@dabbler Good point. Upon further thought, I have realized that we have been assuming a military in a culture like America or Western Europe where we have a certain degree of concern for the well-being of our fighting forces that others may lack.
First, let us look at history. The Middle East has a history of suicide bombers. During WW2, the Allies were willing to fight even if they had to die, but Japan seemed willing to die even if they had to fight; they pioneered “terminally guided munitions” in a pre-computer era. China has a large enough army that, before nuclear weapons, they could win a war simply by making the enemy run out of ammunition before they ran out of troops.
A culture who considers their troops more expendable than we do would have no concerns about long-term health effects. However, steroids still wouldn’t be the way to go as we don’t fight teh same way we did in the Middle Ages. Stimulants and opiates (painblockers for increased damage resistance) would be far more likely. There’s no way to make a person inherently bulletproof, but jack them up on enough PCP to not notice they’ve been shot and the net effect is the same, and cheraper than body armor. Add in enough amphetamines to make them hyper-aware enough to see sounds and taste colors, and things could get interesting.