The Truth About What Soap Does to Your Skin

The Harsh Side Effects of Soap

young man washing face in sink
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Depending on the products you use, washing your face can cause more harm than good. Have you ever gotten that uncomfortably dry, tight feeling immediately after cleansing? You just washed your face... Shouldn't your skin feel amazing?

Instead, it might feel tight. Maybe it's irritated and itchy, or maybe it's red. Truth is, the ingredients some cleansers contain can have some pretty unpleasant side effects on skin.

Facial cleansers are designed to remove dirt, sweat, sebum and oils from the skin, and they are able to do so with the use of surfactants. Surfactants, short for "surface-active agents", work by surrounding dirt and oil, dissolving the particles and removing them as water runs over the skin. They also aid in then skin's natural exfoliating process.

Surfactants are chemical ingredients that have many different functions: they act as detergents, wetting agents, foaming agents, conditioning agents, emulsifiers, and solubilizers. In addition to facial cleansers, they can also be found in lotion, perfume, shampoo and a multitude of other haircare products.

The surfactants found in facial cleansers are meant to leave users with clean, beautiful skin, but that isn't always the result. They can have harmful effects on the stratum corneum, or the outermost layer of the epidermis, including:

  • After-wash tightness (AWT)
  • Dryness
  • Damage to the barrier function of the skin
  • Redness
  • Irritation
  • Itching

How Cleansers Interact with the Stratum Corneum

In order to fully understand the ways surfactants irritate skin, it's helpful to understand how cleansers interact with the various elements of the stratum corneum. The stratum corneum is the outermost layer of the epidermis.

It's made up of layers of dead keratinocytes, or protein cells, that are constantly shedding. Once a single layer of keratinocytes reaches the outermost layer of the stratum corneum, they become corneocytes.

When a keratinocyte turns into a corneocyte, the cell loses its nucleus and cytoplasm. The cell becomes hard and dry. Cleanser surfactants bind to these proteins and over-hydrate them, causing them to swell. The swelling allows the cleanser ingredients to more easily penetrate into the deeper layers of the skin, where they can potentially interact with nerve endings and the immune system, leading to itching and irritation. After the water evaporates corneocytes are drier than before, and that dryness can last. Cleansers can cause a reduction in the skin's natural moisturizing factor.

The Effects of Surfactants on Lipids

The stratum corneum also contains lipids that help skin retain moisture. The exact effects of cleansers on these lipids are still not completely understood. Research tells us that certain surfactants are able to get in between lipid bilayers, which disrupts the bilayer and increases permeability. Surfactants can also damage the lipid structures themselves, causing a reduction in the amount of lipids in the skin.

Cleansers and pH Levels

Surfactants are broadly divided into two categories: soap-based surfactants and synthetic, detergent-based surfactants, also known as syndets. Soap-based cleansers tend to have a pH level of approximately 10, making them much more alkaline than syndets, which are typically pH 7 or lower. It appears that higher pH levels in soap are a key contributor to skin irritation seen with surfactant cleanser use. The exact way in which this irritation occurs is unknown.

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