I struggled with Body Odor too. But now a days, I hardly ever have a problem. I figured out I had a twofold reason for smelly armpits -
First, my BO seemed worse when I did not eat enough protein. When I upped my protein intake, it became better.
Second, I found it was my clothes, rather than me, that smelled. I sprayed 90% alcohol under the armpits of my shirts, let it dry and gave it a wash. No more smelly armpit-clothing.
I also use castor oil and rosewood essential oil under my armpits. Most days now I do not use deoderant, except when I know I have strenious activity coming.
Also try rinsing your armpits with a weak water + vinigar mix after a shower.
Be carefull of the anti-bacterial soap. Your body naturally has bactieria - good ones and bad ones - , and if you kill off everything, the bad guys take over...
So get yourself a nice gentle glycerin soap, or even better, make your own soap.