To me leverage is immaterial. It's just a tool to help you get in a trade with less money. If you use 1:500 leverage, it does not mean you will lose $500 for every point the market goes down.
The real question is how big a STOP LOSS you use as a percentage of your Trade Account size. Using improper percentage as your stop loss is the real killer for most traders.
I use 2% max as my risk capital for each trade that take. When I trade ES with two contracts, my stop loss is set at 2.5 points from my entry. Which means I have 2x2.5=5 points x $50=$250.
To backup this trade, set with $250 risk money, I have $12,500 in my account to keep my risk tolerance not to exceed 2%.
Think once again, is the real killer Leverage or Risk Tolerance ?