See post #28, then consider external (or more accurately internal) sources.
The old adage is "you are what you eat." And drink.
Cutting fats and sugar from your diet and carbs where possible may help. Additionally red meat can make a difference. In Asia residents say that can smell an American meat diet.
Secondly, do you take supplements. Those can really make for a funk, as can some prescription medicines. Some herbal teas can do the same as well as cause staining sweat.
It is worth a try.