It's not that fast, and definitely not instant. Personally I've used quick start, stability and tetra safe start, and I've found that tetra safe start was the only one that sped up the cycle considerably. But the absolute fastest method to cycle a tank is to use filter media from an already established tank.
Regardless of which method you choose, you will need a source of ammonia to get the cycle going, and your water won't be safe for animals until you get a nitrate reading, but no ammonia or nitrites. Hope this helps!