Per many fitness diehards, whey protein is key.
However, some questions remain open such as what is the best form to take and what is the optimal time to do it.
What are whey Protein?
Whey comes from milk, which is actually made up of two Protein: casein which makes up about 80% and whey which makes up the remaining 20%.
When the cheese is made, the whey is separated from the solid curd and can be found in the liquid that is left behind during processing. Once separated, it goes through many processing steps to become what most people recognize as whey protein - a relatively tasteless powder that can be added to smoothies or protein bars.
Like all Protein, chicken, beef, egg, soy, rice, hemp etc ... whey is made up of amino acids, which the body can use for muscle growth and tissue repair. But it is the high concentration of branched-chain amino acids (BCAAs) in whey, particularly leucine, that sets this protein apart from others.
What are the differences between concentrated, isolated and hydrolyzed whey Protein?
- Whey protein concentrate: Whey concentrate contains about 80% protein and generally contains slightly higher amounts of fats and carbohydrates than the other two types.
- Whey Protein Isolate: Whey protein isolate has a fat and lactose content close to 0, with a protein concentration of up to 90%
- Hydrolyzed Whey Protein: Whey hydrolyzate is often referred to as "predigested" as it has undergone a partial digestion process. This reduces the assimilation time compared to the other two forms of protein. Both whey concentrate and whey isolate can be made into whey hydrolyzate, but the protein content can vary.
What is the best shape?
Reading from the above it is easy to think that hydrolyzate and isolate are far better than concentrate. However, there are no studies showing which form is best for muscle growth and tissue repair, so choose the one that best suits your lifestyle and budget.
If you are looking for a tasty protein and are on a tight budget it makes sense to stick to a whey protein concentrate. In this case, carbohydrates and fats are important for the product to be good and creamy. On the other hand, if you are looking for a low-fat, low-carbohydrate protein, a protein isolate is preferred. If you have mild lactose intolerance, or have mild gastrointestinal problems, you may want to try a whey protein isolate or whey protein hydrolyzate.
Benefits of whey protein
Whey Protein May Enhance Training Effects: Whey protein supplementation combined with resistance exercises appears to offer greater gains in muscle strength and muscle mass than resistance training alone. A study published in the International Journal of Sport Nutrition and Exercise Metabolism concluded that those who supplemented with whey protein during resistance training had an almost 5% increase in lean mass compared to those who did not. supplemented with whey protein. 
And compared to other forms of protein, like casein and soy, whey reigns supreme when it comes to major improvements in muscle strength and size. After an intense 10-week training program, the resistance-trained men who supplemented with whey protein isolate had significantly greater gains in strength and lean mass and a decrease in body fat, compared to the group who had. supplemented with casein Protein. 
Supplementing with whey protein is an easy way to increase your daily protein intake and, when combined with a reduced calorie diet, can help you lose weight. In a 2008 study, obese participants who were given a whey protein supplement lost significantly more body fat and maintained more muscle mass than the placebo group. 
How and when to take whey
- Before or after a workout as a supplement: Whey protein is commonly taken in dosages of 25-30 grams, 1-2 hours before training or immediately after training.
Delaying your whey intake can hinder muscle growth and repair, as well as make you feel more sore for your next workout.
- As a dietary protein source: whey between snacks during the day can be a valuable aid to constantly supply plastic material to the body to optimize muscle growth and repair.
Can you take too much whey?
Too much protein can lead to some GI disorders (and the dreaded protein farts), but there are no studies to suggest that higher protein diets can lead to kidney damage, bone loss, or dehydration in healthy individuals.   [ 6]
If you want to be systematic about the amount of whey to consume and avoid any digestive unpleasantness, calculate the recommended daily protein intake, then spread the intake across several doses of 25-30 grams throughout the day. Per many, this is a more sustainable approach than trying to cram as much protein into three meals as possible. Once you know the amount of protein to be consumed per day based on your lifestyle, body composition, diet and training, a whey protein supplement and a healthy diet may be enough to meet your daily intake goals.
 Candow, D. G., Burke, N. C., Smith-Palmer, T., & Burke, D. G. (2006). Effect of whey and soy protein supplementation combined with resistance training in young adults. International Journal of Sport Nutrition and Exercise Metabolism, 16(3), 233-244.
 Cribb, P. J., Williams, A. D., Carey, M. F., & Hayes, A. (2006). The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. International Journal of Sport Nutrition and Exercise Metabolism, 16(5), 494-509.
 Frestedt, J. L., Zenk, J. L., Kuskowski, M. A., Ward, L. S., & Bastian, E. D. (2008). A whey-protein supplement increases fat loss and spares lean muscle in obese subjects: a randomized human clinical study. Nutrition and Metabolism, 5(1), 8.
 Kerstetter, J. E., Kenny, A. M., & Insogna, K. L. (2011). Dietary protein and skeletal health: a review of recent human research. Current Opinion in Lipidology, 22(1), 16.
 Martin, W. F., Armstrong, L. E., & Rodriguez, N. R. (2005). Dietary protein intake and renal function. Nutrition and Metabolism, 2(1), 25.
 Bonjour, J. P. (2005). Dietary protein: an essential nutrient for bone health. Journal of the American College of Nutrition, 24(sup6), 526S-536S.