How does the layer work to protect the body?
- Get to Know The Types of Skin Protective Layers
- The Role of Skin in Regulating Water and Molecules
- How to Maintain Skin Moisture
The skin is the largest organ in the body that covers the entire surface of the body and functions as a barrier between the internal organs and the external environment. Its main function is to protect the body from pathogens, harmful chemicals, UV radiation, and physical injury to prevent direct harm to vital organs.
Get to Know The Types of Skin Protective Layers
The skin’s protective barrier consists of five layers: the outermost layer is the Stratum Corneum, which is made up of fats, ceramides, cholesterol, fatty acids, and other lipids. The next layer is the Stratum Granulosum, which produces keratinocytes for keratin formation and lipid synthesis, and where the secretion system occurs. The deeper layer, Stratum Spinosum, functions to maintain the structural integrity of the skin’s proteins.
Below this is the Stratum Basale, the deepest layer of the epidermis, where mitosis occurs and melanocytes are produced to create melanin, the pigment responsible for skin color. The last layer is the epidermal-dermal junction, which lies between the epidermis and the layer below it. This layer plays an important role in maintaining the strength and stability of the skin layers.
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The Role of Skin in Regulating Water and Molecules
The skin’s layers are responsible for regulating the movement of water and other molecules needed by the body. This process is known as trans-epidermal water loss (TEWL) and trans-epidermal permeability (TEP).
TEWL helps keep the skin hydrated by minimizing water evaporation, maintaining stable body temperature, and ensuring skin moisture is retained. On the other hand, TEP regulates the movement of molecules between the epidermis and deeper layers, including the bloodstream. Both are crucial and require adequate hydration to function optimally.
How to Maintain Skin Moisture
To maintain skin moisture, daily water intake must be met through drinking, washing the skin, and, when necessary, using moisturizers. Common active ingredients used to hydrate the skin include hyaluronic acid, ceramides, and squalane. In addition to active ingredients, skin care products also need the addition of supporting ingredients to enhance the product's effectiveness and stability.
These supporting ingredients, known as excipients, are adjusted based on the skin type and its function. Categories and examples of additives in skincare products include base ingredients or solvents, which serve to dissolve and deliver active ingredients. Examples include water, oils, and glycerin. Other additives include preservatives, emulsifiers, thickeners, stabilizers, fragrances, colorants, humectants, antioxidants, and chelating agents.
Not all of these ingredients are necessary for every product; they can be adjusted according to the product's needs and use, ensuring that the dosage is safe for the skin. The criteria for using a substance as an excipient are that it must be used in appropriate concentrations and should not cause irritation or allergic reactions. Generally, excipients are inactive, serving to support the performance of the main ingredients/active substances in the product.
However, there are several factors to consider, as certain excipients can have different effects on each individual. For example, emulsifiers used to stabilize oil and water can increase TEWL and decrease skin hydration, as they can interfere with the function of the lipid bilayer. Then, thickening agents that serve to increase the viscosity of fluids may disrupt the regulation of natural skin moisture due to their reduced absorption into the skin compared to liquid fluids.
Preservatives must also be ensured to be safe for skin sensitivity while still effectively preventing microbial growth. Some preservatives that require attention in their dosage include formaldehyde and parabens, as some individuals are sensitive to these compounds. The points outlined above are just examples of some excipients commonly used.
It is the responsibility of formulators and research teams to determine the positive and negative impacts of the compounds used in products on skin health. Formulating safe and effective skincare products is not enough just based on theory. Laboratory tests are needed to ensure that each ingredient used does not cause negative effects on the skin. Conduct thorough testing before the product is marketed so that skin protection is maintained and consumer confidence increases.
Author: Delfia
Editor: Sabilla Reza
References:
Ishiwatari S, Suzuki T, Hitomi T, Yoshino T, Matsukuma S, Tsuji,T. 2007. Effects of methyl paraben on skin keratinocytes. J Appl Toxicol. Vol 27:1–9.
Panwar, Aakash & Rathore, Priyanka. 2024. Impact of formulation excipients on skin barrier functions: A review. International Journal of Pharmaceutical Chemistry and Analysis. 11. 41-44. 10.18231/j.ijpca.2024.005.
