At 21 you shouldn't need much to grow. I'm not trying to be a dick, but I'm a bit confused. In your first post you say you've run a few vials, but never a cycle, but as I read you keep stating that you've done cycle(s). Maybe elaborate more on what exactly you've run in the past (compounds, doses, lengths...). Also, maybe give us an idea of what your food intake looks like because like the other guys I'd be willing to bet that you're not eating nearly enough. If you can't grow off of 500mg, I will guarantee one of two things is the reason 1)it was garbage and either highly underdosed or just completely junk or 2)you're intake is not even close to what your body is requiring to grow
You are slightly tall and thin so I'm sure that you can pack on 15-20 pounds in a year with a clean diet with a lot of calories. And that'd be without any gear