Ep 15: Winter Skincare + Haircare Tips

Now that we’re in the month of December, it’s COLD outside in the Northern Hemisphere. As I was doing the research for this episode, the first blizzard of the season hit, further proving my point. With the cold comes a lot of changes in the environment; temperatures get colder, brisk winds are more frequent, humidity drops, and our heaters kick on. These environmental changes can, in turn, cause a lot of changes to our skin and hair. So for this episode, we’re going to chat about why our skin & hair changes with the seasons, and what you can do to combat these issues to keep healthy skin and hair all year round. 

How the environment and your routines change in the winter

• Less humidity (water) in the air. There are two different measurements of humidity, absolute humidity and relative humidity. Absolute humidity is the actual amount of water in the air, regardless of the temperature outside. Relative humidity, however, is how much water is in the air relative to temperature. Cold air can’t hold as much water vapor as warm air can, so when the weather gets cold, the relative humidity is higher. You can kind of think of it like a water tank; warm air has a bigger tank than cold air, so if there is the same amount of moisture in the air, it’s going to fill up the cold tank faster because it’s smaller. 

• When you heat the cold air inside (a la heaters), the relative humidity drops because you’ve made the tank bigger without increasing how much water is in the air. If you don’t add more water to the air through something like a humidifier or plants, everything is going to feel more dry; skin, lips, throat and hair. 

• Cold, dry winds are more common. Wind increases your heat loss (you lose heat faster) and it also strips the thin layer of humid air right next to your skin, which speeds up water loss. That’s why “windchill” exists and why your face gets wrecked on cold, windy days even if the temperature number doesn’t look that bad.

• UV-B radiation drops because the sun is lower in the sky and the days are shorter than in the summer. However, UV-A is still the same year-round, so it can contribute to wrinkles and pigment. Also, snow can reflect UV, so if it’s snowy outside you can still get a lot of UV on your exposed skin; this is why it’s common to get sunburnt while you’re in the snow, even if it’s cold outside. 

• All of these changes can contribute to water loss in the skin, more irritation and aggravating skin issues like eczema, redness, flares, and tightness. 

• It’s common for people to wear more layers, and warmer clothing like wool and synthetics. This increases friction, both with your skin and hair, and can lead to irritation. Hats and scarves also create a lot of friction with your hair and can lead to frizzy, staticky, dry or broken hair. 

So how exactly does your skin and hair change in the winter?

How skin changes in the winter

The skin has three main layers: Epidermis, dermis, and hypodermis. These layers are made from water, protein, fats and minerals. On the outermost layer of your skin, we have what’s called the stratum corneum; this is more commonly known as your skin barrier. This barrier is made up of dead cells, called corneocytes, with lipids. Think of it like a brick wall; the corneocytes are like bricks, and the lipids like the cement in between the bricks. The corneocytes have keratin and natural moisturizing factor (NMF) which loves water; they soak up water and hold onto it like tiny sponges. The lipid matrix (aka the cement) fills the small spaces between the corneocytes, and this is what slows down water movement and keeps irritants out. It does this because lipids are very hydrophobic (they dislike water) so they can repel it and keep it inside your body, instead of letting it evaporate out. 

Unlike a real brick wall, however, the skin barrier is semi-permeable, which means it does let some things in and out. The deeper layers of your skin are full of water, and there is always a gradient; it’s wetter inside your skin and drier outside. Remember a few episodes ago how we talked about osmosis? It’s the same idea here. So water naturally moves from the wetter layers of your skin and outside to the surface, where it evaporates. This is known as trans-epidermal water loss, or TEWL; it’s how much water leaks out through the outer layer of your skin, and we use it as a way to see how strong or weak your skin barrier is.

If you’re like me, you might be asking yourself “okay, so the main purpose of the skin barrier is to not allow water in or out. If that’s the case, how are topical moisturizers even effective? How do the moisturizing ingredients get into your skin?” WELL, like I said, it’s semi-permeable which means some water can get in. But also, we use cleansers with surfactants (which are doing the cleansing) because they stick to dirt/oils/impurities and remove them from the face. BUT, they also temporarily disrupt the lipid layer, and this allows moisturizing ingredients to get in. So it’s most effective to cleanse your face and then put moisturizer on right after, because the ingredients in the moisturizer can actually get into your skin layers since they’ve been temporarily disrupted by the cleanser. 

Also, most of the long-term hydration in your stratum corneum comes from water inside your body, diffusing up from the dermis, rather than the products you put on top or from the air. Topical water can hydrate your skin briefly, but if you don’t seal it in, it just evaporates, and it can sometimes even leave your skin drier than it was before. 

There are a lot of things that can disrupt your skin barrier, and this happens by stripping or disrupting the lipid layer. A lot of those things happen to also become more common in the winter; heat, friction, harsh cleansers, a lack of moisture, etc. 

According to a 2022 study, there are a lot of discrepancies in the studies that have been done regarding how the seasons and climate affects TEWL. There’s further research that can be done on how the environment affects your skin in the winter, but this is what we have so far. 

Adjusting your routine for winter

There are several things you can do to adjust your routine to be more effective in the winter. The biggest focus is maintaining water in your skin so you can have a healthy skin barrier, and there are a lot of ways to do that. 

• Swap to a more heavy-duty moisturizer. Make sure what you’re using has the big three: humectants, emollients and occlusives. We’ve talked about these before, but as a refresher:

  • Humectants hold the water inside the corneocytes (or the “bricks”). Ingredients like Glycerin, Urea, Hyaluronic Acid and Sorbitol bind water in the corneocytes and upper stratum corneum, which can increase the water content in your skin. They can also grab water from the deeper layers of your skin, in addition to the water in products you’ve just applied. 

  • Emollients smooth the surface of your skin and can help fill in the gaps in the lipid layer (aka the cement between the bricks). These are ingredients like oils, esters, ceramides, cholesterol, and fatty alcohols. By filling the gaps in your skin layers, it can improve the integrity of the barrier and also make your skin feel smoother. 

  • Occlusives are ingredients that form a film over your skin and slow down the evaporation of water. This includes ingredients like petrolatum, mineral oil, dimethicone, and waxes. These ingredients repel water, so they can trap the water inside the skin, reducing TEWL and allowing your skin to maintain more hydration. 

• Avoid harsh cleansers. You may want to consider using a gentler cleanser with a creamy/milky texture to avoid stripping your skin of too much moisture. 

• Add an occlusive product as the last step in your routine. This can be anything that forms a film over your skin; my favorite is good old Vaseline or Aquaphor, but there are other products on the market that can also work for this. Do this as the last step in your routine to seal in moisture and slow down the TEWL.  

• Consider doing your nighttime routine 1-2 hours before bed, rather than right before. This gives the product time to soak into your skin instead of ending up on your pillow. I think this is useful for any time of the year, but it’s especially important in the winter. 

• Start using a humidifier in your room at nighttime - this will add more humidity to the air and can decrease dryness and improve hydration. This isn’t just helpful for your skin, but also for your overall body as well. 

• Drink more water!!! Like I mentioned earlier, most of the hydration in your skin comes from inside your body, so make sure you are drinking a LOT of water so your skin has plenty of inner water to pull from. 

Now that we’ve discussed our skincare routine, let’s move onto our hair. 

How hair changes in the winter

First and foremost, it’s important for you to know that your hair is different from your skin because it’s dead. The root of your hair is attached to your skin and that’s alive, but once it starts growing past the bulb, it’s no longer living. This means your hair is quite different from your skin in terms of how to care for it.

Structurally, hair is made out of keratin. It has three main components of structure; the cuticle layer, the cortex, and sometimes a medulla. The cuticle layer is the outermost layer and is made up of overlapping “shingles” that make the surface hydrophobic (water-hating) and low friction. Porosity, a term you may have heard of before, refers to how raised or flat these cuticles are. Low porosity hair has cuticles that are very flat to the hair strand, while high porosity has cuticles that are lifted (and sometimes even missing altogether). The cortex is the inner layer of your hair, and it makes up around 90% of your hair’s structure. This is where the keratin proteins and bonds live; it also holds the most water and gives your hair strength and elasticity. Some people also have a medulla - not much is known about the medulla or how it impacts the hair, but from what we know it’s basically a protein/water pocket that sometimes runs through the center of your hair. 

Humidity can impact your hair a LOT. If you’ve styled your hair at high humidity, it’s actually better to stay at that same humidity than to go to a less humid location. And if you style your hair at low humidity, an increase in humidity will also mess up your hair.

Does hair actually need water?

This is a topic that I am still trying to understand, honestly, because there just isn’t a lot of good research on it, and I feel like every expert says something different. I was taught that your hair needs water, but over time I’ve heard a lot of experts say that hydration is actually bad for your hair. Right now, I believe that the truth is somewhere in the middle. 

First, we need to note that “hydration” and “moisturization” aren’t technically the same thing. Hydration is the process of actually increasing the water content, while moisturization is locking in that water and preventing water loss. So humectants hydrate, while emollients and occlusives moisturize. 

Water and “hydration” aren’t simply good or bad for hair, they just change how hair behaves. Like we mentioned in the Reddit Reacts: Haircare episode, hair is made of proteins held together by permanent and temporary bonds; water breaks the temporary ones, which makes wet hair softer, stretchier, and easier to reshape, but also weaker and easier to snap. There’s also a “sweet spot” for how much water hair should hold: too much water and the fiber swells unevenly and feels rough and frizzy, too little and it becomes stiff, brittle, and staticky (like on planes or in heated rooms in winter). Most “hydrating” products aren’t stuffing water into the fibre; they’re conditioning the surface and coating it with ingredients like silicones, oils, and fatty alcohols that smooth the cuticle, reduce friction, and replace the thin natural oily layer that gets stripped off with damage. So the real goal isn’t “maximum hydration,” it’s controlling how much water is in your hair, plus good conditioning products and treating it gently. 

Adjusting your haircare routine in the winter

• Amp up the moisturizing/conditioning products in your routine. Conditioning ingredients like silicones and cationic conditioners are the most important, but “hydrating” products can also be beneficial too. This is because when hair builds up static, the strands push away from each other and you see flyaways. Many hair products help cut down this charge, and hair that has more moisture is usually less staticky as well, because the extra water makes the fibre more conductive, allowing the charge to spread out instead of piling up in one spot. So products that have both humectants and conditioning ingredients are usually the most beneficial (but I would say that conditioning ingredients should be your top priority). 

• Be generous with the amount of conditioner and leave-in products you’re using. If you notice your hair is getting frizzy/dry more quickly, you can either use refresh products between wash days, or just amp up your wash schedule. Yes, you’re getting your hair wet more often which isn’t the most ideal, but it will also allow you to condition it more, too. Just be sure to handle your hair carefully when it’s wet. 

• Consider pre-washing more often. This is the practice of applying an oil or silicone-based product to your hair before washing it; it helps with coating the hair shaft and preventing water from leaving the hair strand. My favorite pre-wash oil is the 

• Adjust for the amount of humidity in the air. If you’re planning on spending the whole day outside, maybe add more conditioning products or a hair oil to your hair before you do. Just be aware of how to adjust your routine to the conditions outside.

• Be so SO careful with scarves, hats and coats. Try to wear your hair up when you’re wearing heavy coats or scarves, if you can. If not, just limit how often you wear them if possible, and also consider applying a hair oil to help decrease friction. Friction between your hair and the fabrics can wreck your hair, so take precautions! 

Conclusion

So to wrap this up, winter isn’t out to personally ruin your life… but it is working against your skin and hair a little. The air outside is colder and drier, the air inside gets even drier once we heat it, wind is stripping away that thin humid layer right next to your skin, and UV is still very much happening (rude). All of that adds up to more water escaping from your skin and hair, more irritation, more flares, more frizz, and more static. But none of this means you’re doomed; it just means your summer routine doesn’t automatically work for winter routine. 

The goal in winter is pretty simple: protect your barrier and control water loss. For skin, that looks like gentler cleansing, heavier moisturizers with humectants + emollients + occlusives, sealing things in at night, running a humidifier, and actually drinking water to stay hydrated and hot. For hair, it’s beefing up your conditioners and leave-ins, using products that cut down on static and friction, being extra gentle when it’s wet, protecting it from rough fabrics, and tweaking your routine based on how dry or humid it is that day. Winter is always going to change your environment, but once you understand the “why” behind those changes, you can adjust your routine so your skin and hair stay as calm and functional as possible, instead of being your worst enemy until spring.

Bibliography

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4. “Skin: Layers, Structure and Function.” Cleveland Clinic, 13 Oct. 2021, my.clevelandclinic.org/health/body/10978-skin. 

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8. Wong, Michelle. “Hair Frizz Science: Water and Hydrogen Bonds.” Lab Muffin Beauty Science, 29 Nov. 2019, labmuffin.com/hair-frizz-science-water-hydrogen-bonds/.

9. Wong, Michelle. “Is Hydration Destroying Your Hair? The REAL Science.” Lab Muffin Beauty Science, YouTube, 18 Nov. 2024, www.youtube.com/watch?v=khNaXP11zc8. 

10. “Hydrating vs Moisturizing: A Guide to Healthy Skin.” Aveeno, www.aveeno.com/journal/hydrating-vs-moisturizing-what-know-healthy-happy-skin.