Actually, learning that Sly was up before the beak in Oz accused of importing Human Growth Hormone sent me scurrying to Wikipedia. Here's the skinny:
Prolonged GH excess thickens the bones of the jaw, fingers and toes. Resulting heaviness of the jaw and increased thickness of digits is referred to as acromegaly.
Accompanying problems can include pressure on nerves (e.g., carpal tunnel syndrome), muscle weakness, insulin resistance or even a rare form of type 2 diabetes, and reduced sexual function.
A comparison of the evolution of his features with the symptoms described above furnishes pretty scary circumstancial evidence. (Hint: Muscle weakness and reduced sexual function is not a small price to pay for a stonger jawline and thicker toes.)
Jintoprin, the product in question, sounds like something out of a Chiba City black clinic a la Neuromancer
A mad world my masters.