Most people who buy protein powder probably never stop to think about how much of the powder is actually protein.
Protein powders can be made of many sources including whey, casein, egg, milk, soy or a combination of these. The powder that is in the container will have some amount of measureable protein along with some sugar, fat and the flavoring.
So when you're buying a protein powder how do you determine how much protein you're getting and how much of the other stuff you're getting?
First of all when you read the label look at the difference between the grams of protein per scoop vs the total grams of powder per scoop. The difference in these two numbers is what will tell you what kind of quality you are dealing with. The bigger the gap between the numbers the more sugar and fat is in the product and the less protein there is.
Most good protein powders use an 80% concentrate. That means that 80% of the powder is protein, and the rest is whatever sugar and fat is left over. You can get an even more concentrated form that pushes the protein content up to 90%, this is called an isolate.
Keep in mind this is just the raw protein powder without any flavoring added to it. Once you add some flavor (which almost all products have) then the percentage of protein in the total finished product drops.
So an 80% concentrate that has some flavor added to it will appear in its finished product form as having approximately 75% protein.
Likewise an 90% isolate with some flavoring added to it will appear as around 80% total protein.
Any product that is promoting a protein per scoop content at or higher than 90% would seem fishy to me as there is no explanation to where they fit the flavoring in.
If you have a product that is much lower than 75% then you can bet you're getting a lower quality powder that has a fair bit of fat and sugars and carbs in it.
Other things to consider when shopping for this sort of item are flavor, taste, mixability, container size, expiry date, reputation of the company and brand.
The supplement industry is largely unregulated by the government so there aren't really any quality control standards you can be assured of. This means it's buy at your own risk, in which case I would tend to default to a company that has a proven track record of customer satisfaction.
For the most part the big brands that have been around for a while do a good job with their products and there isn't much to worry about. It's the less known brands that seem to be selling at an unrealistically low price that might be worth avoiding.
As with any supplement it's up to you to decide how much you want to spend and what you expect to get out of it. When choosing a protein powder I suggest going for a middle of the road price point and a brand that has been around for a while. It's at least one way of trying to get a quality item without spending too much money but hopefully getting exactly what you paid for.