Leverage does not actually improve your risk/reward profile. What that means is that although with £100 or $100 you could make more money with leverage (which is where the broker lends you money) you could also lose more too.
So although leverage can improve your return on your capital (like borrowing money from a bank for a mortgage allows you to buy a bigger house and so a bigger profit if it goes up in price) it can also mean a bigger loss on capital.
Also our return shows those using the least leverage eg 1:1 as opposed to 1:400 ie they lend you $400 for every $1 you put in, do better!
Most brokers force leverage on you. If you can use the least and trade based on your capital not on how much they lent you. So if you put $1,000 in your account, calculate your potential loss based on your $1,000 account not on the trade being, say, a $10,000 trade and you might make 10% ie $1,000 on a trade ie 100% on your capital.
Those broker links:
As the image shows below, less leverage led to more liklihood of profitability.
The image below shows how more leverage also increases chances of losing more money