Should startup loan be repayed out of salary or as business expense?

I am in the very early thought process of starting a business with a friend. He was going to get financing from his mother as a gift, but realized the startup costs would be too much. I decided I would put together a business plan and go to a family member to get a loan or investment. My question is, if my friend gets half of the startup capital as a gift and I get the other half as a loan, should that loan be repayed as a business expense or should it be a personal loan that I repay out of my salary?