Vitamin C, known for its antioxidant properties, can offer a degree of protection against environmental stressors like UV radiation and pollution. The set's niacinamide is recognized for strengthening the skin barrier, which is crucial when facing harsh winds that can strip natural oils. While not designed as a physical barrier like specialized windproof balms, the fast-absorbing, lightweight formulations aim to provide hydration without a sticky residue, potentially mitigating dryness and irritation associated with windburn. The moisturizer and body lotion, with their intended hydrating effects, would be key components.

Skincare formulations can change viscosity in cold temperatures. While UZTUZT describes its products as 'lightweight and fast-absorbing', extreme cold, such as -5°C, might affect the texture and absorption rate. Ingredients like humectants (e.g., glycerin, often found in moisturizers) can draw moisture, but their effectiveness can be reduced if the water freezes. The set's primary focus is hydration and daily care, not extreme weather protection. It's advisable to monitor for any thickening or reduced spreadability and consider a more occlusive balm for direct, prolonged exposure in such conditions.

The UZTUZT set emphasizes 'fast-absorbing textures' that feel 'smooth on skin without heavy or greasy residue'. This suggests a formulation designed for minimal surface tackiness, which is beneficial post-sweat. However, heavy exertion, especially in high humidity, can still lead to some product migration on the skin's surface. The serum's efficacy relies on its ingredients like Vitamin C and Niacinamide penetrating the skin rather than sitting on top. If formulated with a high percentage of water-soluble ingredients, it might be more prone to streaking than a silicone-based primer.

As specific weight and volume details are not provided, an accurate calculation for backpacking is not possible. However, typical skincare product sizes for a 6-piece routine range from 15ml to 100ml per item. A conservative estimate for the entire set could be between 300ml to 600ml total liquid volume. If each 30ml bottle weighs approximately 30-40 grams, the set could weigh between 180 to 240 grams. For ultralight backpacking, decanting into smaller, travel-sized containers (e.g., 10ml or 20ml) would be key for weight and space optimization.

Vitamin C, particularly L-Ascorbic Acid, is known to degrade when exposed to light, air, and heat. UZTUZT's claim of 'hydrating' and 'daily face care' implies a formulation that balances efficacy with stability for everyday use. Without specific details on the type of Vitamin C derivative used (e.g., L-Ascorbic Acid vs. Sodium Ascorbyl Phosphate), its concentration, or packaging (e.g., opaque, airless pump), predicting stability under constant outdoor temperature fluctuations is challenging. Products designed for travel often use more stable derivatives or protective packaging to mitigate degradation over time.