There are many different exercise programs out there.
For the most part, they all work – if you stick with one.
The reason most people don’t see sustained progress in the gym is not because the program doesn’t work.
It’s because they don’t stick to the program.
A good program will lead you to growth, almost indefinitely. At the minimum, for one or two years. But more likely, for several years and beyond.
It’s not a matter of months. It’s a long-term commitment which you must make, first.