For years I tried numerous remedies and supplements like chlorophyll, apple cider vinegar and charcoal internally and externally to lessen armpit odor. I don't have bad body odor but it definitely gets worse in the summer when it's humid out. I read on here that caffeine was a big culprit and cut back on it. That helped a bit but what stopped my pits from smelling was simply switching from a teaspoon of organic brown sugar to a teaspoon of xylitol in my morning and afternoon coffee. I wasn't trying xylitol for body odor, I was trying it to keep my blood sugar in the normal range (which it does), so this is an unexpected side effect. I am very pleased.
I hope others will test this and let me know if it's the same for them.