How Does Moisturizer Work?

It’s the dead of winter. And… well, you know what that means: curling up with some hot cocoa, watching friends on Netflix and staring at your dry, cracked skin. Wait, what? [Reactions intro] When temperatures drop and heaters kick on, indoor air gets drier. That sends many of us scrambling for a moisturizer to ease the unsightly and irritating effects of dry skin. But what do these products actually do? As the name suggests, their job is to make your skin more moist. Skin dries out by a normal process with a fancy scientific name: transepidermal water loss. Or, if you like funny-sounding abbreviations, tewl. Blood vessels only supply moisture to the middle layer of skin, the dermis. From there, water moves outward through to the epidermis before it evaporates. A moisturizer’s job is to trap or replenish the moisture in the epidermal layer. Moisturizers come in three varieties: occlusives, emollients and humectants. Most products you buy have a combination of some or all of these. Occlusives are the old school moisturizers, and they work in the simplest way possible. They form a barrier over the skin that water can’t penetrate, stopping evaporation and keeping your skin moist. The best in the biz is petroleum jelly, sold as vaseline. It cuts tewl by 98 percent. The long carbon chains of the molecules that make up occlusives repulse water. The only problem? You don’t really want to walk
around covered in vaseline. We hope. More popular these days are the emollients. Instead of coating the skin, these are designed to penetrate, making skin feel softer and more flexible. They are made from similar chemicals as occlusives: molecules with long fatty carbon chains like stearates and castor oil. But they work differently. The outermost layer of your skin has a ‘brick-and-mortar’ structure where the bricks are dead cells, called corneocytes, and the mortar is made of fatty layers of lipids. Corneocytes are linked by proteins that form a strong barrier between your body and the bacteria, microbes and toxins in the outside world. The ‘brick-and-mortar’ stacks are thicker in places like your palms, but thinner on softer skin like your face. When the moisture level in the air goes down, the protein links break apart and fractures develop between groups of corneocytes. Emollients get beneath the skin’s surface and fill in these gaps, keeping tewl under control and helping your skin feel smooth. The third kind of moisturizers are humectants. Broadly, these molecules help attract and retain moisture in the epidermis. Humectants help get the younger, moist cells towards the outer layer of skin, as well as reduce the flakiness of dry skin. Humectants also stimulate the body’s natural production of ceramides, waxy molecules that reduce tewl. So don’t leave your skin out to dry this winter. Grab some lotion and stay hydrated. Your corneocytes will thank you. Enjoy what you saw? We’ll lik, share and subscribe. And while you’re here, be sure to check out our other videos like, “is it ok to pee in the
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47 Replies to “How Does Moisturizer Work?”

  1. I've been wondering about this for awhile! My skin has been really out of control this winter! Thanks for the knowledge!!

  2. "How does moisturizer work?"  I thought we covered this in a Cosmetology program I went through over 20 years ago, but clearly we did not.  lol

  3. Winter… oh…. yeah… I totally forgot the planet is a half sphere called north where all the youtube users (and the interwebs in general) live.

    I'm sorry if that sounds too rant-ish, but I'm getting rather fed up with most youtube channels' attitude towards seasonal stuff. Many good ones (including, of ourse yours) normally tend to be all progressive and politically correct, make effort towards inclusive language, the defense of minorities and forgotten cultures and all hat stuff… and then they go on ingnoring that half of the planet doesn't necesarily think that filling the tube with winter topics just because you are cold makes that much sense. I don't want to seem like the tipical butthurt internet troll, and I certainly apreciate your excelent channel, but is it so much extra effort to say that it's winter in the northern hemisphere and push the north-centric language a little further away. It's just a silly little simbolic thing, but if more channels would do it, many people in the global north would maybe start thinking their inmediate reality isn't the only one.

    By the way, I love your channel, so keep up the good work (and always improve). Sorry if I sounded a bit harsh.

  4. What a great and informative video! As dermatologists, we appreciate the science behind the products we recommend to our patients! 

  5. I have 2, Clean & Clear Dual Action Moisturizer and Cetaphil Fragrance Free Daily Facial Moisturizer. What types are they based on this video?

  6. Natural ingredients like coconut oil, cocoa butter, etc- what category would such moisturizers fall under? Any and all help is appreciated!

  7. I'm just thinking the first kind of moisturizer is vaseline, the second is the regular body lotion (like nivea, johnson baby lotion… ) and the third is body butter (like shea or mango butters and carrier oils mixtures)… I wonder if my thoughts r correct ?

  8. So most white people be ashy too but you can’t see it. Don’t it feel irritating to have dry skins. It’s makes me cringe.

  9. I’m a Mexican-white guy that never used to lotion until I came across a Bill Burr stand up where he talks about that subject

  10. Here's a really good product used for the care of nails, hair, scalp and combination skin, it is easily absorbed and rich in plant collagen to keep the skin moisturized and supple. Helps to prevent stretch marks. –

  11. I bumped into Keanu reeves in 1999 in London I said what's your secret for staying young he said mouisturiser. I laughed I didn't believe him I thought it was a girl thing. Seen him on a talk show the other day. Sh1t I should have started 20 years ago lol.

  12. During the winter my hands get so dry the skin CRACKS. I know I'm alone…I'm happy this video exists, thank you for satiating my curiosity. Subbed.

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