(frequently

zinc acetate Zinc acetate is a salt with the formula Zn(CH3CO2)2, which commonly occurs as the dihydrate Zn(CH3CO2)2·2H2O. Both the hydrate and the anhydrous forms are colorless solids that are used as dietary supplements. When used as a food additive, it ha ...

zinc gluconate Zinc gluconate is the zinc salt of gluconic acid. It is an ionic compound consisting of two anions of gluconate for each zinc(II) cation. Zinc gluconate is a popular form for the delivery of zinc as a dietary supplement providing 14.35% eleme ...

lozenge Lozenge or losange may refer to: * Lozenge (shape), a type of rhombus *Throat lozenge, a tablet intended to be dissolved slowly in the mouth to suppress throat ailments *Lozenge (heraldry), a diamond-shaped object that can be placed on the field of ...

s) are a group of dietary supplements that are commonly used for the treatment of the . The use of zinc supplements at doses in excess of 75 mg/day within 24 hours of the onset of symptoms has been shown to reduce the duration of cold symptoms by about 1 day in adults. Adverse effects with zinc supplements

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

include bad taste and

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

. The intranasal use of zinc-containing

nasal spray Nasal sprays are used to deliver medications locally in the nasal cavities or systemically. They are used locally for conditions such as nasal congestion and allergic rhinitis. In some situations, the nasal delivery route is preferred for syst ...

s has been associated with the loss of the sense of smell; consequently, in June 2009, the

United States Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...

(USFDA) warned consumers to stop using intranasal zinc. The

human rhinovirus The rhinovirus (from the grc, ῥίς, rhis "nose", , romanized: "of the nose", and the la, vīrus) is the most common viral infectious agent in humans and is the predominant cause of the common cold. Rhinovirus infection proliferates in tem ...

– the most common viral pathogen in humans – is the predominant cause of the common cold. The hypothesized

mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targ ...

by which zinc reduces the severity and/or duration of cold symptoms is the suppression of nasal

inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...

and the direct inhibition of rhinoviral receptor binding and rhinoviral replication in the

nasal mucosa The nasal mucosa lines the nasal cavity. It is part of the respiratory mucosa, the mucous membrane lining the respiratory tract. The nasal mucosa is intimately adherent to the periosteum or perichondrium of the nasal conchae. It is continuous w ...

Effectiveness

A 2016 meta-analysis on zinc acetate-lozenges and the common cold in 199 patients found that colds were 2.7 days shorter by zinc lozenge usage. This estimate is to be compared with the 7 day average duration of colds in the three trials. A 2015 meta-analysis on zinc lozenges and the common cold found no difference in the effects of zinc acetate lozenges on diverse respiratory symptoms. Although zinc lozenges most probably lead to highest concentration of zinc in the pharyngeal region, a subsequent meta-analysis showed that the effects of high-dose zinc acetate lozenges did not significantly differ in their effects on pharyngeal and nasal symptoms. The duration of nasal discharge was shortened by 34%, nasal congestion by 37%, sneezing by 22%, scratchy throat by 33%, sore throat by 18%, hoarseness by 43%, and cough by 46%. Zinc lozenges shortened the duration of muscle ache by 54%, but there was no significant effect on the duration of headache and fever. A 2013 review which said that zinc supplementation might be helpful for the common cold was withdrawn by the

Cochrane Collaboration Cochrane (previously known as the Cochrane Collaboration) is a British international charitable organisation formed to organise medical research findings to facilitate evidence-based choices about health interventions involving health profess ...

over concerns about the data used.

Interactions

Some lozenge formulations do not contain enough zinc to effectively reduce the lengths of colds; some of them contain ingredients that bind zinc, like

citric acid Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in ...

, which prevent the zinc from working.

Safety

There have been several cases of people using zinc

s and suffering a loss of sense of smell. In 2009 the US

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

issued a warning that people should not use nasal sprays containing zinc. Excessive zinc intake may result in an unpleasant taste and/or

Mechanism of action

The hypothesized

by which zinc reduces the severity and/or duration of cold symptoms is the suppression of nasal

and the direct inhibition of rhinoviral receptor binding and rhinoviral replication in the

. Zinc has been known for many years to have an effect on cold viruses in the laboratory. In the

arteriviridae ''Arteriviridae'' is a family of enveloped, positive-strand RNA viruses in the order ''Nidovirales'' which infect vertebrates. Host organisms include equids, pigs, Possums, nonhuman primates, and rodents. The family includes, for example, equ ...

and

coronaviridae ''Coronaviridae'' is a family of enveloped, positive-strand RNA viruses which infect amphibians, birds, and mammals. The group includes the subfamilies '' Letovirinae'' and ''Orthocoronavirinae;'' the members of the latter are known as coronavi ...

families of virus that also cause the common cold,

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called " test-tube experiments", these studies in biology ...

studies found that zinc

ionophore In chemistry, an ionophore () is a chemical species that reversibly binds ions. Many ionophores are lipid-soluble entities that transport ions across the cell membrane. Ionophores catalyze ion transport across hydrophobic membranes, such as liq ...

s block the replication of those viruses in cell culture.

References

{{reflist Medical treatments Zinc Common cold