Whey Protein comes from milk and makes up around 20% of its protein. The other 80% is called casein which is an ingredient in some other protein supplements. The whey must undergo several isolation processes to separate it from the milk itself.
If whey protein is pure, then you should be able to consume it without being effected by most of the allergies associated with milk as the triggers for most of these are in casein, however whey has still been known to trigger reactions caused by lactose intolerance.
So how much is the right amount of whey protein to take? Can you take too much? Well, the straightforward answer is yes, you can take too much, doctors will most probably advise that you use these supplements fairly cautiously as they have sometimes been known to have some harmful side effects.
The irony about one of the side effects in particular, is that working out and building your muscles too much and too quickly can result in not being able to work out at all. This is a risk you face if you develop gout, one of the nastier side effects of whey protein, but it is fairly easily avoidable.
Gout is a result of excess protein in your body that the body cant do anything with so it settles on your joints, muscles and tendons in your legs and feet (usually in your big toes first) as crystals of uric acid that cause joints to be stiff, brittle and painful.
Excess protein can also cause lasting damage to the liver and the kidneys, but as long as you follow any recommended guidelines you can find you should be alright (you do have to take quite a lot for gout to settle in). Different people require different amounts of protein for it to take effect, and the most prominent factor is deciding how much is right for you is your body mass. I would advise having a consultation with your doctor before you start on protein supplements to try and work out an estimate for you on how much to have.
So whey protein, we can conclude, is an effective source of protein for your body to lose unwanted fat or gain some lean muscle, but you should always do all the research you can before you start using supplements of any kind to make sure you wont be troubled by unwanted side-effects.