Supplements are as much a part of weightlifting and body building as the weights are. With all aspects of training -there will always be a debate . The ongoing debate between Whey protein and Casein protein is still raging. It is sometimes hard to sift through all the opinions and get to the facts. Let the confusion end here and now. No more debating, let's get to the truth. Before jumping into the whey vs. casein argument, you need to know exactly what they are. Whey Protein Milk whey liquid is the fluid left over from the process of cheese making. During the manufacture of cheese, milk proteins are coagulated using either an enzyme called rennet or an acid, such as citric acid. The coagulated protein forms the basis of cheese, while the remaining liquid contains soluble whey protein (1). The liquid whey is sent through filters to remove all non-whey ingredients. It is then purified. The final step is removing the water from the whey at a drying tower. The protein powder is now ready to be wrapped up and sent to stores (2). It is a 100% pure, natural protein. It is a complete protein boasting an amazing 9 amino acids. Whey protein is very easily digested and metabolized. It is considered a "fast" protein because of how quickly it is broken down in the stomach and small intestines and dispersed to tissue in the body. Whey protein is high in leucine. Leucine is like the support beam of a house – it supports many different things and without it you'd crumble. Leucine lowers elevated blood sugar levels and stimulates the healing of bones, skin, and muscle tissue. Leucine helps you maintain muscle mass, which is crucial for long-term weight loss. More muscle helps you burn more calories. Supplements and protein powders that contain leucine are used extensively by bodybuilders and other athletes to promote muscle recovery. It also works to increase endurance and enhance energy (3). So that is whey in a nutshell. Casein Protein Casein also comes from Milk. Whey is made from the liquid, while the casein is a thick by-product. Casein is the most abundant protein in milk. During the processing of milk, which usually involves heat or acid, the casein is disturbed and as a result, a gelatinous material is formed (4). It is dried in a similar process to whey to create the powder form. Casein also contains the amino acids that whey does, except it is not so easily digested and metabolized. In the stomach, the casein forms into a somewhat gelatinous-type mass. Because of this, it is not quickly introduced into the blood stream for distribution to the tissues. It does get broken down, just very slowly and steadily – especially in comparison to whey protein. While Whey is high in leucine, casein is high in glutamine. Glutamine serves the same purpose as Leucine - muscle recovery, muscle mass, etc. (5) It also aids during times of stress - the body will pull the glutamine to burn. Because it is slower metabolizing, it also has weight loss effects. Again, it is chosen by weightlifters and bodybuilders as a prime source of protein. That is the breakdown of each. There are a few other notable points about each protein that may sway your decision either way: Whey Protein- Fast energy proven to aid in weight loss burns fat No side effects Lasts 1 – 2 hours Completely Safe Natural Safe for children boosts metabolism Casein Protein - Steady energy Aids weight loss burns fat Natural lasts up to 7 hours *somewhat safe Steady metabolism boost *has some side effects-thus not recommended for all children *People who are lactose intolerant have shown reactions to casein. Children with Autism have shown negative reactions to casein (6). For those who want to increase energy during their workouts, Whey protein is the suggested protein. Its quick absorption means it will quickly release the energy you need for weight training. This quick energy will last a couple of hours and then fade. It is the perfect amount for an hour or so training session. Before your next weight training, you will want to consume another dose of the whey protein to get the energy boost again. For those who are engaging in a longer training session or don't need the energy boost all at once, then casein would be your choice. Common Suggestions: There is a select group who will suggest only Whey. There is another group that suggests Casein only. But, there is also a third. The third group suggests using both. Taking a combination of whey protein and casein protein before a workout. The whey sends quick energy and the casein brings muscle recovery over a longer length of time after the workout. Another suggestion is to take the whey protein first thing in the morning and throughout your training day and then at the end of the day, before bed, take the casein. The thought process is good but one essential thought is not included – the cost. It may sound small, but it adds up quickly. Pure protein powder is a bit more expensive than the knock offs full of fillers and chemical additives (which you do not one to put into the body you are trying to get healthy). Instead of the expense of one protein powder, you are now spending twice the amount. It may seem petty, but in the long run you could really drain the bank. You now you know exactly what these two proteins are and can make a better informed decision as to which is better. . You need to take into account the manner in which you train, the frequency, what each protein can do for you personally and the total cost. The answer will ultimately rest on what sort of goals you have and even for your performance during your training times.