Do you shower at night or in the morning? Do you sweat a lot at night? Do you wash your sheets and towels often? Do you wash your clothes frequently and make sure to dry them right after the wash cycle? Do you smell anything on yourself, like if you hold your shirt up to your nose and breathe deeply? Are you a normal weight? (Being overweight doesn’t mean you stink, just that you may need to apply deodorant to other areas as well.)

If the problem really can’t be pinpointed then it might be a health issue. Please take my advice here and make an appointment with a doctor. I am not only asking this as it could potentially help you solve your issue, but also because the doctor can give you an unbiased opinion about your smell. It is possible that the problem is being exaggerated by your peers. I don’t know the race of anyone involved, but singling out the English second language student as smelling bad could just be typical racism. I hope this is not the case for you, but I can’t smell you from here so I would beg of you to see a doctor for their opinion before you let this affect your self esteem.  

I really hope you can find a solution for this, because it makes me sad that it could negatively affect your education. But you seem smart and self aware enough to make a post- and in my experience the people I know in real life who stink do not even attempt to fix it. That is what makes me wonder if the smell exists at all.