Do protein supplements have any side effects?

Do protein supplements have any side effects?

Unfortunately, most of the protein study has focused on effectiveness (or usefulness) rather than harmful side effects. That is, excess protein (beyond what the body needs to build muscle) is broken down in the kidneys to become glycogen. Drinking plenty of water makes this process easier and keeps your kidneys happy. However, if your kidneys are not working normally, excess protein can be dangerous for you.

Based on a study by Consumer Reports of available protein powders, there are now other harmful chemicals that are present in higher densities than in naturally occurring foods. These are things like cadmium, arsenic, etc. The numbers in the table indicate the loading of the chemicals in 3 servings of the protein. The protein maker's response challenges the study, stating that the CR report had an agenda.

Even so, there are a few reasons why you shouldn't build more muscle:

  • You haven't worked enough to adjust the body (see Practical Programming by Rippetoe and Dr. Kilgore [book]).
  • The body's adaptive systems did not have the resources to hypercompensate. (see same resource)

Your trainer believes the problem you are facing is the second point. In essence, your body needs enough protein , Calories and Quiet to build the muscle needed for more work.

Underweight (by weightlifting standards) lifters will encounter this problem all the time. Protein powders are simply a way to get that extra protein and, in many cases, calories. Another avenue is the Gallon of Milk a Day (GOMAD) approach which has the same effect for probably less money and less risk of having too much of the nasty heavy metals included in the CR report. NOTE: If you run GOMAD, do not do so for more than 8 weeks at a time. They also retain water that disappears after drinking a gallon of water every day instead of milk.


I've seen this table on dangerous metals in protein powders before. I've always wondered why the more expensive protein powders have a lower dangerous metals to protein ratio than the cheaper powders. I thought if you pay more you are paying for less fat / cholesterol / carbohydrates and faster absorbing protein. Why should you have to pay more to avoid being poisoned? Promoting the safety of the powder was, to my knowledge, not a marketing point for a supplement company.

Berin Loritsch

Has to do with processing and quality control. The more expensive powders go through stricter quality controls and bring you better protein. Until the CR report, no one questioned the amount of dangerous metals in protein powders.

JohnP ♦

I would like to point out that the CR report is a bit skewed as not all samples of the protein additives tested gave abnormal results and not all protein additives were tested. It's a bit alarming and is meant to get people to buy the magazine / article.


There is a wonderful page that supplements for life review: and! They also measure the amount of metals !! I think the cheap ones have more poison because it's more expensive to filter ... anyway, the FDA should enforce maximum levels on these substances