The recommended daily amount of protein (RDA) is .8 grams per kilogram of body weight. That’s approximately .36 grams per pound of body weight. So, for example, someone who weight 150 lbs need about 54 grams of protein per day.
Because protein is used for building and repairing muscles and tissues, anyone whose body is doing more of this building and/or repairing will naturally need higher requirements of protein, even as much as .9 grams per pound of body weight. That would be 135 grams of protein for a 150 lb person.
Protein Dosage if Deficient
If you have protein deficiency symptoms, or issues that may be helped by the amino acids in the whey protein powder, such as heart or cardiovascular issues, diabetes, weight issues, depression or anxiety, cancer, etc. you might want to consider a higher dosage than the .36 grams.
Whey Protein Powder: Typical Serving
A typical serving of whey protein powder has 15 grams of protein, so eating a serving or two would not generally be too much, depending on what other protein is in your diet, how much exercise you get, etc. (see above).
If in any doubt, please ask your health care practitioner, especially if you are taking other supplements and/or prescription medicines or are being treated for a specific disease.