Pheremones = a.k.a. a chemical odor that can attract the opposite sex
This is a tough debate but for me it's easy: They don't exist. Why? For the fact that there isn't much evidence.
I'm not saying that they certainly 100% don't exist. But to the point where we can actually use them or market them, no.
But the same with ghosts and UFO's, there just isn't enough positive evidence to support it, and by scientific standards (the same standards we use to judge the effectiveness of almost everything) pheromones are just not provable because they aren't falsifiable in any way.
Also, placebo effect.