You can take a deduction for interest paid on a student loan. There is no deduction for the repayment of principal.
Student loans repayments are not considered qualified higher education expenses.The IRS has stated that if you pay for education expenses with money from a loan, you take can use the education expenses in the year you pay the expenses (with the loan proceeds), not in the year you get a student loan or the year you repay the student loan.
