Theories surrounding kissing vary – it’s an instinct, a consequence of the way our ancestors fed their children – by chewing the food and then giving it to them. The truth is that it is not clear how we humans started kissing, but we have been kissing for 35,000 years. The first documented instance is found in the Kama Sutra. Nearly 90% of today’s world population practices kissing. What in this act leads to the pleasure we experience in kissing? During this act of closeness and affection, a “mixture” of compounds is created in the brain. This release of adrenaline, dopamine, oxytocin and serotonin leads to the feeling of pleasure, trust, affection. Kissing transmits sensory signals at a subconscious level. Women can even “pick up” a man’s testosterone levels and those of his immune system.