assessment of toothpaste cream versus toothpaste tablets. Sustainable production and consumption, 29, 357-369.
