Scientists have known for decades about an organ just inside the nasal cavity called the vomeronasal organ or VNO, and its sole function is to detect trace amounts of airborne chemicals called pheromones. Pheromones detected by the VNO have been shown in laboratory tests to send powerful signals directly to the limbic region of the brain, also known as the “seat of emotions”. 

This region of the brain is not directly connected to reason or cognitive thought patterns, rather it controls our emotions and sexual desires. So, the stimulating feelings we experience from pheromones can be quite powerful. When these sexual and romantic feelings overwhelm us, our brains release a chemical called phenethylamine which in turn kicks on dopamine production and the next thing we know, the fireworks begin.