Is there a way to reduce propionic acid, or sweat smelling like vinegar?

Body odor. Body odor is caused by the bacteria breakdown of sweat. Most medications cause the reduction of sweat. There is over the counter topical certaindri, topical prescription drysol and 3% topical glycopyrrolate. There is the oral medication Robinul but there are side effects. Also Botox injections reduce sweat. One can treat the bacteria by topical antibiotics. See you local dermatologist for help.
Sweat odor. If over-the-counter antiperspirants don't help control your sweating, your doctor may prescribe aluminum chloride (drysol, xerac ac). For best results, apply the antiperspirant at night to the areas most prone to sweating. Prescription antiperspirants are strong solutions that can cause red, swollen and itchy skin in some people. If irritation develops, wash the medication off in the morning.