If it feels like your skin has been screaming lately, you're not alone.

Winter months in cold climates can be a recipe for dry, itchy, angry skin. "Xerosis," if you prefer the scientific term. 

But figuring out how to keep skin moisturized in the winter can be confusing. Should you change your diet? Drink more water? What about supplements and expensive oils? It's all mixed up in a web of pseudo-science and advice from people trying to sell you stuff.

We've narrowed this winter skin to-do list down to a few simple expert-approved tips.

Take a look at the advice, and then go give your skin some relief: 

Winter-dry skin isn't your fault. There's a vicious cycle at work.

It's a combination of dry winter air, and the skin that's right under your nose, your face, and your hands. Actually, it's covering the surface of your entire body.

The uppermost layers of your skin are called the stratum corneum, and they're kind of like your skin's shield, protecting what's inside, while keeping out bad elements from the environment.

Our so-called "shield" of armor, this stratum corneum, is made from about 10-15 micrometers of dead-cell skin. Scientific studies show these outermost layers play an important part in keeping natural moisture inside the skin.

But when the humidity drops, and winter chill creeps in, the outside air is drier. Then, making matters worse, we use radiators and heaters to stay warm inside, drying out those environments, too.

Our stratum corneum "shield" starts to dry out, opening up the skin's natural barrier.

David Leffell, author of "Total Skin: The Definitive Guide to Whole Skin Care For Life," and chief of dermatologic surgery at Yale School of Medicine, told Business Insider when the stratum corneum gets damaged, natural moisture "leaks out" of the top layers of our skin.

"That's when we start getting itchy, scratchable skin, making matters even worse," he said. And so, the vicious cycle begins. 

The most important thing you can do for your skin is moisturize it.

But remember, not all moisturizers are created equal.

There's one simple ingredient that you should look for on the back of your cream: lactic acid.

While sweet-smelling herbs and organic ingredients probably don't make much of a difference to your skin, there's one key addition that can help: lactic acid. Creams with lactic acid as one of the top ingredients will help you retain moisture. 

"They bind moisture, and they smooth the skin," Leffell says. 

Check for a label with an active ingredient of "lactic acid" or "ammonium lactate" (moisturizers like AmLactin and Lac Hydrin are good examples, but regardless of which brand you pick, the "lactic" or "lactate" ingredient should be one of the first, usually listed after water.) 

Soon, your skin will be as smooth as Cleopatra's.

Did Cleopatra really have amazing skin? I don't know, but scholars say it's rumored that she bathed in sour donkey milk.

Fermented dairy products like cheese and yogurt (and yes, sour milk), all have high levels of lactic acid in them. It's produced naturally when bacteria interacts with milk sugar, or lactose. There might not be enough of it in a milk bath to really do the trick for your skin, but modern moisturizers do an excellent job. 

Lactic acid is also used by dermatologists for chemical peels. 

"If you've been scratching a lot and the skin barrier is broken, it can sting at first when you put it on," Leffell says. "But it can be very effective." 

And do your skin another favor: don’t dilly-dally in the shower!

Keep the temperature of your winter showers warm, not hot.

When you step out of a hot shower, water evaporates quickly, taking with it some of the moisture on the surface of your skin.

That's why it's more important to keep showers short and to the point in the cold winter months than in the summer.

And applying moisturizer right after showering or bathing can help, because that traps in moisture. 

"It makes a big difference," Leffell says. 

Generally speaking, thicker creams are better than thinner lotions.

There are a few things to avoid, but the biggest one is alcohol.

Ethyl alcohol drys out the skin, so avoid rubbing it on your body.

There are some moisturizer ingredients like "cetyl alcohol" and lanolin. These fatty alcohols aren't like traditional drugstore alcohol, and the FDA says they're much better for your skin.

But wipes and makeup removers are sometimes made with the drying kind (which might just be called "alcohol" or "isopropyl alcohol" on the label) so watch out for it. 

If you're just dealing with problem spots like dry elbows, feet, and lips, old-fashioned petroleum jelly can help, too.

Products like Vaseline and Aquaphor can really help relieve persistently dry patches. 

But it’s such a sticky remedy, it's probably best to wait until the end of the day and slather on a bit before bedtime, or while relaxing at home.

Your palms and the bottoms of your feet are especially important zones to pay attention to, because they don't have the same kinds of "sebaceous glands" that lubricate the rest of our skin with a naturally-produced oily secretion called sebum.

And you can help your skin feel better by softening up your air, too. Perform this simple test to decide if a humidifier is right for you:

"You just have to... see if your skin is really dry when you wake up in the morning," Leffell says.

If you're noticing that, it's a sign a humidifier could probably help, because they replace the moisture in the environment that's sucked out by heating systems.

There are a lot of good reasons to eat healthy. But your skin probably isn't one of the most important.

"Whether it's avocados or salmon or omegas, they get digested and they don't selectively go to your skin," Leffell says.

The best way to deal with dry skin is to put something on it. So go ahead, get moisturizing. 

Business Insider

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