This research was originally featured on Reviews.com – The Best Face Moisturizer
First, a lesson in how skin works.
There are three layers: the epidermis on the outside, the dermis in the middle, and the hypodermis underneath. Blood vessels deliver moisture to the dermis, which then travels up through the epidermis and evaporates. This is called transepidermal water loss (TEWL) and if there is too much TEWL going on, your skin will dry out.
Moisturizing is a misnomer. Water is the only thing that can hydrate skin. The job of moisturizers is to trap that water in, deliver water to the epidermis, or do a little of both.
Occlusives are the OG moisturizers: ingredients that are so thick and impenetrable water cannot pass through them. Petroleum jelly is incredibly successful at this, cutting TEWL upwards of 98%. The downside with wearing petroleum jelly on your face is that if feels like petroleum jelly on your face.
That’s where emollients comes in. They have a similar chemical structure as occlusives (long chains of carbon atoms) and work to block water from evaporating, but their technique is a little different.
The epidermis is constructed like a brick wall, with dead skin cells playing the bricks and fatty lipids and proteins playing the mortar. When temperatures drop, those proteins break down. Emollients penetrate the epidermis and fill in the holes those proteins leave, keeping TEWL under control. Bonus: Filling in those holes also makes your skin feel soft and smooth.
Humectants are the exact opposite. Hydroxyl groups in their chemical structure attract water, so as it soaks into the epidermis, the young, moist cells hanging out in the dermis travel towards the surface of the skin. (Humectants also stimulate the production of ceramides, waxy molecules in our skin that also reduce TEWL.)
First, a lesson in how skin works.
There are three layers: the epidermis on the outside, the dermis in the middle, and the hypodermis underneath. Blood vessels deliver moisture to the dermis, which then travels up through the epidermis and evaporates. This is called transepidermal water loss (TEWL) and if there is too much TEWL going on, your skin will dry out.
Moisturizing is a misnomer. Water is the only thing that can hydrate skin. The job of moisturizers is to trap that water in, deliver water to the epidermis, or do a little of both.
Occlusives are the OG moisturizers: ingredients that are so thick and impenetrable water cannot pass through them. Petroleum jelly is incredibly successful at this, cutting TEWL upwards of 98%. The downside with wearing petroleum jelly on your face is that if feels like petroleum jelly on your face.
That’s where emollients comes in. They have a similar chemical structure as occlusives (long chains of carbon atoms) and work to block water from evaporating, but their technique is a little different.
The epidermis is constructed like a brick wall, with dead skin cells playing the bricks and fatty lipids and proteins playing the mortar. When temperatures drop, those proteins break down. Emollients penetrate the epidermis and fill in the holes those proteins leave, keeping TEWL under control. Bonus: Filling in those holes also makes your skin feel soft and smooth.
Humectants are the exact opposite. Hydroxyl groups in their chemical structure attract water, so as it soaks into the epidermis, the young, moist cells hanging out in the dermis travel towards the surface of the skin. (Humectants also stimulate the production of ceramides, waxy molecules in our skin that also reduce TEWL.)
During the day, it’s important to wear a good sunscreen.
Experts prefer moisturizers with an SPF rating between 30 and 50, and broad spectrum protection. The sun protection factor (SPF) in moisturizers is what protects you from UVB rays. The number denotes how much longer it takes skin to sunburn than when unprotected: 30 times longer for SPF 30, 50 times longer for SPF 50, and so on. Don’t be fooled by the numbers, though. At their strongest, the difference in how much UVB radiation they block is around 1 percentage point, with SPF 30 blocking about 97 percent of UVB rays and SPF 50 blocking 98 percent. In fact, the FDA has proposed capping SPF at 50, arguing that any number higher is misleading to consumers who might believe there is such a thing as sunscreen that can block 100 percent of UVB rays. (There’s not.)
Broad spectrum sunscreen blocks both UVB rays — the kind that cause sunburns — and UVA rays, which penetrate the skin deeper and are closely linked to skin cancer. The real key to sunscreen, however, is coverage. Dr. Joshua Zeichner, an assistant professor in the dermatology department at Mt. Sinai Medical Center recommends a nickel-size dollop for a full face treatment along with regular reapplication.
Mineral sunscreens are the safest bet.
Sunscreens are divided into two categories: chemical and mineral. Mineral sunscreens are physical UV blockers — meaning they reflect UV rays so they can’t penetrate the skin — made from zinc oxide and/or titanium oxide. Chemical sunscreens absorb UV rays and then release that energy in a harmless way. There are a lot of chemical sunscreens, but six are used the most: oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate.
Both chemical and mineral versions work well, but we chose to cut chemical sunscreens because the risk for causing an allergic reaction or aggravating sensitive skin is heightened. Popular consumer watchdog group EWG says it’s riskier than that: It stresses that some chemical sunscreens can penetrate the skin and reach living tissue, causing hormone disruption.
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