Yes—protein powder can be used during weight loss, but the purpose should be to meet protein needs while maintaining a calorie deficit. Weight loss is ultimately driven by total calorie balance. Protein powder may improve satiety and help preserve lean mass when dieting, especially if it replaces lower-quality snacks. However, protein powder still contains calories, and adding it on top of your normal intake can slow or stop fat loss. A practical rule is to use it as a replacement, not an addition—for example, swap a sugary snack for a protein shake. Choose products with higher protein and lower added sugar to fit a fat-loss plan. The best results come when protein powder is part of a structured program that includes balanced meals, regular activity, and adequate sleep. If you have conditions like diabetes, kidney disease, or thyroid issues, personalization with a professional is recommended.