One teaspoon of cayenne pepper dissolved in fresh squeezed lemon juice w/ a pinch of REAL Sea Salt (celtic or himalayan [can get at whole foods]).
Drink lemon water everyday with a pinch of Sea Salt .
This works for me - not a cold nor a cough nor flu for about 3 years now...
I did however make other general adjustments so maybe the combination has worked. (ie: no dairy, White Sugar , lots of water, greens and fruits, etc etc etc...)
Maybe it will work for you?
Also add cayenne to broths and soups - yumm.
I use regular cayenne from the market - McCormicks mostly, other brands if necessary. They also have 'organic'.