Australian Sport Mineral Sunscreen Lotion

Zinc oxide is the right chemistry for a long day above treeline or on snow: it blocks broadly, it works on contact rather than needing to absorb, and it does not degrade under sustained UV the way some chemical filters do. This one is SPF 50+, water-resistant to the FDA's 80-minute maximum, and free of oxybenzone and octinoxate, which matters if you swim in alpine lakes. It behaves like mineral sunscreen, though, and that means a white cast that is obvious in photos and considerably worse on darker skin, plus a thick texture that is hard to spread when the tube is cold. It is slippery, too - it transfers onto sunglasses, pole grips, and phone screens. The 80-minute rating means reapplying every hour and a half of hard sweating, which almost nobody actually does. And a five-ounce tube is 142 grams; decant into a small bottle rather than carrying the whole thing.