Collateral is a must, and most of the time the offered collateral is the forum account here in bitcointalk. That is why most of the users who can get loan is the higher rank and no newbie can get a loan.
That is why loan is very risky method to earn bitcoin, much better to give loan personally which you know the person who applying and you can chase them if they do not pay.
Most lenders do not accept forum accounts anymore because if the person defaults on the loan now they have to sell the account to recover their money and many do not like this activity since they are against it since account sales most of the time leads to scams.
That's the risk, but there are some who just let you borrow money for a little amount because they trust you and they believe with small amount there will be small risk. When lending in this kind of weak collateral transaction, lender should be wise to charge a bigger interest rate to match the big risk in this kind of transaction.
There are lenders like that but most likely you need to have a story of repaying bigger loans to them or to other lenders or you need to have a good reputation in the forum already, however with the big amount of scams going around in the forum those kind of loans are slowly disappearing from the forum as scammers have began to abuse the trust of those lenders.