There are a number of things to consider before cosigning a loan:
Hard credit check: Beyond the temporary impact on your credit score from the hard credit check during the application, cosigning a loan can hurt your credit in a few different ways:
Additional responsibility: Even though the borrower is in charge of making timely payments on the loan, the cosigner is still technically responsible, too. If the borrower misses a payment, their credit score could drop and so could the cosigner’s.
Potential for default: Enough missed payments could cause your loan to go into default and possibly collections. That means you’ll owe the balance in full. It not only causes your credit score to tank but severely hurts your chances of getting approved for other credit opportunities in the future.