@robmandu Are you kidding? Zicam is a homeopathic remedy (i.e., no active ingredients) and has been targeted by consumer fraud groups. Zicam sued.
My experience with the common cold these past six decades is that each one has a slightly different profile of symptoms and durations. Some simply linger longer than others, all other things (such as your immune system) being equal. Just ride it out and be thankful it’s self-limited and not life-threatening.
“With treatment a cold should disappear in about 14 days; without treatment it may linger as long as two weeks.”—ancient wisdom
Hope is on the horizon. Recent research may have uncovered antigens that are commonly shared by all rhinoviruses (the usual surface antigens are unique for each), leading to a possible pathway to a one-time vaccine against all strains of the common cold. Wait a few years…