In general, Whey Proteins are not likely to cause significant side effects in most people. However, certain people may be at a higher risk for side effects, for example, lactose intolerance can lead to some of the below effects.

Whey Protein is an excellent source of protein to help with the rebuilding of muscle after a workout and is easily digested by the body however that does not mean it is right for everyone. There are some side effects you want to be aware of before you start taking whey protein.  I wish I had this information before I bought my first whey protein supplement. After I started taking the shakes I realized something was not working the way I had hoped – I was feeling bloated and full and looking rounder than before I started the supplement.

It appears that although whey has countless benefits it also has some side effects such as increased bowel movements, fatigue and lethargy, loss of hunger, headaches, dry mouth, bloating and cramps. Well, I must say that although I love to think I am fueling my body after an intense workout with serious rebuilding protein, I don't want to suffer from any of those side effects.   

Turns out there are some unrefined forms of whey protein which can exacerbate these conditions especially in people who are lactose intolerant.  Historically this form of protein was once a low-grade waste product which dairy farmers would toss out. These products had as little as 30 to 40% protein  and were saturated with lactose and fat. Now however it is a high grade protein filled with healthful benefits like disease fighting properties.  

Life Extension has stayed current with the highest quality whey formulation and are be ranked among the leaders in brand recognition of protein supplements.
There are two tiers currently of whey formulations – second generation and third generation. Most products sold today would be considered second-generation whey protein supplements, including the former Life Extension Protein formula.
The majority of the second-generation proteins have whey isolates mixed with the concentrates and have maybe 50% protein.  Third generation protein supplements are up to 90 – 96 percent protein and are low in fats.   Removing the lactose and fats from the protein is critical and must be done with precision to maintain the integrity of the supplement.
If there is a drawback to the higher quality or third generation protein its the cost, higher quality equals higher cost but if your goal is to build a better body than why would you scrimp?  Life Extension's Enhanced Protein supplement is a third generation protein and contains 100 percent  whey isolates. This means you are receiving high quality nutrients and the risk of side effects is low.