yes there is no doubt about this that loans are too risky if you are load to some for investment in bitcoin or to invest it in some other place and lost the money then what will you do. i think you will never recover your loan from him.
Of course before you are going to loan make sure that you have your source of income and you are just loaning because you need to add some capital for your investment. And don't loan because you don't have money or bitcoin because if that is your reason you are not going to be approved by the lender or any lending website.
I have not tried lending money here online because every time I need money I just approach a lending firm here in our place. I can see they are growing their business so that means lending is profitable in the actual world but not here online.