This question might be too vague to answer but I might as well give it a shot.
Is there any difference between steroids and a testosterone booster, the ones that can be bought at the local health store?
Steroids are hormones that are external to your body, that you then put in your body. They include testosterone and other substances that are made of testosterone molecules that have been modified in some way. They actually tend to shut down natural production temporarily.
Natural testosterone boosters you get from supplement shops are just things that make you produce more testosterone. Like Tribulis for example. Biotest tribulis gold is pretty good.
Prohoromones are things that convert to another horomone when inyour body. So they are external like steroids rather than something like trib that makes you produce a little more. But they don't do anything in the form you take them in. They have to react with other things in the body to become another hormone.
That is why by definition, superdrol is a steroid. Even though it is still legal right now. It does tend to get pulled off the market when it pops up though. But the same substance gets released again under other names. I am sure the substance itself will eventually be banned though.