The unfortunate answer is there is no way to tell. Consumer Labs (CL) and the United States Pharmacopeial Convention (USP) are the most widely respected testing bodies for consumer products; however, CL does not test every year and when they do, they do not test every brand. USP has a voluntary program in which companies must pay to be verified. As far as I can find, there are no protein powder supplements that have the USP seal.

There have always been problems with different protein powders. According to CL, some do not have the amount of protein claimed, some have more sugar than claimed and more than one professional athlete has sued a manufacture when he failed to pass a banned-substances test after switching to a new brand of supplement. There are some brands that are known to be worse than others. Muscle Milk and EAS brand products consistently test high for heavy metals like arsenic, lead and cadmium, which no one needs. The most recent round of freely available testing data I can find is from Consumer Reports (July 2010). In that test, Solgar Whey to Go Whey Protein Powder Natural Vanilla Bean had the least amount of heavy metals. There is a more recent report available here on Consumer Labs, but it is fee based. I’ve let my membership lapse, but if you decide to join, let us know what it says!

If you are set on adding a powdered protein supplement to your diet, there are several questions to ask before you buy.

1.  Are there artificial ingredients? Keep looking.

2.  Are there other ingredients that you don’t need? Do you even know what all the ingredients are?

3.  Are you vegan or lactose intolerant? Hemp or pea protein might be a better supplement for you than the most popular whey protein.

4.  Does this brand have a history of side effects? Search the web and find out. People will report bad experiences on forums and other places.

5.  Is there testing available showing that this brand is heavy metal free?

6.  Is it at least GMP (Good Manufacturing Practices) Certified?

7.  Particularly for whey protein, is it from hormone-free sources?

Now that you have found your dream supplement, keep track of how you feel after consuming it. Does is make you nauseated, gassy or bloated? Are you experiencing diarrhea, a side effect of too much protein? Then it might not be the right supplement for you.

Read this article from Consumer Reports if you didn’t already follow the link above. It is filled with pertinent information.

Whole foods are almost always the best alternative.

Finally, remember to always talk to you health care provider about the supplements you take. They may have a good reason for you not to, or they may want to perform blood tests to make sure that you are not having adverse effects from the supplement.