Protein powders are not regulated by the FDA, which is why they can contain different amounts of vitamins, fillers, or sweeteners. Reading the Nutrition Facts label on a protein powder package is important for a complete list of ingredients, macros, micros, and more.
The best protein powders will also have protein labels that illustrate if they are certified, third-party tested, and the different allergens they possess or do not. Transparency is important to look for in the best protein powders.