Are steroids sold on the street "real" steroids?

Because legal steroids are difficult to attain and because there is a huge demand for their potential benefits, a black market has developed marketing both authentic but illegally obtained steroids as well as counterfeit versions of the drugs. It is estimated by many that more than half of the steroids on the black market are counterfeit. These drugs, often indistinguishable from the real thing to even the well-trained eye, present additional danger to users.

Manufactured in underground labs, outside of safe pharmaceutical practices, these drugs can become contaminated creating additional health risks. Dosage levels are impossible to accurately determine and therefore "safe as possible" use by even the most knowledgeable of users is compromised.

Often times, substances sold as steroids aren't really steroids at all. You can pay a lot of money for vitamins.