You don't see steroids being used very often in anime or manga, but the times they are used, they are not fairly represented. Steroid use is one of those things that is the subject of much controversy and quite a lot of propaganda.
For instance, in Shamo, Narushima Ryo uses steroids to add more muscle mass before his heavyweight Lethal Fight match. However, apart from doing that, in the short time he uses them, Ryo's body almost collapses under the strain. Apparently in this universe, even short-term use of steroids causes massive liver damage and moderate insanity.
Also, in Grappler Baki, Jack Hanma uses steroids (and I'm sure a lot of other drugs) to be able to train non-stop and still get stronger. Although, I'm certain it would be physically damaging to take oral steroids like they were Skittles, the sheer stigma surrounding "doping" leads one to believe that it's the worst thing in the world. One is essentially "giving up tomorrow" when taking anabolic steroids.
Many athletes use steroids (whether they admit to it or not) and many private citizens do as well (more than you'd think), but we don't have mass murdering going on because someone popped a couple of anadrol or put a needle in his hip. People prone to violence while on steroids were probably prone to violence while not on steroids-- the only difference is that now they feel a greater sense of empowerment because of this extra "help." The physical ramifications of using steroids are generally blown out of proportion. If anabolic steroids are cycled properly, there has been shown to be little long-term side effects.
Moving on, anabolic steroids are not magic spells that give you muscles. On the contrary, the main function of anabolic steroids is to speed recovery so that you can train harder and more frequently, thereby adding more muscle, faster. It is slightly more complex than that, but that's what it essentially boils down to. If you sit on your butt all day and take steroids... you're still going to be out of shape, regardless of how many pills you pop.
As far as the morality of steroids go, I don't really see the problem with private citizens using them. As far as professional sports goes, if the organization wants to ban them, that's up to the organization and the players or athletes in that organization should abide by those rules.
What's wrong with steroids? Is it cheating? No, I think not. Is it cheating to eat healthy foods and train properly to pack on muscle mass? Anabolic steroids are just another tool for increasing your performance. If people would let go of the stigma and the emotional response they have attached to steroid use, I think they would realize that there's not really anything wrong with it. If you abuse them and you can't produce any more testosterone of your own, that's your problem-- your own stupidity. However, if you want to use them intelligently, just like any other tool, then great! Too much of anything is bad.
Knowledge is power. Don't take my word for it. Research it for yourself and see what you come up with. I don't use, nor have I ever used, steroids, but it is the principal of the thing. I can't stand to see something demonized for no reason. I also do not advocate the taking of anabolic steroids if it is illegal in your country. Don't break the law, because there are consequences for your actions, whatever you think the truth may be.
Sorry for the rant. If you disagree, feel free to post a response. :)
Until next time, good luck and train hard!