in my experience its not coming from the anus i think its coming from our sweat. I think we have so much bacteria and toxins in our system that when we sweat or get anxious or nervous we start to smell. The instestines must have been damaged from stress, eating unhealthy, and drinking sodas and juices leaving food undigested causing god knows what to grow inside of us. What has helped my odor was going on a healthy Diet : cutting dairy and meat and only drinking water and taking probiotics. im going to try a 5htp supplement and see how that works as well.
Oh and another thing that may help this serotonin claim is that i dont smell at home where i feel comfortable and im not stressing as much but when im out and about and the thought of me smelling gets into my head and i start getting anxious that is when my odor is at its worst. so this disease might be a mental disorder as much as it is physical
shoulda listened to granma when she said quit driking those sodas.