The inability to pay for such loan from your friend will destroy your reputation. The banks don't care if you're able to pay or not because they can simply talk you out to let them sell your collateral. It's even better if you take a loan from the banks because they are going to analyze your business plan whilst borrowing from your friend will just require nothing but trust. Many business people ask from the bank for loans because it's way better. There would be no friend spreading rumours/BS about you, no friend asking about the loan constantly, and the banks pretty much don't bother you unless you don't pay them for a while.
I think this is why when borrowing from friends it's better if you borrow from a lot of them so that you only take a small amount from each of them. If it's something that they can afford to lose anyway, maybe there wouldn't be much bad blood between the two. I'd prefer announcing to family and friends that I'm up to something, it might fail and that they can pitch in with whatever amount they want to to help out.
For banks I heard it's always better that you also have savings about the same amount as you are borrowing. At first I thought it was ridiculous but then again if the business bombed you can use the savings to pay the debt and you still have a good record with the bank and so would be able to ask for loan again in the future