When I use it, my nose opens up completely and I can breath great. The
effect lasts for about 6 hours and after that my nose gets congested again.
After some research online, I think that what is happening is that the spray causes the blood vessels to shrink, opening up my nose passage, and after the effect is gone the blood vessels swell up.
Other than that, I haven't had any other side effects.
I have also used saline spays, but they don't seem to help.