How Human Pheromones Work to Attract the Opposite Sex Pheromones are odors that are produced and secreted by one individual and detected by another individual of the same species. Studies, experiments and research indicates that human pheromone signals are detected through an auxiliary olfactory sense organ 3 inches inside the nose called the Vomeronasal Organ or VNO for short. When the Vomeronasal Organ detects pheromones such as androstenone, it sends sexual response signals to the brain. This creates an attraction between two individuals of the same species. Since the communication between the VNO and pheromones cannot be sensed by the 5 senses of the human body, the VNO is often called the "sixth sense".