Like anything supplements are both good and bad. If you choose to buy supermarket or large discount supply supplements expect to get poor quality. Typically higher priced supplements are better quality but that does not mean you should not read the label. For example: There is a very well known brand of protein powder on the market that talks about how high a quality and all natural it is, until you read the label and find sugar alcohols in it. For this exact reason you have to do some research on whats right for you. Don't take the advice of a young bodybuilder working on commission because 9 out of 10 times they are using the product of the month.