It doesn't take the oil years to go away anymore than the oil in your gear. It eventually makes its way to the portal vein where it's processed by the liver as food. I used to make my own site enhancement oil. All I did was sterilize USP MCT oil (NOW Foods brand) by heating it in a 250 oven for 1/2 hr. I then filtered through a sterile syringe filter and put 98 mls in a 100 ml vial with 2 mls BA to inhibit any possible bacterial growth. (2%)

Medium Chain Tryglyceride oil breaks down more easily than the grape seed or cottonseed oil most of you are injecting now. Some of these "Synthol-type" products were made adding collagen and shit though, trying to make them last longer, or alcohol for inflammation, and that's crazy imo. That's something totally different.

What I did was just add it to the test prop and tren A I was pinning every day. 1 ml prop + 1 ml MCT and 1 ml tren + 1 ml MCT. So 2ml each side. Maybe 2-1/2ml up to 3ml towards the end there. It's best to build up to it. I rotated between lateral delts, inner biceps, rear and lateral triceps, rear delts, outer biceps. It looked pretty awesome, but I didn't get all crazy like my arms are bigger than anything else. If they started getting too out of proportion I'd just switch to the outer edge of my lats or traps for awhile.

If you look at all the physique stars of the 50s-60s, it's obvious they were pinning their gear in their arms and shoulders. All the way from Larry Scott, Bill Pearl, Bill Grimek, etc to Arnold et al these guy's arm and shoulder development were way ahead of the rest of their physiques. And that biceps peak on Albert Beckles? C'mon man. So that's why I say "The oil's gotta go somewhere, may as well put it where it looks good." I don't bother adding extra oil anymore unless I'm pinning a high mg amount, just to spread it out, but I always pin upper body with short esters/frequent injects. In my experience it doesn't take years to go away.

It is also possible that injecting just oil without any gear could add size, not just from scar tissue, but from stretching the fascia. There was a study done years ago where they hung a weight from a bird's wing for 6 weeks or something and at the end, that wing was considerably hypertrophied relative to the other. I learned about extreme stretching from John Parrillo in the 80s and have practiced it religiously ever since. I believe this is also related to the damage/inflammatory response engendered by the negative portion of the rep.

So that's pretty much it.