Hard to say how fast; I just ground some up since my ground bottle was empty, plan to make pippali milk today. I usually add a couple of good pinches to every hot drink, and that is good. But the boiled down pippali milk is very very effective. Get as much down your throat as you can (within reason) whatever way you can.
I think my lungs are pretty clear after no smoking for almost 14 years.
I do have lots of chronic sinus problems though. I have been using the behind the counter sudafed everyday and even more now since my sinuses are bothering me because of allergies. With just a 1/4 teaspoon of the pepper my sinuses are better.
It works great for constipation too
After I build up to half a teaspoon I’m sure my sinuses will be in great shape with the help from my neti pot.