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What is the truth behind the effectiveness of Cold-EEZE (http://www.coldeeze.com/)? The product claims to be homephathic (which is a pseudo-science) but there seems to be actual, evidence-based support in favor of its effectiveness. Here is a research paper supporting Cold-EEZE. In particular, this papers claims that zinc gluconate glycine lozenges (active ingredient of Cold-EEZE) reduces the occurence and the duration of common cold.
I am skeptical of both the medicine and the paper supporting it. The medicine claims to be homeopathic. Although homeopathy is pseudo-science, the medicine does not seem to be homeopathic, it's only diluted twice, something sounds fishy to me. I think they are advertising as homeopathy but it is not actual homeopathy. Moreover, the paper seems to force the result.
In short, can someone please explain me whether zinc gluconate glycine lozenges, and specifically Cold-EEZE is effective against common cold. Please support your claim with evidence. Although I'm very skeptical against this product, my friend seems to be believe in its effectiveness, therefore every claim must be supported by scientific facts to convince my friend, too.