the first rule of any investment (not just bitcoin) is to invest what you can afford to lose. a loan is not the money you can afford to lose so in other words you should never do something like that. start small, invest what you have in your pocket and spend on pizza!!!

and no respectable financial firm is going to give you a loan to invest in cryptocurrencies that are a highly volatile because your investment is consider a high risk one and if you are lucky you may get a huge rate for return which is not even going to be profitable for you. unless you take the loan for something else and then invest it in bitcoin which is still not wise.