Sex pheromones are hormonal chemicals created by the bodies of humans and other mammals, insects and many other living creatures. Their purpose is to transmit information to other individuals of the same species. Generally, in humans, our pheromones cause an attraction towards the opposite sex. Heard of the "scent of a woman?" That scent is her pheromones talking to your brain.
Ok, actually, that's a bit of an exaggeration. While sex pheromones are received by our olfactory organ (that's your nose), they don't actually have a noticeable scent or odor. There have been lots of claims that by adding human sex pheromones to colognes or perfumes, you can become irresistible to the opposite sex. This is based on the idea that sex pheromones in some organisms are released by the female when she's ripe for mating. However, scientists have been unable to determine exactly what the human sexual response is to sex pheromones. Some studies have shown that men using cologne with sex pheromones got more action than men using a placebo cologne, but more studies are needed in order to have conclusive evidence.
So, if you're looking for an easy way to meet the ladies, a sex pheromone laden cologne probably isn't going to draw the women in like flies to honey, but it doesn't hurt to give it a shot, right? Remember though, that the sense of smell is a very powerful sexual trigger. You'll probably attract just as many women by making sure that you've showered and not put on too much cologne.