Seasonal routine for mature dry skin: climatic impact on the barrier, TEWL and season-by-season adjustments

Skin Barrier and Climate: Understanding Environmental Impact on Mature Dry Skin

Mature dry skin is subject to a dual phenomenon of weakening: on the one hand, natural aging reduces the amount of sebum, hyaluronic acid, and natural moisturizing factors (NMF), and on the other hand, seasonal climatic variations stress an already fragile skin barrier. To understand how to adapt your routine throughout the seasons, it's helpful to know the principles at play in the stratum corneum — this superficial layer of the epidermis that constitutes your first defense against the outside world.

The stratum corneum is a lamellar structure composed of corneocytes embedded in a lipid matrix organized into bilayers (ceramides, free fatty acids, cholesterol). This "brick and mortar" architecture fulfills two opposing but complementary functions: retaining water in the deeper layers of the epidermis and limiting the passage of external agents. The key measure of this barrier function is transepidermal water loss (TEWL), expressed in g/m²/h. In comfortable skin, TEWL generally remains low at rest. In mature dry skin, this threshold can be higher, signaling a less effective lipid barrier.

It is precisely on this already fragile TEWL that seasonal changes exert their most marked effects — with distinct phenomena depending on the season, which call for specific routine adjustments. Explore all our articles on mature dry skin →

Winter: Cold Air and Low Relative Humidity — the Silent Enemy of TEWL

Winter represents the most challenging season for mature dry skin, for a simple physical reason: cold air has an intrinsically low water retention capacity. When the outside temperature drops below 5°C, the ambient air's relative humidity can fall to less than 30% — sometimes as low as 15–20% in heated interiors with central heating. This extremely low humidity creates an unfavorable gradient between the skin surface and the environment.

Concretely, this water vapor pressure differential favors an increase in TEWL that can reach +40% compared to neutral conditions (relative humidity of 50–60%). For mature dry skin, whose basal TEWL is already high, this excess moisture loss results in rapid skin dehydration: tightness in the morning, visible flaking on the cheekbones, accentuation of expression lines due to dehydration, and even the appearance of micro-cracks on the thinnest areas (eye contour, labial commissures).

Cold also exacerbates the situation by slowing down the natural renewal of the skin surface and constricting superficial vessels, reducing supply to the epidermal layers. The amount of ceramides — fundamental lipid molecules of the intercellular "mortar" — decreases under the effect of cold, further weakening the barrier's appearance.

The winter strategy for mature dry skin relies on three pillars: occlusion (reducing TEWL with a protective film), active rehydration (providing humectants that capture residual atmospheric water), and lipid supply (supplementing depleted ceramide bilayers). Prickly pear seed oil, rich in linoleic acid (omega-6, 55–65%), plays a valuable sensory role here: linoleic acid is a naturally appreciated component in dry skin care, and its topical application helps maintain skin comfort and suppleness, making it a sought-after ally compared to oleic-dominant oils for dry skin comfort.

Summer: Heat, Vasodilation, and NMF — When Dry Skin Transforms

Paradoxically, summer does not protect mature dry skin from aggressions. While higher relative humidity (often 50–70% in temperate Europe) reduces physical TEWL, heat triggers reactions that alter the skin's appearance.

Summer vasodilation increases cutaneous blood flow — which is beneficial for the complexion but is accompanied by increased sweating. Sweat, secreted by eccrine glands, modifies the skin's natural moisturizing factor (NMF). NMF is a set of hygroscopic molecules (pyrrolidone carboxylic acid, lactic acid, urea, free amino acids) naturally present in corneocytes, which contribute to their ability to retain water. During intense sweating, some of these water-soluble molecules are "washed away" from the skin surface, temporarily reducing the intrinsic moisturizing capacity of the stratum corneum.

For mature dry skin, whose NMF is naturally depleted with age, this summer leaching can paradoxically accentuate the sensation of dryness despite a humid environment. Added to this is the effect of UV radiation which stresses surface lipids — a phenomenon particularly marked after 40–45 years when the skin's natural mechanisms are slowed down.

In summer, the routine should shift towards lighter textures that do not saturate an already vasodilated skin, while maintaining the presence of antioxidant active ingredients. This is where a natural vitamin C serum comes into its own: an antioxidant that helps protect against external aggressions, it helps unify the appearance of the summer complexion and preserve the firm and plump appearance that UV and heat tend to alter. See our natural radiance serum guide →

Wind and Mechanical Abrasion: The Invisible Aggression on the Stratum Corneum

Wind is perhaps the most overlooked daily climatic aggression. Its action on the stratum corneum is directly mechanical and abrasive: microscopic particles carried by the wind (dust, pollutants, pollen) strike the skin surface at speeds that can reach several meters per second, causing forced micro-desquamation of surface corneocytes.

For mature dry skin, whose surface renewal is already slowed down (from 28 days to 45–60 days after age 50), this accelerated loss of superficial corneocytes weakens the compact layer that ensures the barrier's impermeability. The result: skin that "peels" slightly, areas of temporary redness, increased roughness, and paradoxical sensitization — while mature dry skin is generally not very reactive, it can develop temporary reactivity to strong winds, especially in the mountains or by the sea.

Wind also accelerates water evaporation on the surface, amplifying TEWL synergistically with cold and low humidity. In conditions of simultaneous cold and dry wind — typical of winter or spring days at altitude — TEWL can be multiplied by 2 to 2.5 compared to calm conditions at the same temperature.

Mechanical protection against wind involves applying a light film-forming formula as a barrier (shea butter low concentration, ceramides, squalane) and wearing a thin scarf to protect the most exposed areas. After exposure to wind, a rich treatment applied in the evening helps comfort the skin and reconstitute the appearance of the intercellular cement. Discover radiance and comfort treatments →

Seasonal Adjustment Protocol: Your Vitamin C Serum Throughout the Months

Vitamin C serum is not a product to be used invariably throughout the year. For mature dry skin, its application protocol must adapt to seasonal climatic variations to optimize its effects on radiance, complexion uniformity, and antioxidant protection.

Autumn — Transition Phase (September-November): This is the ideal period to (re)introduce or intensify vitamin C serum. Skin, fatigued by summer UV, shows resurfacing spots, irregular texture, and loss of uniformity. Daily morning application, on slightly damp skin after gentle cleansing, helps revive radiance and unify complexion appearance, and prepares the skin for winter. Combine with prickly pear seed oil as an evening oil serum to enhance lipid comfort before the first major cold snaps.

Winter — Intensive Phase (December-February): Continue with vitamin C serum in the morning but imperatively layer a rich cream (high ceramide/linoleic acid ratio) to counteract increased TEWL. Vitamin C acts synergistically with vitamin E, two antioxidants that help protect against external aggressions related to cold and repeated indoor/outdoor thermal variations. Avoid applying the serum to skin with micro-cracks (risk of tingling) — wait until these areas have regained comfort before resuming. An indoor humidifier is recommended to maintain humidity above 40%.

Spring — Reboost Phase (March-May): Gradually lighten layering textures while maintaining vitamin C serum. Spring temperature variations (large day/night difference) stress the barrier differently — prefer a "serum + light fluid" approach in the morning rather than serum + rich cream. Introduce a minimum SPF 30 because UV radiation increases rapidly, and less accustomed skin is more susceptible to photoinduced damage.

Summer — Antioxidant and Lightness Phase (June-August): In summer, vitamin C serum becomes a protective rather than corrective active ingredient. Its main role is to help neutralize free radicals generated by UV before they alter surface lipids and complexion uniformity. Always apply before SPF — the two active ingredients potentiate each other. Store the serum in the refrigerator to avoid accelerated oxidation by heat, a visible sign when the tint changes from slightly yellow to orange-brown. All our radiance and uniformity resources →

Vitamin C retains its place all year round, but not at the same concentration. In summer, when exposure is high, it makes perfect sense to use it in the morning under sunscreen. In winter, a lower concentration is sufficient, and the time saved goes to the nourishing phase.

It is the only active ingredient in a beauty routine that deserves to be maintained without interruption. More demanding anti-aging treatments can be alternated according to the season; the morning antioxidant, no — caring for mature dry skin requires this continuity.

Mistakes to Avoid in the Mature Dry Skin Seasonal Routine

1. Using the same cream all year round: This is the most common mistake. A light cream suitable for mild September becomes insufficient in January when TEWL increases by 40%. Conversely, a rich winter cream applied in July to vasodilated skin saturates the pores and can lead to milia or reactive breakouts. It is imperative to adapt the richness of your skincare to the climate calendar.

2. Abandoning vitamin C serum in winter for fear of irritation: Vitamin C is not photosensitizing and does not contraindicate its use in winter. On the contrary, it is during periods of low sunlight that the skin most needs support to preserve its firm and plump appearance — vitamin C serum helps maintain radiance regardless of UV. Maintain it, simply adjust the texture of the base and the occlusive treatment layered on top.

3. Applying active ingredients to dry skin in winter: Mature dry skin in winter has an accentuated micro-relief that prevents even distribution of serums. Always apply your active ingredients (vitamin C, hyaluronic acid) to slightly damp skin — the residual water layer significantly improves the distribution of hygroscopic molecules.

4. Over-exfoliating during seasonal transitions: Seasonal changes create a temptation to exfoliate to "renew" the skin. For mature dry skin, too frequent exfoliation during periods of climatic stress (early winter, late summer) can strip the stratum corneum of its protective corneocytes at the very moment when the barrier needs them most. Maximum once a week, with gentle enzymatic formulas rather than acidic AHAs.

5. Ignoring the impact of indoor heated air: Central heating reduces indoor relative humidity to 20–30% in winter — almost as much as the cold outdoors. Skin has no "season": if you spend 16 hours a day in air with 25% relative humidity, the impact on your TEWL is the same regardless of the season. Humidifier + daytime moisturizing treatment (toning mist, light serum) are habits to maintain from the first use of heating.

6. Neglecting wind-exposed areas: neck and décolleté: The neck and décolleté areas suffer mechanical abrasion from wind as much as the face but rarely receive the same care. For mature skin, these areas are the first to show signs of a weakened barrier due to wind exposure. Extend your face routine to the décolleté, especially in the evening for comfort and repair.