1. Winter skin occurs in winter. Not exactly. “Winter skin” is characterized by dry flaky skin, itching and chapped lips. And more often than not, we can blame a dry climate. Surprisingly, the driest air is not always found in winter. A comfortable ambient humidity is about 40 percent to 60 percent. In Pittsburgh, Penn., the air is driest around April 20, and most humid in September. So in this type of climate, air can begin to dry out in the fall. However, in Las Vegas, Nev., the air is driest around June 23, with a relative humidity of only 10 percent! Our dynamic skin shrinks and expands relative to the environmental water content. In a dry environment, the stratum corneum loses moisture and shrinks, dries out and can even crack. 2So to prevent skin from drying out, check your forecast and adjust your indoor humidity with a humidifier (but do not crank it up all the way, or your subtropical microclimate will bring mites and mold).
2. Indoor heating is the cause behind winter skin. It is not so much the heat, as the amount of moisture in the air. Because warmer air (think warm and tropical) has the capacity to hold the most moisture, cold air naturally has a lower humidity – meaning that it carries little moisture. When this cold, dry air is brought inside and you crank up the heat, you are increasing the temperature but not the moisture. Even though you have the same levels of moisture inside as outside, it will be much drier in your home or office because now the warmer air can potentially hold more moisture, resulting in lower relative humidity and a faster water evaporation rate. Hello static hair and dry skin!
3. Drink more water. Drinking water to improve our complexion is one of the most pervasive myths regarding water intake out there. There is no science behind the claims that drinking eight glasses of water per day will flush out toxins and improve skin health.3 That is not to say you should not drink water – just do not believe the hype when it comes to hydrating the skin from the inside out. However, boosting your essential fatty acid intake could lead to improved lipid levels on the surface of the skin, so the bottom line is: drink plenty of fluids and hydrate skin with topical ingredients for best results.
4. You must apply a moisturizer immediately after showering. Maybe not. A study recently showed that people with atopic dermatitis (eczema) improved their skin hydration after using a moisturizer, regardless of when they did it (immediately after a shower, or 30 minutes later).4 And using emollients without bathing trumped all other regimens, including bathing and then moisturizing…but you may want to steer your clients into healthy cleansing habits! Short, lukewarm showers are best in the winter months. So it is not as important when you moisturize, as long as you do it.
5. Moisturizers can draw moisture from the air back to your skin. While some marketers would like this to be true, it is simply not possible unless you are in an environment with at least 80 percent humidity5 (read: sitting in a steam room). In fact, humectants (ingredients that bind water like glycerin, sorbitol, and urea) are inefficient in arid climates and can even cause skin dehydration.6 At low humidity, they pull moisture out of the dermis and epidermis to the surface where it evaporates into the atmosphere, worsening xerosis.5,6 A good practice to ease winter skin is to use humectants combined with emollients, and even occlusives in some instances. For longer-term use, look for products that combine humectants to promote water delivery to the skin surface, ceramides to reinforce the lipid barrier, along with natural moistering factor (NMF) components to help moisturize.7 Encourage your clients to layer serums, emollients and creams in the drier winter months.

References:
1. Relative humidity ranges. Retrieved from https://weatherspark.com/averages.
2. Stick, C., & Proksch, E. (2012). The influence of climate on the treatment of dry skin with moisturizer. Treatment of Dry Skin Syndrome p. 503-511. Springer Berlin Heidelberg.
3. Popkin, B. M., D'Anci, K. E., & Rosenberg, I. H. (2010). Water, hydration, and health. Nutrition reviews, 68(8), 439-458.
4. Chiang, C., & Eichenfield, L. F. (2009). Quantitative assessment of combination bathing and moisturizing regimens on skin hydration in atopic dermatitis. Pediatric dermatology, 26(3), 273-278.
5. Baumann, L. (2010). The Baumann Skin Typing System. Textbook of Aging Skin p. 929-944. Springer Berlin.
6. Kligman, A. (1999). Introduction to Dry Skin and Moisturizers: Chemistry and Function. (pp. 3-10) CRC Boca Raton.
Weber, T. M., et al. (2012). Treatment of xerosis with a topical formulation containing glyceryl glucoside, natural moisturizing factors, and ceramide. The Journal of clinical and aesthetic dermatology, 5(8), 29.