Through three smell layers that waft from the skin, human bodies constantly convey information associated with their own health, age, emotional state and more. Underneath sweat odors and dietary influences, each person emanates a unique baseline smell that’s much like a signature or fingerprint which is defined by our major histocompatibility complex (MHC) genome. This is often pivotal in attraction. Further, fluctuations in one’s baseline smell can indicate a great deal—including the shift of emotions and the onset illness. The latter is why certain diseases (including Covid-19) can be diagnosed through smell by a trained doctor or with the assistance of a dog. Read more about the way scent molecules work and how we interpret them at the Wall Street Journal.
Image by Brian Gill