There are SO MANY MLMs that sell bodybuilding supplements, you'll have a hard time finding legitimate companies. Here are some tips:
If a company or product matches ANY of these scenarios, it's a SCAM...
*Their trust seals do not lead to the company's listing or have no link.
*They charge to "become a member" before you can sell their product.
*They charge to hire you (real companies don't charge applicants).
*They claim market-defying, science-defying, or other miraculous results.
*They have no phone AND their address is a P.O. Box OR foreign country.
*They require automatic renewals/reorders OR have no cancellation policy.
*They require minimum levels of sales or recruitment to sell their product.
*They require payment by Direct Deposit, MoneyPack, or Wire.
*They require payment via email or other insecure connection.
*They require you send or wire money back from an overpaid check.
*They try to "dare" or "guilt" you into buying their product or joining.
*They use SPAM as an advertising technique.
READ THE FINE PRINT: If a company requires a minimum level of sales or recruitment, you will loose money--unless you're either skilled at sales or using their products or services. Also watchout for MLMs whose only products are instructions for how to recruit new members.
http://vandruff.com/mlm.html & http://en.wikipedia.org/wiki/Multi-Level_Marketing
http://consumer.ftc.gov/articles/0065-multilevel-marketing
http://business.ftc.gov/documents/inv02-looking-earn-extra-income-how-avoid-bogus-business-opportunity-offers
http://jobsearch.about.com/od/jobsearchscams/a/fake-job-scams.htm