Davines offers deep treatments and styling products to combat dull, lifeless tresses. Winter’s fluctuating temperatures, harsh winds and dry air from heating can leave hair thirsty, brittle and prone to fly-aways. The company’s Nourishing Vegetarian Miracle ($19.50) is rich in keratin-building rice protein, ultra-moisturizing avocado and nourishing seaweed. The Nounou nourishing repairing mask ($21.50) is rich in emollient jojoba oil, the oil that most closely mimics the scalp’s natural oils, ac...