[Oldgixxer]

You're referring to Syntherol,it's been popular in competitive bodybuilding since the mid-2000's. There's a detailed science behind it but I won't get into all of that..but basically,it's a site-enhancing oil that stretches the fascia tissue when injected directly into the muscle belly. It's primarily used for a lagging bodypart before a BBing contest and is temporary.

The original site enhancing compound was an Italian drug called Esiclene and it produced temporary swelling when injected into the muscle but was water based unlike Syntherol. Thats been around since the 80's but was never really popular and extremely hard to get.