Was the 'super soldier serum' that was injected into Emil Blonsky and Bruce Banner (by himself just before he was subjected to gamma radiation) the same serum or were they different in some way?
Let's examine the expository scene wherein Ross discusses the Super Soldier Program for the first time:
Ross: Let me emphasize that what I'm about to share with you is tremendously sensitive, both to me personally and the Army. You're aware that we've got an Infantry Weapons Development program. Well, in WWII, they initiated a subprogram for Bio-Tech Force Enhancement.
Blonsky: Yeah, Super Soldier.
Ross: Yes. An oversimplification, but yes. And I dusted it off, got 'em doing serious work again, bold work. Across the hall, they were trying to arm you better. We were tryin' to make you better. Banner's work was very early phase. It wasn't even weapons application. He thought he was working on radiation resistance. I would never have told him what the project really was. But he was so sure of what he was onto, that he tested it on himself. And something went very wrong. Or it went very right. As far as I'm concerned, that man's whole body is the property of the US Army.
Blonsky: You said he wasn't working on weapons, right?
Blonsky: But you were. You were, weren't you? You were trying other things.
Ross: One serum we developed was very promising.
Blonsky: So why did he run?
Ross: He's a scientist. He is not one of us. Blonsky, how old are you? 45?
Ross: It takes a toll, doesn't it?
Blonsky: Yes, it does.
Ross: So get out of the trenches. You should be a Colonel by now, with your record.
Blonsky: No, I'm a fighter. I'll be one for as long as I can. You know, if I could take what I know now, put it in the body I had ten years ago, that would be someone I wouldn't want to fight.
Ross: I could probably arrange something like that.
It is categorically established in the movie itself that the serum that Blonsky got wasn't the same one. The fact that Blonsky suffered side effects from the serum (ie his spine protruding) and Banner didn't also reinforces the idea that they were different serums. However, one can argue that Blonsky only exhibited side effects after the full dose and the initial doze he got was a lower one and since Banner only received a single dose, Banner might have injected himself with a lower dose as well. Then again, one needs to realize that while Blonsky's dosage was being personally controlled by Ross via the technicians therein, the same was not the case with Banner. Banner went on to subject himself to the serum in the first place cause he was sure of himself and his work, cause of his cockiness, which is further evidenced by his calm demeanour and his wink to Betty just before he is about to be subjected to gamma radiation. His overconfidence is what lent itself to him subjecting himself to it. The man, who happens to be a civilian, chose himself as the first human subject for a previously untested and newly developed serum for the US Army even though he had absolutely no obligation to, all because he was overzealously cocksure of his work. There's no reason as to why he'd be cautious about the dosage and not take the full dose. Moreover, given that it was a different serum, Blonsky was receiving a low dose just to see how his body reacts to it, while Banner was going to be subjected to gamma radiation directly, so he would've most likely injected himself with the full dose anyway.