I am riddled with stretch marks. Some are nearly 8inches long and 1/2in wide running all over my delts, bis, pecs, armpits, lats...
This is what I believe:
Cocoa butter is a good way to prevent them but will not get rid of them once they appear.
They will never go away but over time will become nearly invisible. The tanner you are the less they will show up. Another way to help get rid of them is to you use a cream that helps peal off the top layers of skin. My doctor reccommended Mederma which is OTC and it did help somewhat but is expensive. I consider them to be a badge of honor bro, don't be ashamed of them.
Also, BIG TIP if you get the on one side they WILL appear on the othe side eventually so if you notice one starting on your right side put some cocoa butter on your left side ED to help prevent one from developing.
Cocoa butter simply increases skin elasticity, but does nothing for a mark that has already developed except possibly helping it from spreading but again COCOA BUTTER WILL DO NOTHING FOR PRE EXISTING STRETCH MARKS IMO...