EXCESS HYGIENE AND THE SKIN 

Cleansing is often the first step to our skin care routine, especially in the evening time to help remove make-up and daily pollutants that interact with the skin. It usually contains a surfactant (or soap) that helps bind a wide variety of molecules and lift them from the epidermis to be washed away [1]. However, cleansing too often, or with the wrong type of cleanser, and failing to moisturize after can ultimately damage the skin barrier. To complicate matters further, there are hundreds of surfactants and endless combinations of surfactants, moisturizing agents, preservatives, and fragrances that compose the many cleansers we see on the market today. So, how often should we cleanse and how do we choose the right cleanser?

SKIN BARRIER DISRUPTION 

The cleansing properties of a face wash are largely attributed to the type of surfactant used in formulation. Surfactant, literally meaningsurfaceactive agent, works by interfering with protein-protein and protein-lipid interactions in the cell membrane [2]. Traditionally, they have a negatively charged, hydrophilic “head” and an uncharged, hydrophobic “tail” [3]. This allows them to integrate within and disrupt the molecular interactions between our cells, make-up, debris, and bacteria that all reside on the stratum corneum. The charged head interacts with water molecules while the lipophilic tail integrates into the cellular lipid membrane and together, brings water into deeper layers of the epidermis [4]. As dermatologist Dr. Draelos explains, “Following the completion of washing, the excess water evaporates leading to skin tightness and dryness because the soap binding reduces the ability of the skin proteins to hold water.” 

pH is another critical factor that governs how cleansers leave the skin. While the pH of the skin barrier is naturally acidic (pH 4-6), harsher cleansers often have a high pH, up to 8 or 9. It’s best to use products with a more neutral pH, around 6 or 7 [5,6]. 

MICROBIOME DISRUPTION

In addition to skin barrier disruption, more recent research has focused on how different types of cleansers can either upset or help maintain the microbiome [7]. Although it is tempting, harsh cleansers should be avoided in cases of irritation, especially related to acne [8]. The barrier is already disrupted and further dehydrating it will slow healing. Using a mild cleanser paired with antimicrobial and keratolytic actives like niacinamide, retinol, or salicylic acid is better than manually scrubbing, which strips the skin. In fact, one study showed that just adding moisturizing ingredients to a cleanser supported growth of “good” bacteria while simultaneously diminishing the population of more inflammatory bacteria [9]. 

FINDING THE RIGHT REGIMEN

When cleansing, it is best to err on the side of mild. In the morning, we recommend using micellar water or very gentle, moisturizing cleansers with minimal foaming. In the evening and to remove makeup, select a double cleansing method in which the first cleanse is an oil-based cleanser that melts off make-up and the second cleanse is a mild surfactant-containing product [4]. 

Harsh surfactants to avoid include:

• Sodium Laurel Sulfate (SLS or SLES), 
• Sodium Dodecyl Sulfate (SDS), 
• Benzalkonium Chloride, 
• and Cetrimonium Bromide [10]. 

Instead, choose mild, amphoteric cleansing ingredients like coco or laurel glucoside, coacoaamidpropyl betaine or sodium cocoamphoacetate [11,12]. Cleansers should be simple and just effective enough to remove the build-up of the day. Save the expensive, potent actives for serums and moisturizers that will remain on the skin and provide hydration throughout the day or night. Because the environmental and genetic factors that influence our skin are so diverse, some trial and error will be necessary to find what works for you [13]. 

Sources: 

 [1] Fowler JF, Eichenfield LF, Elias PM, Horowitz P, McLeod RP (2013) The chemistry of skin cleansers: an overview for clinicians.Semin Cutan Med Surg 32, S25-27.

[2] Greber KE, Dawgul M, Kamysz W, Sawicki W, Łukasiak J (2014) Biological and surface-active properties of double-chain cationic amino acid-based surfactants.Amino Acids 46, 1893–1898.

[3] Schwuger MJ (1973) Mechanism of interaction between ionic surfactants and polyglycol ethers in water.Journal of Colloid and Interface Science 43, 491–498.

[4] Draelos ZD (2018) The science behind skin care: Cleansers.Journal of Cosmetic Dermatology 17, 8–14.

[5] Blaak J, Staib P (2018) The Relation of pH and Skin Cleansing.Curr Probl Dermatol 54, 132–142.

[6] Hawkins S, Dasgupta BR, Ananthapadmanabhan KP (2021) Role of pH in skin cleansing.Int J Cosmet Sci 43, 474–483.

[7] Sfriso R, Egert M, Gempeler M, Voegeli R, Campiche R (2020) Revealing the secret life of skin - with the microbiome you never walk alone.Int J Cosmet Sci 42, 116–126.

[8] Conforti C, Giuffrida R, Fadda S, Fai A, Romita P, Zalaudek I, Dianzani C (2021) Topical dermocosmetics and acne vulgaris.Dermatol Ther 34, e14436.

[9] Sfriso R, Claypool J (2020) Microbial Reference Frames Reveal Distinct Shifts in the Skin Microbiota after Cleansing.Microorganisms 8, E1634.

[10] Walters RM, Mao G, Gunn ET, Hornby S (2012) Cleansing Formulations That Respect Skin Barrier Integrity.Dermatol Res Pract 2012,.

[11] Stratia, INGREDIENT SPOTLIGHT: Surfactants.

[12] (2017) Update on Alkyl Glucosides.The Dermatologist 25,.