What is the difference between testosterone and steroids?

What is the difference between testosterone and anabolic-androgenic steroids (AAS)? Well, while testosterone is produced naturally in the body, AAS are synthetic analogs of testosterone.

This may also help in explaining things further for you.

All About Testosterone (http://www.bodybuilding.com/fun/vm12.htm):

Testosterone is a steroid which is produced in your body. Men produce more than women, and things like your age, diet, and workouts can affect how much you produce.

When people talk about "steroids" they often mean additional testosterone which is injected. This should only be done under medical supervision to treat cases of genuinely low testosterone.