19) Oxytocin

Oxytocin is often touted as the molecule of love, I presume the two bodies in the picture below are a couple. This mighty neuroactive hormone is released in many situations, often ones with emotional content. Being hugged or kissed, breast-feeding, social recognition, anxiety, orgasm, the list goes on. It’s considered by many as the molecule that makes humans want to be social and sociable, that it drives empathy.

Personally I get excited when something as airy fairy as ‘feeling nice’ can be pinned to a chemical structure. It sort of puts things into perspective a bit.