冬季保湿护肤方法

How to combat seasonal dehydration and dryness.

How to combat seasonal dehydration and dryness

At RATIONALE, our evening Collections are built upon the three essential pillars of night-time skincare: strengthening the skin’s natural barrier function, recalibrating skin’s pH balance to a healthy acidic state, and enhancing overnight renewal by optimising the skin’s vital DNA repair processes. So, as winter approaches, we’re delving a little deeper into the first (and perhaps most underestimated) of these nightly processes: supplementing the skin’s lipid barrier to reduce the risk of seasonal dehydration and dryness.

A common misconception is that ‘dehydration’ and ‘dryness’ are interchangeable terms which describe the same conditions found in human skin. While they seem similar, these terms do differ…

Dehydration describes a lack of water in the skin, and requires hydration from water-soluble actives to both replenish and retain water. Dehydrated skin clogged by oil often remains dull, lacklustre in complexion and can feel uncomfortably tight.

Dryness, by contrast, means a lack of oil in the skin, and requires moisturisation from oil-soluble actives to replenish and bolster its delicate lipid membrane. Dry skin that is hydrated but not sufficiently moisturised will still flake, irritate easily and present with a rough texture.

Dehydration and dryness are not always mutually exclusive. It’s possible (and quite common) for both to present at once, and for both conditions to be exacerbated by incorrect skincare. While hydration is what makes our skin soft, it won’t remain hydrated if there is no physical lipid barrier protecting that hydration from evaporating and escaping the skin. Similarly, to topically nourish skin that is suffering from dehydration may smooth the surface but it will still lack vital hydration necessary for supple volume and elasticity.

So, let’s talk winter skin salvation. The plan for combating dehydration and dryness is a two-fold approach. 

Part one: Preventing Trans-Epidermal Water Loss

Trans-Epidermal Water Loss (TEWL) is the amount of water that passively evaporates through layers of the skin to the external environment. The average TEWL which occurs in human skin is approximately 300–400 ml per day, however, TEWL can be detrimentally accelerated by both genetic and epigenetic factors such as humidity, temperature (of either the weather or air conditioning – heating and cooling alike) and incorrect topical skincare actives which degrade the skin’s barrier rather than strengthen it.

Winter weather often sees an acceleration of TEWL in the skin, as we tend to spend more time indoors with artificial heating and, when we do go outside, our skin is shocked by drastic drops in temperature.

The solution: boosting skin resilience + hydration supplementation

The RATIONALE Resilience Collection (#1 The Serum, #1 The Crème, #1 The Mask) provides the skin with vital B-Group Vitamin support, acting as a booster shot for skin resilience and preventing TEWL as it helps to retain hydration in the Stratum Corneum (the skin’s outermost layer). 

Part two: Restoring the Protective Lipid Barrier Function

Our skin’s sebaceous activity naturally declines as we age, resulting in an increase of xerosis (dryness) which is particularly common in mature skin. However, younger skin is not invincible; TEWL poses a threat when damaging, astringent skincare formulations strip the skin of its natural lipid barrier (foaming cleansers and granular exfoliants being prime culprits). This often wreaks havoc by inducing breakouts, congestion and inflammation, where sebaceous glands are sent into overdrive in an effort to compensate for the lack of moisturisation. In fact, the skin’s barrier can actually take up to 72 hours to fully recuperate following this kind of damage.

The solution: lipid protection + ceramide production

The fourth facet of the RATIONALE Essential Six, The Integrity Collection provides the skin with the vital lipids it needs to defend against daily environmental damage and encourage night-time repair, including Vitamin E, Omega 3 + 6, Essential Fatty Acids and healthy Cholesterol. Ceramides are also an integral part of healthy skin barrier function. Partly water-soluble and partly oil-soluble, Ceramides encourage the skin’s own self-cleansing mechanisms and effectively bond to dirt, makeup, sunscreen and organic debris found on the skin. When emulsified with water, they form cleansing micelles which remove this unwanted matter, leaving skin smooth, soft and hydrated. With long-term use, this complete complement of Skin Identical Ceramides also encourages natural ceramide production in the skin.