Pheromone Dust

Apparently it was some kind of super-concentrated pheromone that was designed to turn men on, including increasing heart-rate, raise body temperature, and arouse them. It was very amusing seeing Mr. Freeze's reaction to it. Being a scientist himself, he actually recognized the chemicals Ivy was using, which surprised her, and since he had messed up cold chemistry in his body, the pheromone didn't really work on him.

I'm afraid it's more of an example of "comic book fantasy science" at play. They make genetic manipulation or advanced science look so easy for people to play with in Gotham.

There's actually a controversy in the scientific community as to whether humans produce or can react to pheromones or not. Nobody's really sure, nobody can agree whether it's true or not, and nobody's been able to artificially produce a pheromone that can cause reactions in humans that normally drives animals nuts for different reasons.

For example: a male dog smells the pheromones a female dog in heat gives off in her urine, the blood she leaves behind on the ground (yep, girl dogs have periods too, but only in spring time, and if they are not spayed), and what comes off her body in general. A switch turns on in his head, and the male dog has only one thing on his mind: mate with the female. Nothing else will stop him. He must find this female and mate with her. The only thing that could possibly stop him is the female rejecting him, but that doesn't happen a lot, particularly if the female has few choices of partners.

Male human smells the supposed pheromones a woman gives off, but he has to be in close proximity (such as in bed with her), and she can smell whatever supposed pheromones he is producing too. Again, they can choose to ignore it if they want. It'll enhance how they feel during copulation, but the reactions are minor, and they can easily choose to ignore the pheromones or quit.