WPC (whey protein concentrate) and WPI (whey protein isolate) are derived from the whey of cows milk and are both exceptionally high-quality sources of protein. The only significant difference between the two is the degree of processing and filtration. WPC goes through a ultrafiltration process where the filters are approximately one micrometer in diameter (insanely small!). As a result WPC is approximately 80% protein by weight, 5-7% milk fat, and contains a moderate amount of lactose. WPI on the other hand goes through a lengthier filtration process, with filters approximately 4 times smaller than those used to produce WPC. As a result WPI is around 90% protein by weight, 1-2% milk fat, and is virtually lactose free.
It is important to note that although WPC contains slightly less protein than WPI, it's higher fat and lactose content can provide anabolic growth factors, essential fatty acids, anti-microbial peptides and immune regulators, all of which support muscle growth and a healthy gut biome, and are not usually present in WPI due to the higher filtration process. Therefore, when it comes to choosing which protein powder is best for you these are a few things to consider! If you're lactose intolerant, on a very low calorie diet and/or have a few extra dollars to spare, then WPI might be the best choice for you! However, if you can tolerate lactose, don't mind an extra 5-10 calories in your scoop of protein, and want to save a little money, then purchasing WPC is still an excellent choice! As mentioned earlier, WPC and WPI are fast digesting, high-quality sources of protein that will both support muscle growth and recovery following an intense workout.