Skin is the largest organ of the body and has many roles. As well as being in constant communication with many of the body’s other systems such as the immune, nervous and hormonal systems, it also participates in many of the processes which are vital for good health such as regulating body temperature.

One of the main functions of the skin is a protective barrier separating delicate internal organs from the harsh external environment (1).  It's a tough job, as exposure to pollutants and toxins, changes in climate along with general wear and tear over time may take a toll on the appearance as well as the function of the skin. So, what can you do to help your skin in its protective role?

One way to support the skin is to keep it well hydrated as it’s constantly losing moisture through evaporation. This leads to a gradual decrease of moisture content from both the deepest layers of the skin, which have moisture levels of 75-85%, to the surface which has only 10-20% (2, 3). Depending on temperature and humidity, as much as half a litre a day can be lost – even without sweating (3). This process is called Trans-epidermal Water Loss or TEWL for short. It’s when water passes from the dermis through the epidermis and evaporates from the skin’s surface.  It's a process that your skin naturally regulates but it’s crucial in maintaining hydration of the outer layer of the skin. If in good condition and undamaged, this layer can retain enough moisture to perform its protective role (3). If there is not enough or this layer is damaged, it becomes unable to retain water resulting in dry and dehydrated skin. It also loses its elasticity and starts to flake and crack. This not only affects the smooth look of the skin but its barrier function making it susceptible to damage and irritation (2, 3).

If your skin is getting too dry, you can protect its natural, oily film by using mild cleansers instead of harsh soaps and wash with warm water instead of hot. To keep moisture inside the outer layer of your skin, pat it dry instead of rubbing leaving it slightly damp before applying a good quality moisturiser.  With so many products on the market, it may take time to find the right one for you but it’s worth the effort!  Remember also to use gloves when it is cold or when using detergents and protect the skin from the sun (4-6).

Maintaining a healthy lifestyle helps your skin too along with minimising stress and stopping smoking (4). There are also other lifestyle factors which though as yet unproven, are worth a closer look. Drinking more water seems to help the hydration of the skin, improving its texture, particularly amongst those with low daily water consumption (7, 8). Physical activity also seems to help as more active people tend not just to have better hydrated skin but exercise also improves its ability to retain moisture (9).

References

1. Chuong CM, Nickoloff BJ, Elias PM, Goldsmith LA, Macher E, Maderson PA, et al. What is the 'true' function of skin? Exp Dermatol. 2002;11(2):159-87.
2. Jiang B, Jia Y, He C. Promoting new concepts of skincare via skinomics and systems biology-From traditional skincare and efficacy-based skincare to precision skincare. J Cosmet Dermatol. 2018;17(6):968-76.
3. Jansen van Rensburg S, Franken A, Du Plessis JL. Measurement of transepidermal water loss, stratum corneum hydration and skin surface pH in occupational settings: A review. Skin Res Technol. 2019;25(5):595-605.
4. Mayo Clinic. Skin care: 5 tips for healthy skin. Good skin care — including sun protection and gentle cleansing — can keep your skin healthy and glowing 2019 [Available from: https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/skin-care/art-20048237.
5. American Academy of Dermatology. DRY SKIN: TIPS FOR MANAGING - Self Care  [Available from: https://www.aad.org/public/diseases/a-z/dry-skin-self-care.
6. Harvard Health Publishing. Moisturizers: Do they work? 2019 [Available from: https://www.health.harvard.edu/staying-healthy/moisturizers-do-they-work.
7. Palma L, Marques LT, Bujan J, Rodrigues LM. Dietary water affects human skin hydration and biomechanics. Clin Cosmet Investig Dermatol. 2015;8:413-21.
8. Akdeniz M, Tomova-Simitchieva T, Dobos G, Blume-Peytavi U, Kottner J. Does dietary fluid intake affect skin hydration in healthy humans? A systematic literature review. Skin Res Technol. 2018;24(3):459-65.
9. Ryosuke O, Yoshie S, Hiromi A. The association between activity levels and skin moisturising function in adults. Dermatol Reports. 2021;13(1):8811.