well to me it is both. But I smell the food that I consumed the previous day or two previous days, sometimes if it is meat I can smell it on the palms of my hand. To others it is sometimes like garbage or feces. I do not have Amalgam fillings, and aside from a traditional doctors appointment I have not had any other reason to have needle marks. When I was a kid I got some scrapes and brusies on my body but nothing out of the ordinary. Why do you ask?