Yes, a non-exerciser can use protein powder, but the reason should be clear. Protein powder is best viewed as a nutrition support tool. If your regular meals do not provide enough protein due to low appetite, time constraints, or limited food options, a shake can help meet basic needs. However, without training, expecting major muscle gain is unrealistic—protein powder does not dramatically increase muscle by itself. Unnecessary use can also add calories and lead to weight gain. The best strategy for non-exercisers is food-first: improve protein intake through eggs, yogurt, legumes, fish/meat, and nuts, and use powder only if a real gap remains. Choose a simple product with low added sugar and minimal extras. If you have medical conditions, especially kidney or liver issues, consult a clinician before routine supplementation.