Week #4: Explore Your Moisturizer

I bet each of us uses moisturizer everyday, either for your face or body or both, especially during winter time. Do you know some of the main active ingredients in moisturizers, and how do they work once applied onto your skin?

INTRODUCTORY VIDEO

Standard YouTube license: How Does Moisturizer Work? uploaded by Reactions

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DISCUSSION 

TEWL is short for trans-epidermal water loss, a measurement of the amount of water passes from inside your body through the epidermal layer, or epidemis (the outer layer of your skin) to outside environment. This phenomenon occurs constantly with little control from us, and happens through diffusion or evaporation mechanisms. The mount of water loss is dependent on skin disruption, such as wounds, sun-burns, and outside factors such as humidity, temperature, and moisture¹. High amount of water loss causes your skin to be dry, and this is when moisturizer is needed, to keep the skin hydrated. Moisturizer can come in many forms, not just cream, like lotion, serum, and oil, though cream is the most common form².

Petroleum Jelly [Texture Zoom-In]

The most common occlusive agents include petroleum jelly, lanolin, zinc oxides, and silicones². Since occlusive agents' function is to block water from escaping, the texture of cream made up of these agents can be thick, such as the Vaseline Petroleum Jelly, making the skin greasy, oily, and thus are not preferable for oily and acne-prone skin. That's why I never use Vaseline Petroleum Jelly on my face, only my lips and chapped area on the body.

Glycol Stearate 

Examples of emollients mentioned are glycol stearate and castor oil, which makes skin soft by penetrating through it. Glycol stearate is an ester formed from a stearic acid (the right part) and ethylene glycol (the right part). Castor oil is a pale yellow oil extracted from castor seeds. Besides moisturizing, it can be used to treat skin infections, acne, warts, and stretchmarks³. The function of emollients and mechanisms in which they fill out gaps among corneocytes are clearly explained the video. One thing to notice is that emollients may not be effective and long-lasting².

Humectants enhance the production of ceramides. These are long-chained lipids that make up most of skin's outer layer and are important in retaining water for our skin. They are also barriers against bacteria and pollutants from outside environment. There are 9 ceramides associated with skin, labelled 1 to 9. Ceramides level, sadly, decreases as age increases, so that's why moisturizer is highly necessary for old people⁴.

Finally, one very interesting fact taken from Rio of XOVain (the second source, link is below) is that sometimes moisturizer can be claimed as anti-aging cream. However, if the ingredients list does not contain retinoids and alpha hydroxy-acids (aka AHA), the moisturizer does not help much with your wrinkles. With this, I may have a post about anti-wrinkle products in the future.

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Sources
Thumbnail background from Best Moisturizer
Petroleum Jelly from dwsworks
Chemical structures are from PubChem
¹ Chemistry of Skin: Trans-epidermal Water Loss (TEWL)
² Monday Beauty Vocab: Humectants + Emollients + Occlusive Agents = Moisturizer!
³ Castor Oil Health Benefits
⁴ SkinStore - Ceramides