It pumps you up and makes you bigger!
Steroids enhance the users body by increasing strength, endurance, or durability. Unlike the prewar steroids, post-war steroids are very diluted and have very little effect in comparison.
Roll a d4 to determine which trait the steroid increases:
4) Player chosen.
The steroids found in the post-war world are very diluted forms of older steroids. Wanted for their body enhancing effect, they have become very rare. Adventurers, raiders, and military groups often horde any steroids found for either self improvement or to use as a very powerful bargaining item.
Because the steroid has been so diluted, it shows none of the mental effects of pre-war steroids. This, however, comes at the price of being much weaker than pre-war steroids.