It's Ethephon and if your plants a male it's a male. You can get it to suppress male inflorescences using ethephon but it's not going to make a male into a plant worth growing if you're looking for harvestable bud.
Just wait until you're sure what sex it is. You have plenty of time. If they're male then either turn them into compost or collect pollen for making seeds and then turn into compost.
The reversal spray most people use is Florel because it's easy to get. It's been sold for a long time for other uses. There are some that spray it on female plants that hermie. While it may stop any further formation some would not smoke a plant sprayed with it.
Bottom line is that if you're growing regular seeds and not feminized no spray is going to be of any use if you have a true male plant.