For non medical causes of BO..... It's "Antiperspirant-deodorant" not "deodorantI ". Check the packet, deod doesn't stop you sweating. Lots of people don't seem to know the difference - but if there are wet patches under your arms, then you are probably not using Antiperspirant.
And wash your clothes, at 40deg minimum so that bacteria are actually killed. And then dry them properly!
I have a really sensitive nose (I always can detect "off" food, lots of strong smell make me feel sick), and I am amazed at the number of CLEAN people wearing DIRTY clothes - I can smell the clean person underneath, and the musty clothes on top (maybe I was a dog in a previous life?)!
I knew someone who REALLY stank - of fish, it happened over the course of a few days - they had a bacterial infection, and once treated they were no more smelly than anyone else.
Lots of people just don't wash and it's DISGUSTING that I can smell walk past someone and smell shit, piss, semen
(oh god it's rank smelling that on someones hand in the street), on the "unwashed" - the sweat is the least of it (did I mention I may have been a dog in a previous life
?).