The Cleansing Engine: Understanding Surfactants in Syndets

For thousands of years, humans relied on traditional soap—the alkali salts of fatty acids produced through saponification—to clean their skin, hair, and clothes. But as we explored in our previous series on soap versus syndets, traditional soap has fundamental incompatibilities with both skin and hair chemistry. The solution was not to abandon cleansing altogether, but to design better cleansing molecules: synthetic detergents, or syndets.

At the heart of every syndet formulation lies the surfactant—the surface-active agent that does the actual work of removing dirt, sebum, and environmental grime. But not all surfactants are created equal. Some are too harsh, stripping away the structural lipids and proteins your skin needs to stay hydrated and intact. Others are so gentle they barely cleanse at all, leaving you feeling greasy and unsatisfied. The formulator's challenge is to choose surfactants that balance efficacy with mildness, lather with barrier preservation, cost with performance.

This is the science of surfactant selection: understanding molecular size, electrical charge, and synergistic interactions. Whether you are formulating a face wash, a shampoo bar, a body cleanser, or even a dish soap, the principles remain the same. The difference lies in how aggressively you need to cleanse—and how much you can afford to damage the surface you are cleaning.

What is a Surfactant?

The word "surfactant" is short for surface active agent—a molecule that reduces the surface tension between two phases, such as oil and water. Surfactants are amphiphilic, meaning they have two distinct regions: a hydrophobic (water-repelling) tail, typically a long hydrocarbon chain, and a hydrophilic (water-loving) head, which may be charged or uncharged depending on the surfactant type.

When surfactants are added to water at sufficient concentration, they spontaneously organize into spherical structures called micelles. In a micelle, the hydrophobic tails cluster together in the center, away from the water, while the hydrophilic heads face outward, interacting with the aqueous environment. This arrangement allows the micelle to encapsulate oily dirt and sebum in its hydrophobic core, suspending it in water so it can be rinsed away.

This is the fundamental mechanism of all detergent cleansing: micelle formation (An Easy Guide to Understanding How Surfactants Work, IPC). Without micelles, oil and water do not mix. With them, we can wash away the grime of daily life. But the size, charge, and structure of those micelles determine whether the surfactant cleanses gently—or destroys the barrier it touches.

The Three Classes: Charge Matters

Surfactants are classified by the electrical charge (or lack thereof) on their hydrophilic head group. This charge determines how the surfactant interacts with skin, hair, and other surfaces—and whether it will be irritating or mild.

Anionic Surfactants

Anionic surfactants carry a negative charge on their head group. They are the workhorses of the cleansing industry: highly effective at removing sebum and oils, producing abundant foam, and relatively inexpensive to manufacture. The vast majority of shampoos, body washes, and household cleaners rely on anionic surfactants as their primary cleansing agent.

Common anionic surfactants include: - Sodium Lauryl Sulfate (SLS) - Sodium Laureth Sulfate (SLES) - Sodium Cocoyl Isethionate (SCI) - Sodium Lauryl Sulfoacetate (SLSa) - Sodium Coco Sulfate (SCS)

The problem with many anionic surfactants is their tendency to denature proteins and extract lipids from the skin or hair surface, disrupting barrier integrity and increasing transepidermal water loss (TEWL). The smaller the molecule, the more aggressive this effect becomes.

Non-Ionic Surfactants

Non-ionic surfactants carry no electrical charge. Instead, their hydrophilic head is typically composed of polyethylene oxide chains or sugar groups that form hydrogen bonds with water. Because they lack charge, non-ionic surfactants do not interact as strongly with the negatively charged proteins on skin and hair, making them exceptionally mild.

Common non-ionic surfactants include: - Decyl Glucoside - Coco Glucoside - Lauryl Glucoside (all members of the alkyl polyglucoside family) - Polysorbates - Cocamide MEA/DEA

Non-ionic surfactants are often used in baby shampoos and sensitive skin formulations because they produce minimal irritation. However, they also produce less foam and less aggressive cleansing than anionic surfactants, which is why they are typically used as co-surfactants rather than primary cleansing agents.

Amphoteric (Zwitterionic) Surfactants

Amphoteric surfactants carry both a positive and a negative charge on the same molecule, and their net charge depends on the pH of the solution. In acidic environments, the molecule is positively charged (cationic). In alkaline environments, it is negatively charged (anionic). At a certain pH—called the isoelectric point—the positive and negative charges balance out, and the surfactant carries no net charge.

The most widely used amphoteric surfactant in cosmetics is Cocamidopropyl Betaine (CAPB), a derivative of coconut oil. Amphoteric surfactants are rarely used as primary cleansers on their own, because they are relatively weak at removing oils. Instead, they are formulated alongside anionic surfactants to mitigate irritation, boost foam, and increase viscosity—a phenomenon we will explore in the section on synergy.

The Danger of Small Molecules: SLS & SLES

Sodium Lauryl Sulfate (SLS) and its ethoxylated cousin, Sodium Laureth Sulfate (SLES), are among the most widely used surfactants in the world. They are cheap, effective, and produce copious amounts of foam. They are also among the most irritating surfactants approved for cosmetic use—not because they are inherently toxic, but because they are too efficient.

The problem with SLS is not its cleansing ability. The problem is its molecular size.

Molecular Size and Skin Penetration

The outermost layer of the skin—the stratum corneum—acts as a barrier to protect the body from environmental insults and prevent water loss. This barrier is composed of dead, flattened skin cells (corneocytes) surrounded by a lipid-rich "mortar" of ceramides, cholesterol, and free fatty acids. Within this structure are tiny aqueous pores, channels filled with water that allow for the diffusion of small water-soluble molecules.

Research has shown that the average diameter of these aqueous pores in the stratum corneum is approximately 29 ± 5 Ångströms (Ananthapadmanabhan et al., 2004). Now consider the size of SLS micelles: approximately 15-20 Ångströms in radius. These micelles are small enough to penetrate through the aqueous pores of the stratum corneum, allowing the surfactant to reach the deeper layers of the epidermis where it can interact with living cells, structural proteins, and lipid membranes.

When SLS penetrates the skin barrier, it does not simply wash away surface dirt—it begins to denature proteins by disrupting hydrogen bonds and hydrophobic interactions in their tertiary structure. This protein denaturation causes keratinocytes to swell and exposes new water-binding sites, leading to an initial hyper-hydration of the stratum corneum (Kubota et al., 2021). Over time, this swelling disrupts the "brick and mortar" structure of the barrier, increasing permeability and allowing water to escape through transepidermal water loss (TEWL).

Studies have documented that even brief exposure to SLS significantly increases TEWL. In one controlled experiment, TEWL increased from a baseline of 5.1 g m⁻² h⁻¹ to 42.6 g m⁻² h⁻¹ following SLS exposure—an eight-fold increase (Ananthapadmanabhan et al., 2004). The result is dry, tight, irritated skin that has lost its ability to retain moisture.

SLES, while slightly milder than SLS due to the ethoxylation process that increases its molecular size, still presents similar issues at high concentrations. Both surfactants are effective—perhaps too effective—at stripping away not just dirt, but the very lipids and proteins that keep your skin intact.

Why "Efficient" Cleansing is Destructive

From a formulation perspective, the irritation potential of a surfactant is directly related to its ability to extract lipids and denature proteins. Charged surfactants adsorb to skin proteins, causing them to swell and denature, while simultaneously dissolving the intercellular lipids that hold the stratum corneum together (Kubota et al., 2021). This is not a bug—it is the feature. The more effectively a surfactant can disrupt lipid bilayers and unfold proteins, the better it is at removing oily residues from surfaces.

For dishes, this is ideal. For living skin and hair, it is catastrophic.

This is why the cosmetic chemistry community has spent decades searching for large-molecule surfactants—anionic cleansers that are effective at forming micelles and removing sebum, but physically too large to penetrate the skin barrier and cause damage.

The Large Molecule Solution: SCI & SLSa

The breakthrough came with the development of surfactants whose micellar structures are larger than the aqueous pores of the stratum corneum. If the surfactant cannot penetrate the barrier, it cannot denature the proteins and extract the lipids beneath the surface. It remains on the surface, performing its cleansing function exactly where it is needed—and nowhere else.

Sodium Cocoyl Isethionate (SCI): The "Baby Foam" Surfactant

Sodium Cocoyl Isethionate (SCI) is an anionic surfactant synthesized by reacting coconut fatty acids with isethionic acid. It is the primary cleansing agent in countless "mild" cleansers, including the iconic Dove Beauty Bar, and is widely regarded as one of the gentlest anionic surfactants available for skin care.

The secret to SCI's mildness lies in its micelle size. Dynamic light-scattering studies have measured the radius of SCI micelles at approximately 33.5 ± 1 Ångströms—significantly larger than the 29 ± 5 Ångström pores of the stratum corneum (Ananthapadmanabhan et al., 2004). Because the SCI micelles are too large to penetrate through the skin's aqueous pores, they remain on the surface, gently lifting away dirt and sebum without disrupting the barrier structure beneath.

In vitro and in vivo studies have demonstrated that SCI is substantially less damaging to the skin barrier than SLS. Skin penetration studies show that SCI absorption is dose-independent, meaning that even at high concentrations, the surfactant does not increase its penetration into the skin—strong evidence that the larger micelles simply cannot fit through the pores (Ananthapadmanabhan et al., 2004). This is in stark contrast to SLS, where penetration increases with concentration, leading to cumulative barrier damage.

SCI also produces a rich, creamy, stable lather—a sensory quality that consumers associate with effective cleansing. It is this combination of mildness and performance that has made SCI the formulator's first choice for solid shampoo bars, syndet body bars, and facial cleansers. It is often sold in the form of a fine white powder or small "noodles" that must be carefully processed to form a solid bar.

Sodium Lauryl Sulfoacetate (SLSa): The Hard Water Champion

Sodium Lauryl Sulfoacetate (SLSa) is frequently confused with Sodium Lauryl Sulfate (SLS) because of the similar names, but they are chemically and functionally distinct. The key difference lies in the sulfoacetate functional group, which replaces the sulfate ester found in SLS. This seemingly small change results in a much larger molecular structure and dramatically different performance characteristics.

Like SCI, SLSa micelles are too large to penetrate the stratum corneum, making them mild and non-irritating (CIR Expert Panel, 2019). The Cosmetic Ingredient Review (CIR) Expert Panel reviewed updated exposure data and reaffirmed that SLSa is safe as used in cosmetics, with no evidence of significant skin irritation at typical use concentrations.

What sets SLSa apart from SCI is its exceptional performance in hard water. While SCI performs well in most water conditions, SLSa is known for producing abundant, stable lather even in the presence of high concentrations of calcium and magnesium ions—conditions that would cause traditional soap to form soap scum and SCI to lose some of its foaming power. This makes SLSa particularly attractive for formulations intended for use in regions with hard water, or in products like bath bombs and shower steamers where performance in mineral-rich bathwater is critical.

The primary drawback of SLSa is its cost. It is significantly more expensive than SCI, which limits its use in budget-friendly formulations. However, for premium products where lather performance and mildness are non-negotiable, SLSa is unmatched.

The Sulfate Caveat: Sodium Coco Sulfate (SCS)

Sodium Coco Sulfate (SCS) occupies an interesting middle ground in the surfactant landscape. It is often marketed as a "natural" or "gentle" alternative to SLS, and in some respects, this is true. But it is not without caveats.

What is SCS?

Unlike SLS, which is synthesized using only isolated lauric acid (a C12 fatty acid), SCS is produced using the entire fatty acid profile of coconut oil. This includes lauric acid (C12), but also capric (C10), caprylic (C8), myristic (C14), palmitic (C16), stearic (C18), and oleic (C18:1) acids. The result is a complex blend of sulfate surfactants with varying chain lengths.

Because SCS contains the full spectrum of coconut fatty acids, it contains approximately 50% SLS by composition (Chagrin Valley Soap & Salve). The remaining 50% is made up of longer-chain sulfates, which are generally milder and less irritating than lauric-based surfactants.

Is SCS Milder Than SLS?

The evidence suggests that SCS is mildly less irritating than pure SLS, but the difference is not dramatic. A peer-reviewed study found that SCS has approximately 15% lower skin irritation potential than SLS (ResearchGate, 2019). This reduction is attributed to the larger molecular size of the blended surfactants and the "dilution" of the highly irritating C12 lauryl chain with longer, milder chains.

However, the lauryl (C12) chain remains the most irritating tail length in the sulfate family because it occupies a problematic middle ground: it is long enough to be difficult to rinse off, but short enough to penetrate the skin barrier (Nyponros). This means that even though SCS contains other fatty acids that are milder, the presence of lauric sulfate ensures that it still carries significant irritation potential—especially at high concentrations or with prolonged contact.

Where SCS Fits in Formulation

SCS is often used in "green" or "natural" formulations because it is undeniably plant-derived and biodegradable. It produces large, fluffy bubbles and cuts through sebum and oil effectively. However, formulators must be cautious. SCS should not be used as a standalone surfactant in leave-on or high-concentration rinse-off products. Instead, it is best formulated in combination with buffering co-surfactants like CAPB or decyl glucoside to reduce its irritation potential.

In the Potionologie formulation philosophy, we view SCS as a situational ingredient—useful in specific contexts where cost constraints or natural certification requirements demand it, but never our first choice for mildness-critical applications like facial cleansers or baby products.

The Co-Surfactant Synergy: Mixed Micelles

One of the most powerful tools in the formulator's arsenal is the strategic combination of surfactants with different charge types. When anionic and amphoteric (or non-ionic) surfactants are blended, they do not simply add their effects together—they interact to form mixed micelles, larger and structurally distinct aggregates that behave very differently from the individual surfactants alone.

This phenomenon, known as surfactant synergy, allows formulators to achieve the cleansing power of anionic surfactants while dramatically reducing irritation, increasing foam stability, and thickening the product—all without adding more active ingredients.

Cocamidopropyl Betaine (CAPB): The Amphoteric Ally

Cocamidopropyl Betaine (CAPB) is the most widely used amphoteric surfactant in cosmetic formulations. Derived from coconut oil and dimethylaminopropylamine, CAPB is a zwitterion, meaning it carries both a positively charged quaternary ammonium group and a negatively charged carboxylate group on the same molecule. Depending on the pH of the formulation, one charge may dominate, or they may balance out to give the molecule a near-neutral net charge.

On its own, CAPB is a weak cleanser—it produces minimal foam and does not effectively remove heavy sebum or oils. But when combined with anionic surfactants like SCI or SLS, something remarkable happens: mixed micelles form.

The Science of Mixed Micelles

When an anionic surfactant and an amphoteric surfactant are mixed in solution, their charged head groups interact electrostatically. The negative charge of the anionic surfactant and the positive charge of the amphoteric surfactant attract each other, causing the two types of molecules to co-assemble into larger, more stable micelles (Amphoteric and Anionic Surfactants, Chemists Corner).

These mixed micelles are not only larger in size—which reduces skin penetration—but also have a lower net charge density compared to micelles made purely of anionic surfactants. This reduced charge density means the micelles are less likely to bind to and denature skin proteins, resulting in significantly less irritation (Wolf et al., 2001).

Experimental data show that the optimal ratio of anionic to amphoteric surfactant for maximizing mildness and foam is approximately 2:1 (by weight of active solids). At this ratio, formulators observe: - Increased viscosity (the mixed micelles can form worm-like structures that thicken the product) - Enhanced foam volume and stability (smaller, creamier bubbles) - Reduced protein denaturation and irritation - Improved sensory feel on the skin

This is why virtually every modern "gentle" shampoo or body wash lists both an anionic surfactant (SLS, SLES, or SCI) and CAPB in the first few ingredients. The synergy between the two allows the formulator to deliver effective cleansing without the harsh stripping associated with anionic surfactants alone.

Decyl Glucoside: The Gentle Giant

Decyl Glucoside is a non-ionic surfactant belonging to the alkyl polyglucoside (APG) family. It is synthesized by reacting a fatty alcohol (decyl alcohol, derived from coconut or palm) with glucose (from cornstarch or other plant starches). The result is a surfactant with a hydrophobic C10 tail and a hydrophilic sugar head group.

Because it carries no electrical charge, Decyl Glucoside does not interact strongly with proteins or lipids, making it one of the mildest surfactants available. The Cosmetic Ingredient Review (CIR) Expert Panel assessed 19 alkyl glucosides, including Decyl Glucoside, and concluded that they are safe and non-irritating at typical use concentrations (CIR, n.d.).

Decyl Glucoside is commonly used in: - Baby shampoos, where mildness is the top priority - Sensitive skin cleansers, where even SCI might be too aggressive - Natural and eco-certified products, as it is biodegradable and derived entirely from renewable plant sources

Like CAPB, Decyl Glucoside functions best as a co-surfactant rather than a primary cleanser. It produces moderate foam and can boost the lather of anionic surfactants while simultaneously reducing their irritation potential. It also contributes to the overall stability and sensory feel of the formulation, creating a smooth, silky lather that rinses cleanly without residue.

Choosing the Right Surfactant for the Application

Not all cleansing tasks are created equal. The surfactants you choose depend on what you are cleaning, how aggressively you need to clean it, and how much damage you can afford to cause in the process.

Body Soap

Body skin is resilient. It has a thicker stratum corneum than facial skin, secretes more sebum, and is less prone to visible irritation (though barrier disruption still occurs). Body cleansers need to remove environmental dirt, sweat, and excess sebum without stripping away the lipid barrier or elevating skin pH excessively.

Ideal surfactants: - Primary cleanser: SCI (33.5 Å micelles, mild, creamy lather) - Co-surfactant: CAPB (reduces irritation, boosts foam, increases viscosity) - Optional addition: Decyl Glucoside (for extra mildness in sensitive skin formulations)

Target pH: 4.5 - 5.5 (to match the skin's acid mantle and support the microbiome)

Facial Soap

Facial skin is thinner, more reactive, and more visible than body skin. Irritation on the face manifests as redness, tightness, peeling, and breakouts. Facial cleansers must be exceptionally mild—removing makeup, sunscreen, and surface oils without compromising barrier integrity.

Ideal surfactants: - Primary cleanser: SCI (gentle, effective) - Co-surfactant: Decyl Glucoside (non-ionic, extremely mild) - Optional addition: CAPB (if additional foam is desired)

Target pH: 4.5 - 5.5

Avoid: SLS, SLES, SCS (all too aggressive for facial use)

Shampoo Bars

Hair and scalp present a unique challenge. The scalp is living skin—it requires the same acid mantle preservation as the face and body. But the hair shaft is dead keratin, coated in a delicate lipid layer (the 18-MEA layer) that must be preserved to maintain shine and manageability. At the same time, the scalp produces significant sebum that must be removed to prevent fungal overgrowth (Malassezia) and dandruff.

Shampoo bars must cleanse more aggressively than body soap—but still at a hair-safe pH.

Ideal surfactants: - Primary cleanser: SCI (large molecule, effective sebum removal) - Co-surfactant: CAPB (reduces cuticle lifting, improves slip) - Alternative primary cleanser: SLSa (for hard water regions or extra cleansing power)

Target pH: 4.5 - 5.5 (to flatten the cuticle and preserve the 18-MEA layer)

We will explore the specific formulation considerations for hair and scalp in Part 3 of this series.

Hand Soap

Hands are washed frequently—often 10-20 times per day for healthcare workers, food handlers, and parents of young children. This repeated exposure means that even mild surfactants can cause cumulative barrier damage. Hand soap formulations must prioritize mildness and rapid rinsing over aggressive cleansing.

Ideal surfactants: - Primary cleanser: SCI or Decyl Glucoside - Co-surfactant: CAPB

Avoid: SLS, SCS (too harsh for high-frequency use)

Dish Soap

Dishes are not alive. They do not have a barrier to protect. Dish soap needs to remove baked-on grease, food residues, and oils as efficiently as possible. This is where aggressive anionic surfactants excel.

Ideal surfactants: - Primary cleanser: SLS, SLES, or SCS (maximum grease-cutting power) - Co-surfactant: CAPB or non-ionic surfactants (to improve foam stability and reduce greasy feel on hands)

Target pH: Neutral to slightly alkaline (7.0 - 9.0) for enhanced degreasing

Laundry Detergent and General Purpose Cleaning

Laundry and household cleaning prioritize cost-effectiveness, efficiency, and environmental impact. These products do not come into prolonged contact with skin, so irritation is less of a concern (though it is not irrelevant for those with sensitive skin). The focus shifts to biodegradability, hard water tolerance, and the ability to remove a wide range of stains (protein, oil, pigment).

Ideal surfactants: - Primary cleanser: SCS, SLES, or linear alkylbenzene sulfonate (LABS) - Co-surfactant: Non-ionic surfactants (alcohol ethoxylates, alkyl polyglucosides) - Hard water chelators: Citric acid, EDTA, or zeolites

Target pH: Slightly alkaline (8.0 - 10.0) for maximum soil removal

The Potionologie Approach

At Potionologie, we formulate with intention. Every ingredient is chosen not because it is trendy or "natural," but because its chemistry aligns with the biology of what we are trying to clean—and what we are trying to preserve.

For our body syndet bars, we use SCI as the primary cleanser, buffered with CAPB to create mixed micelles that cleanse effectively without disrupting the stratum corneum. We formulate at a pH of 4.5 - 5.5 to protect the acid mantle and support the skin microbiome. We avoid SLS, SLES, and SCS entirely in body and facial products—not because they are "toxic," but because they are incompatible with long-term barrier health.

For our shampoo bars, we use the same SCI + CAPB combination, but at slightly higher concentrations to handle the sebum load of the scalp. We incorporate superfatting oils (such as jojoba or babassu) to deposit a protective lipid layer onto the hair shaft during rinsing, compensating for the sebum that must be removed to prevent dandruff. We test every formulation in hard water to ensure it rinses cleanly without buildup.

We choose SCI over SLSa not because SLSa is inferior—it is an excellent surfactant—but because the cost differential is significant, and for most customers, SCI performs beautifully. In future limited-edition formulations or specialty bars designed explicitly for hard water regions, we may explore SLSa. But we never compromise on mildness.

This is not marketing. It is chemistry. And it is the difference between formulation and guesswork.

Conclusion

Surfactants are the cleansing engines of modern cosmetic chemistry. They are the molecules that allow us to wash away the dirt and oils of daily life without resorting to the alkaline harshness of traditional soap. But not all surfactants are created equal.

The smallest molecules—SLS and SLES—are effective cleansers, but they penetrate the skin barrier and cause protein denaturation, lipid extraction, and increased TEWL. The larger molecules—SCI and SLSa—remain on the surface, cleansing effectively without barrier disruption. The blended molecules—SCS—occupy a middle ground, milder than SLS but still requiring careful buffering. And the co-surfactants—CAPB and Decyl Glucoside—transform harsh cleansers into mild, synergistic systems through the formation of mixed micelles.

The formulator's job is not to choose the most "natural" surfactant, or the cheapest, or the trendiest. It is to choose the surfactant whose molecular size, charge, and micellar behavior align with the task at hand. For living skin and hair, that means large molecules, mixed micelles, and a relentless focus on barrier preservation.

In Part 2 of this series, we will explore how to apply these principles specifically to body cleansers, diving deeper into the brick-and-mortar structure of the stratum corneum, the role of the acid mantle, and how to formulate for a healthy skin microbiome.

For now, it is enough to understand that the surfactant is not just "the thing that makes bubbles." It is the cleansing engine—and the success or failure of your formulation depends on choosing the right one.

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References

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Ananthapadmanabhan, K.P., Lips, A., Vincent, C., Meyer, F., Caso, S., Johnson, A., Subramanyan, K., Vethamuthu, M., Rattinger, G., & Schafer, F. (2013). Stratum corneum fatty acids: Their critical role in preserving barrier integrity during cleansing. International Journal of Cosmetic Science, 35(4), 337-345. https://doi.org/10.1111/ics.12042

Blaak, J., Staib, P., Kendall, A.C., Nicolaou, A., & Gijsbers, J.W. (2022). The impact of daily facial cleansing on the lipid barrier in individuals with a sensitive skin. Skin Research and Technology, 28(2), 243-251. https://doi.org/10.1111/srt.13124

Cosmetic Ingredient Review (CIR) Expert Panel. (2019). Safety Assessment of Sodium Lauryl Sulfoacetate as Used in Cosmetics. Retrieved from https://www.cir-safety.org/sites/default/files/RR_Sodium%20Lauryl%20Sulfoacetate.pdf

Cosmetic Ingredient Review (CIR) Expert Panel. (n.d.). Safety Assessment of Alkyl Glucosides as Used in Cosmetics. Retrieved from https://www.cir-safety.org/

IPC. (n.d.). An Easy Guide to Understanding How Surfactants Work. Retrieved from https://ipcol.com/blog/an-easy-guide-to-understanding-surfactants/

Kubota, K., Okuda, M., Noro, Y., Sekimoto, M., Kojima, H., & Kusakari, Y. (2021). The involvement of protein denaturing activity in the effect of surfactants on skin barrier function. Skin Research and Technology, 27(4), 542-548. https://doi.org/10.1111/srt.12939

ResearchGate. (2019). Sodium Lauryl Sulfate vs. Sodium Coco Sulfate: Study of the Safety of Use Anionic Surfactants with Respect to Their Interaction with the Skin. Retrieved from https://www.researchgate.net/publication/331789745

Wolf, R., Wolf, D., Tüzün, B., & Tüzün, Y. (2001). Soaps, shampoos, and detergents. Clinics in Dermatology, 19(4), 393-397. https://doi.org/10.1016/s0738-081x(01)00188-2

Chemists Corner. (n.d.). Amphoteric and Anionic Surfactants - How to Use Together. Retrieved from https://chemistscorner.com/cosmeticsciencetalk/discussion/amphoteric-and-anionic-surfactants-how-to-use-together/

Chagrin Valley Soap & Salve. (n.d.). Sodium Coco Sulfate: Is It Natural? Retrieved from https://www.chagrinvalleysoapandsalve.com/blogs/idas-soap-box-blog/sodium-coco-sulfate-is-it-natural

Nyponros. (n.d.). Why Sodium Coco-Sulfate is Just as Bad as SLS. Retrieved from https://nyponros.com/en/soap-and-other-surfactants/sodium-coco-sulfate-in-shampoo