Where effort meets information
Over the years, companies have developed alternatives to Whey Protein. This was in response to people out there that are allergic to milk products, are lactose intolerant, or may just avoid dairy due to other dietary restrictions. Other protein sources that have been cultivated into powder form are Beef, Chicken, Hemp, Pea, and other plants and vegetables. The proteins are extracted from the material in many different ways, then it is turned into powder, just like Whey.
There are many plants out there that actually contain very high levels of protein to meet the dietary needs of vegans. Soy, Quinoa, Chickpea, and Chia are just some examples.
Soy protein is extracted from the soybean. It goes through an interesting process where the beans are separated from the oil it contains. What is left over is flakes of the bean. These flakes are then dried and become the base of the supplement. Soybeans are rich in protein and removing the fat makes them basically pure protein. Just like whey, there are Concentrates and Isolates, Isolates being more processed but more pure protein. Again, it's debatable if this is truly a good thing worth the extra processing. There are other benefits in soy other than just the protein.
Soy got a bad rap when it was thought it increases estrogen levels and lowers testosterone, however this is likely only in extreme usage.