The term "steroid" encompasses many things
and refers to a type of molecular structure. For example, cholesterol is a steroid, as is protodioscin (active ingredient of Tribex-500) or guggulsterone (used for example in Prolab's Metabolic Thyrolean.) So are estrogens, cortisol, and for that matter 4-AD. Many things.
The differences between MAG-10 and pharmaceutical anabolic steroids are legality for use without a prescription, and also MAG-10 does not have the adverse effects many of them do of increasing estrogen levels, or of being converted to DHT, or of being liver toxic.
There are no potentials for kidney problems or sterility.
If you use MAG-10 to simply get faster to where you could have gotten anyway with natural training, then you can retain what you gain except for some loss of the extra glycogen that's stored in the muscles while "on," and glycogen associated water. If you use MAG-10 to go beyond what you could ever have achieved naturally, you can expect to retain long term about half of that improvement.