Protein powder is a dietary supplement that is made from one or more of four basic sources of protein: whey, eggs, soy and rice. These concentrated sources of protein are processed into powdered form, which can be reconstituted into liquid form as a protein shake when mixed with water, fruit juice or milk. Protein powder also can be sprinkled on cereal, stirred into soups or stews, mixed into other types of food or cooked into baked goods and other meals.
Bodybuilders and athletes have long relied on protein powder to make sure that they get the high levels of protein needed to build up their muscles through lifting weights and exercise. Research has shown that ingesting protein powder every day also can boost immune system health, facilitate the healing of wounds after surgery or injury and promote healthy skin.