Just scar tissue buildup for me. No special growth or anything. Just your typical inflammation for a few days and that's it.

From my understanding of the compound called synthol is this...
I realize we aren't talking about synthol but I do believe there might be some science/intelliegent thinking behind my next statement.

synthol is used in larger quantities to STRETCH the fascia (outer layer surrounding the muscle).
some peoples fascia is tighter than others and even in certain bodyparts their fascia is more "taught" than in others.

For example people aways tend to mention and Im in no way looking to put down any comments at all just my thoughts on the matter but people say things like "ppl would have huge asses around here".

We are constantly stretching out glutes and glute fascia multiple times a day, making it more flexible and not as constrictive.
So if I were to use synthol (which I have no intentions of doing) id inject in my biceps. Our biceps don't get the continuous stretching on a repetitive basis daily as our glutes do. Sitting up and down 100 times, walking etc.

I believe that my bis are slower to grow due to the fact that the fascia surrounding my bis is VERY constrictive. Hence why people inject multiple CCs of synthol in order to stretch said fascia.

I hit delts 2x a week (2ccs of AAS) and ive noticed significant growth as opposed to larger ass growth.
Im guessing here that by using the 5/8 inch needle im not SO deep into the mucle that im possibly stretching the fascia somewhat and then doing shoulders that day is allowing for some growth that would be otherwise more restricted.

this is my guess and my rationale alone but that's the reasoning behind the synthol useage
fascia stretching.
if I had the balls to do outer bis id try it but I got some pretty big spider veins going on in that area and im too nervous to jack my injections up

I'm not gonna lie, I pinned my biceps about a week ago with 1/4ml of Deca 300, and they are still swollen and red. I'm not in the slightest worried about it, I realize what it is and it'll go away, but holy shit that virgin pin is absolutely brutal. It has reminded me that I need to rotate injection sites more often. I had always been a quad pinner. IDK that I'll try the bicep again. Does it make a difference? I don't think so.

I have done triceps and biceps. They will inflame and you will notice more girth un the area. It goes down eventually. Best way yo do it, is to consistently hit that spot scar tissue will form and may add slight size. (from what I. Told) I've never stuck with it long enough.

Honestly tho the difference is most likely negligible and not really worth it.

edit: also the idea is to inject the muscle before or after training to add to the stretch of the muscle.