You may have asked yourself why there are so many different products for the skin on your face compared to those for the skin on the rest of your body. It’s obvious to us that our facial skin is different than the skin on our arms and legs which is different than the glabrous, or hairless, skin on our hands and feet but you may not know what biological phenomena are responsible for these differences. 

To answer these questions, we have to think about the functional purposes for these regions of our body. The soles of our feet and palms of our hand experience stronger mechanical forces and friction than any other part of the body so the stratum corneum, the outmost layer of the skin barrier, is incredibly thick in these regions [1]. This skin has a relatively high number of sweat glands and low number of barrier lipids making it very water permeable but less flexible, easily noticed by the “pruning” you experience after a long time submerged in water. The thickness and composition of the skin barrier on the torso, arms, and legs falls somewhere between that of the glabrous skin and facial skin [2]. This makes sense when we consider its main purpose is to protect our internal organs but to still allow for movement. Finally, the facial skin barrier is one of the thinnest on the body yet it is robust and extremely adaptable. The facial muscles needed to chew and express emotion require complex coordination that is allowed by the thin, flexible facial skin [3]. However, this thinness also makes facial skin more sensitive to water loss and physiochemical stress. 

For its size, the facial skin is more diverse than the skin on any other part of the body; the landscape of blood vessels, nerve endings, hair follicles, and the microbiome varies greatly from region to region at distances as small as 1 cm [4]. Additionally, the combination of high exposure to environmental aggressors (e.g.air pollutants and UV radiation) and continuous facial movement wears on the skin over time. Accumulation of this stress leads to redness, hyperpigmentation, texture, and wrinkles [5]. After considering the biological function of different parts of the body and accounting for all of the factors at play specific to the facial skin barrier, we can grasp why there are so many different facial skincare products: there are more opportunities for dysregulation. On the other hand, the thicker, relatively less complex skin barrier on the torso, arms, and legs is easier to protect and support.

That said, many of the same peptides, emollients, humectants, and occlusives found in skincare products are often found in body lotions, albeit the active ingredients are usually at lesser concentrations. Examples include collagen (peptide), squalene* (emollient), glycerin (humectant), silicones* (occlusive) and hundreds of others [6]. The truth is that because the skin barrier on your body is thicker and experiences less daily stress, it doesn’t require as much additional support besides sunscreen and a simple moisturizer. 

It is much easier for homeostasis of the thin facial skin barrier to be disrupted. This process is usually initiated by dehydration, followed by sensitization, and ends in redness and inflammation if the skin is unable to repair itself [7]. Thankfully, researchers and clinicians have identified and tested a wide swath of new and old active ingredients in the last 20 years [8]. With the rise of clean beauty products and science-driven skincare companies, safe and effective options exist for each of our individual skincare needs.

*BEAUTOLOGY LAB does not use petroleum-based or non-vegan ingredients in their products. These articles are for educational purposes only. 

Sources:

1. Tagami, H. Location-related differences in structure and function of the stratum corneum with special emphasis on those of the facial skin.International Journal of Cosmetic Science 30, 413–434 (2008).
2. Ya-Xian, Z., Suetake, T. & Tagami, H. Number of cell layers of the stratum corneum in normal skin - relationship to the anatomical location on the body, age, sex and physical parameters.Arch Dermatol Res 291, 555–559 (1999).
3. Westbrook, K. E., Nessel, T. A. & Varacallo, M. Anatomy, Head and Neck, Facial Muscles. inStatPearls (StatPearls Publishing, 2020).
4. Voegeli, R., Gierschendorf, J., Summers, B. & Rawlings, A. V. Facial skin mapping: from single point bio-instrumental evaluation to continuous visualization of skin hydration, barrier function, skin surface pH, and sebum in different ethnic skin types.Int J Cosmet Sci 41, 411–424 (2019).
5. Zhang, S. & Duan, E. Fighting against Skin Aging.Cell Transplant 27, 729–738 (2018).
6. Sethi, A., Kaur, T., Malhotra, S. & Gambhir, M. Moisturizers: The Slippery Road.Indian J Dermatol 61, 279–287 (2016).
7. Rosso, J. D., Zeichner, J., Alexis, A., Cohen, D. & Berson, D. Understanding the Epidermal Barrier in Healthy and Compromised Skin: Clinically Relevant Information for the Dermatology Practitioner.J Clin Aesthet Dermatol 9, S2–S8 (2016).
8. Espinosa-Leal, C. A. & Garcia-Lara, S. Current Methods for the Discovery of New Active Ingredients from Natural Products for Cosmeceutical Applications.Planta Med 85, 535–551 (2019).