Mad Hippie Sheer Tint Sun Serum SPF 29 - A zinc oxide sunscreen that leaves no trace - just soft, smooth, protected skin. A hint of mineral tint allows for a flawless application that blends into all skin tones and an antioxidant boost to protect skin from damaging free radicals. All of Mad Hippie sunscreen products utilize nano-free zinc oxide rather than chemical UV absorbers, which are known endocrine disruptors, and wreak havoc on the fragile environments of lakes, rivers and oceans.