Walk through any supermarket or pharmacy in the U.S. today, and you’ll find a multitude of protein powders to choose from: whey, plant-based (like pea, rice, soy, hemp), casein, collagen, and egg. Regardless of the type of protein powder, the supplement is not regulated by the Food and Drug Administration, which means protein powders can contain ingredients like added sugars, caffeine, and even high levels of arsenic. While choosing a protein powder based on what’s viral on Tiktok might be...