A viral headline claims sunscreen "causes" skin cancer. Here's what the 470,000-person study actually found, what it can't tell us yet, and the sun-exposure research that rarely makes the news.

Nickel allergy is the most common contact allergy, and for sensitized people it can reach far beyond the skin into the gut, the microbiome, and possibly the thyroid. This guide covers the links to eczema, IBS and IBD, inflammation, hormones, and cancer, where nickel hides from cheap jewelry and 18/10 cookware to braces and high-nickel foods, what Ray Peat taught about nickel and pans, and practical ways to lower your exposure.