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Every time we use our skincare, we usually follow faithfully the instruction on the packaging on how to apply it. Surprisingly, sometimes the same type of products may have different instructions on usage. Some have indications to pat the product, spread all over the skin or even rub it gently. There are even special tools claiming to improve product ability. Will be there a difference in how the product works?
As far as the effectiveness of a topical product like skincare, we need to understand our skin first. Our skin consists of 3 layers, which are the epidermis, dermis, and hypodermis. The epidermis itself is the outer layer consisting mostly of keratinocytes, which is the main cell of the skin. The epidermis is a thick part consisting of 4 layers which are (from outer to inner part) stratum corneum (SC), stratum granulosum (SG), stratum spinosum (SS) and stratum basal (SB).
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When we apply skincare to our skin, it will first reach the SC layer. SC consists mostly of dead skin layer (keratinocytes), converted into a wall-like structure with the outermost stratum composed by proteins and lipids with the ability to form a barrier preventing unwanted substance to enter and water loss (transepidermal water loss or TEWL).1 This formation will act as a barrier able to prevent and limit the penetration of the active ingredients applied topically on our skin. Here, the skin biochemical barrier function will play a part in determining which active ingredients can penetrate deeper. After the epidermis, the dermis level is the part where sit the blood vessels. Now, most skincare products easily sold on the market without the doctor’s prescription cannot penetrate until this part. They can only go up to the epidermis level or even only form a layer on top of the epidermis. What happens if the active ingredient able to reach the dermis level? There is a possibility they can enter our blood system.
What are the factors that could influence the penetration ability of the active? There are 4 main factors which are:
1. Duration of the exposure
2. Skin condition
4. Method of application
As a user, we can only play around in point 4, which is how we apply the product. You can alter the way you apply your skincare depending on the area. Cheeks and forehead can be treated using a gentle rubbing motion, whereas a delicate area like under the eye needs to be patted gently. When talking about the application method, a study done by Mercer University in the US in 2017 tested the distribution of an active (salicylic acid)on the skin surface of pig skin in different ways. The parameter they use is to test the distribution on the skin surface and skin integrity. When comparing different type of applications using a rubbing motion between vertical glass rod, rolling a horizontal glass rod over the skin, a metal-tipped robot, and a gloved finger, One of the most interesting results found in the amount of salicylic acid is higher in the SC, epidermis and even at the dermis when rubbed with a gloved finger.2 Hypothetically this may be because the gloved finger has the biggest surface area compared to other methods. Another interesting information concerned the different movement: vertical and horizontal rubbing using the same tool, vertical rubbing shows a significantly higher penetration into the skin compared to horizontal rubbing but in a longer time (more than 15 min).2 We cannot apply this to all actives because it depends on the characteristic of the active ingredients such as its tendency to solute in water solution and their molecular size.
Another thing to remember, even though there is a study showing that the harsher rubbing method by adding pressure or using a coarser surface to apply may enhance the penetration of the active this could cause disruption of the skin barrier. The skin barrier will lose its protective function allowing unwanted impurities to penetrate our skin, therefore, causing acne or even a bacterial infection. Patting motion can also be used as this technique is gentler because it doesn’t tug or pull at your skin, therefore, protecting your skin barrier condition.
So next time you wanted to apply your skincare, remember that different part of your skin needs to be treated differently. For delicate part, patting motion is suggested whereas on other parts, gentle rubbing using your finger is enough.
(1) Stumpp, O., Chen, B., & Welch, A. J. (2006). Using sandpaper for noninvasive transepidermal optical skin clearing agent delivery. Journal of biomedical optics, 11(4), 041118.
(2) Nguyen, H. X., Puri, A., & Banga, A. K. (2017). Methods to simulate rubbing of topical formulation for in vitro skin permeation studies. International journal of pharmaceutics, 519(1-2), 22-33.
(3) Decker, A., & Graber, E. M. (2012). Over-the-counter acne treatments: a review. The Journal of clinical and aesthetic dermatology, 5(5), 32.
https://www.brit.co/skincare-product-application-pat-versus-rub/ (accessed on 26th March 2020)
https://www.marieclaire.com/beauty/news/a23093/rubbing-vs-pressing-skincare-method/ (accessed on 26th March 2020)
https://www.allure.com/story/patting-japanese-skin-care-technique (accessed on 26th March 2020)