Anabolic steroid

http://en.wikipedia.org/wiki/Anabolic_steroid

Oh glorious injection,
Placed deep in buttock cheek
Flesh now worthy of inspection,
Once was flabbily weak
Banished are the muscle pains,
Accursed, that wracked a spindly man
Dreadful feeble fate avoided,
The body freed from mortal chains,
Its divine sinew nicely tan,
Praises God for being roided!