by Danielle Sade
The skin and the circadian rhythm
Consider that the skin has its own bio-chronological clock. As the body’s internal environment changes throughout a 24-hour cycle, the skin responds differently to the environment. A good Aromatherapy skin care protocol relies on the foundational understanding of the formulation, the location and the timing the product is applied. Synchronizing these three can lead to higher efficacy of the formulation and prevent flare ups. Linking this awareness with the knowledge that Aromatherapy based formulations can also be designed to improve sleep cycles is paramount to healthy function skin! (Plikus et al., 2015)
What is the circadian rhythm?
The circadian rhythm is a 24-hour cycle in the physiological process in all living things, such as plants, animals, and humans. This, in turn, creates a personal biological clock controlled by a part of the brain that responds to light and darkness, sending signals through the eye's optic nerve. When exposed to light signals, the hypothalamus wakes up the body and prepares for daily physical functions through hormonal secretions, regulating body temperature and circulation. When the eyes are exposed to darkness, it signals to the brain to make you sleepy and prepare the body to repair and rejuvenate itself. Your skin works alongside this circadian biological clock, and so, understanding the normal, natural rhythms of your biological clock is a wonderful asset in any skincare program (Sade, 2017). (Plikus et al., 2015)
From 4 am-7 am your skin is building a natural protective barrier, and as a result, is not ideal for absorption or skin sensitivities. Because the skin is forming its natural protective barrier, thick active substances in cosmetics are unlikely to be absorbed. The skin tends to get irritated due to its higher histamine levels.
From 8 am-12 pm, the body is picking up pace, causing greater blood flow to the skin's surface and loading the skin with active compounds from the system. There is a substantially larger chance of experiencing an allergic reaction at this time.
From 1 pm-5 pm, the body slows down, and new cell tissues proliferate slowly. The body may be secreting more sebum and there may be a decrease in blood flow, giving the skin a faded appearance while fine lines appear to standout.
From 5 pm-9 pm, the skin is far more permeable to chemicals and other substances, and it responds more readily to topical skincare products.
From 9 pm-4 am, as with many other organs in the body, the skin begins to heal. The skin is at its most proliferative during the later and darker hours of the day, replacing old skin cells with new. During this time, the skin produces less sebum and is more acidic, with a slightly lower pH and increased histamine levels, resulting in dry, itchy skin that is prone to flare-ups (Sade, 2017; Matsui et al., 2016; Mehling and Fluhr, 2006).
Matsui, M., Pelle, E., Dong, K., & Pernodet, N. (2016). Biological Rhythms in the Skin. International Journal Of Molecular Sciences, 17(6), 801. doi: 10.3390/ijms17060801
Mehling, A., & Fluhr, J. (2006). Chronobiology: Biological Clocks and Rhythms of the Skin. Skin Pharmacology And Physiology, 19(4), 182-189. doi: 10.1159/000093113
Plikus, M., Van Spyk, E., Pham, K., Geyfman, M., Kumar, V., Takahashi, J., & Andersen, B. (2015). The Circadian Clock in Skin. Journal Of Biological Rhythms, 30(3), 163-182. doi: 10.1177/0748730414563537
Sade, D. The Aromatherapy Beauty guide (1st ed.). Toronto: Robert Rose.