With One Main Financial they have no minimum required credit score to get you approved for a One Main Financial loan.
I got approved for a One Main Financial Loan with a credit score of 600 so I do know that if your credit score is at least 600 then you'll likely get approved for a loan through them.
However they might also approve loans with a lower credit score but I can't say for sure.
Most people who get approved for a One Main Financial Loan have Credit Scores between 600 and 650/
One Main Financial has actually improved my credit score since I paid the One Main Financial loan on time and never missed payments.
So now I can get loans much easier at other banks and places as well.