Are any of you wondering why it seems like your moisturizer isn’t working as well as it used to? You’re not alone. Every year around this time people come to me complaining that their moisturizer just doesn’t seem to be as powerful as it used to be. “Aha!,” I’ve exclaimed, in the nicest way possible of course, “It is not your moisturizer! It’s just winter.” It’s true that people experience increased dry skin in the winter. But this year I decided to do a little more digging to find out exactly why. As it turns out, there is startlingly little scientifically sound explanation to be found, and myths abound.  As is often the case, it falls to us to sift through the nonsense and make some sense of this issue.

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First, let’s dispell the myths:

When weather gets cold, it gets dry. This is claimed so often and by so many “reputable sources” that I almost took it at face value myself. But when I decided to double check this pervasive claim, it completely fell apart. I looked at historical charts of humidity levels across the United States throughout the seasons.* It turns out that humidity levels show no particular trend from summer to winter. In fact, in many cities, even Northern cities, humidity levels are higher in the freeze of winter than in the bask of summer.

The winter is blustery and wind dries out the skin. Many of us can recall experiencing our share of cold, windy winter days, and could swear that we experience “windburn”, characterized by dryness, redness, and irritation after being outside on these blustery days. But a look at the evidence forces us to consider other possible causes. The only experiment I could find was performed all the way back to 1937, and was published in Popular Science. Scientists founds through using a wind tunnel that wind alone does not create “reddening or chapping” of the skin. Furthermore, upon browsing through historical wind speed charts, I found that that much like humidity levels, wind speeds show no yearly trend. There is no evidence of higher winds in the winter months. Regardless of all this evidence against the wind creating redness, dryness, and irritation, many sources not only talk about the existence of windburn, but will even explain why it occurs. The most widely used explanation is that wind removes surface lipids (oils) from the skin. Exactly how the wind performs this feat is conspicuously absent from all of these articles. Furthermore, if wind is just as strong in the summer, why don’t people seem to experience windburn as much in the summer? Another common explanation that attempts to explain windburn, which is the current explanation on Wikipedia, is that windburn is actually just sunburn caused by the wind removing surface lipids (oils) which help protect us from UV rays (another claim I am yet to find evidence to support). While the wind can remove some of these surface lipids year round, they say, the removal of the surface lipids in the winter coincides with a season when we do not protect our skin as valiantly from the sun. Thus the redness and irritation people experience is simply a sunburn. This explanation is incomplete at best, and completely misinformed at worst. Yet another explanation, albeit less frequently posited, claims that wind removes sweat, which normally helps filter UV rays. Again, how sweat helps filter UV rays is conspicuously absent.

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Whew. So, now that we have gone through the myths, the fact remains that many people experience dryer skin in the winter. Why? After looking at all of the available evidence, I have a hunch it can be attributed almost entirely to:

Artificial heat: Mother nature can heat up or cool down the great outdoors while keeping humidity levels steady, but when we heat indoor areas, this lowers humidity. When you look at the science of relative humidity (I won’t bore you), this is how it works. For an everyday example, notice how when you heat your bathroom while taking a shower there is less steam in the air. Since most of us live and work in artificially heated indoor environments in the winter, it’s likely we experience long-term exposure to lower humidity environments during the winter months. This dries out the skin, causing many of us to wonder why our moisturizer isn’t working as well as it used to. Back to my original point, “It’s not your moisturizer!” And introducing my new, improved answer, “You’re living in lower humidity indoor environments in the winter!”

And what about the cold? Strangely, none of the authors or reporters writing about winter and dry skin mention the effect cold air itself has on the skin. However, I have a hunch extreme temperatures may figure into a complete explanation of why some people experience dry skin in the winter. When we expose our skin to freezing temperatures, the skin reacts through natural protective methods, most prominently by withdrawing blood from the surface of the skin to protect core temperature. This is the first step which ultimately leads to the skin freezing which causes frost bite and cell death. My hunch is that perhaps even during shorter duration exposure to freezing temperatures which people sometimes experience on cold days, the skin still reacts through a more mild form of cell death. This mild cell death, while not as apparent as the blisters caused by frostbite, is evidenced by flakiness or dryness as the dead cells flake off. The redness experienced by many people after exposure to winter weather, while it would require further research for me to be more definitive, could be the result of cell death or simply the body returning blood to areas where it has been withdrawn.

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So, what can we do about it?

1.  Humidify your home/workplace. Install a humidifying system into your central heat. Alternately, if you use wood burning stoves or kerosene heaters, you can place pots of water on top and let the water evaporate, then repeat. You can always boil a large pot of  water on the stovetop as well, being careful to keep a close eye on it of course. There are commercially available electric stand-alone humidifiers as well. 60% humidity is a good general goal to shoot for. You can measure humidity with widely available humidity measuring devices which are available at most hardware stores, or you can be more relaxed about it and just notice how you–and your skin–feel. When the humidity reaches a comfortable level you will feel less dry and generally more comfortable. You should also notice less static electricity, less shocks, and less frizz to your hair. An easy way to tell if you’ve gone too far and over-humidified your space is if your windows start to pool water at their bases.

Perk: Adequately humidified air feels warmer than dry air at the same temperature. In other words, you can get away with heating to a lower temperature.

2.  Use more moisturizer: An extra pump or two of moisturizer each time you apply should help.

3.  Add jojoba oil: Since jojoba oil does not evaporate, 5-6 drops of jojoba oil added into your moisturizer each time you apply it will provide a boost of all-day moisture support.

*Yes, I know. There is more to the world than the United States, but…well, okay fine, I have no excuse. I’ll make a note to look outside the U.S. for my next research-related blog.