Zinc
Essential Trace Mineral
Evidence grade 4 of 5, Strong. Read how the Atlas grades evidence.
Evidence splits by use. For treating deficiency and for childhood acute-diarrhea treatment the evidence is strong (grade 4, approaching 5 for diarrhea): the WHO/UNICEF program rests on a Cochrane review of dozens of RCTs and a large multicenter NEJM trial (Dhingra 2020) showing 20mg/day for 10 to 14 days shortens episodes and lowers diarrhea incidence over the following two to three months. For shortening the common cold the signal is real but modest and formulation-dependent (grade 3): Hemila's individual-patient-data meta-analyses of high-dose ionic zinc acetate lozenges found colds shortened by roughly 2.7 to 2.9 days, but pooled Cochrane estimates carry high heterogeneity, and low-dose or non-ionic formulations show no effect. Zinc's essentiality itself is settled consensus (grade 5) since Prasad's 1960s deficiency work.
- FDA
- Legal supplement (DSHEA)
- WADA
- Not prohibited
Reference only. Not medical advice.
What can go wrong
Safe short-term at label doses; above about 40mg per day chronically it depletes copper and can cause anemia and irreversible neuropathy, and intranasal zinc has caused permanent loss of smell.
Zinc is an essential trace mineral that acts as a cofactor for hundreds of enzymes and is required for immune function, wound healing, and protein synthesis. Correcting a genuine deficiency has real and sometimes large effects, and zinc is a cornerstone of WHO and UNICEF childhood-diarrhea treatment worldwide. For the common cold the story is narrower: high-dose ionic zinc lozenges started within a day of symptoms appear to shorten colds by roughly a day, but the effect is modest, formulation-dependent, and inconsistent across trials. The defining feature of zinc is a narrow window, because chronic doses above about forty milligrams per day deplete copper and can cause serious harm, so more is not better.
A real immune mineral with a narrow window, more is not better.
What people take it for
What it is taken for. Approval, where it exists, covers only some of these.
How it works
Zinc is the second most abundant trace mineral in the human body after iron, with total body content of approximately 2-3 grams distributed across virtually every tissue (highest concentrations in liver, kidney, muscle, bone, prostate, and retina). Its biological importance is extraordinary even relative to other essential minerals: zinc serves as cofactor for over 300 zinc-dependent enzymes spanning every major metabolic pathway (DNA polymerase, alcohol dehydrogenase, carbonic anhydrase, superoxide dismutase, alkaline phosphatase, matrix metalloproteinases), provides structural support for hundreds of "zinc finger" transcription factors that regulate approximately 10% of the human genome, and functions as both intracellular signal and antioxidant. The body has no dedicated zinc storage protein analogous to ferritin for iron, meaning zinc status reflects ongoing intake and absorption rather than long-term reserves, and deficiency develops relatively quickly in inadequate intake states. The immune system is particularly zinc-dependent. Zinc supports T-lymphocyte maturation in the thymus (thymulin requires zinc as cofactor), natural killer cell function, neutrophil chemotaxis and phagocytosis, antibody response, and the maintenance of intact mucosal barriers. The classical zinc deficiency immunology was characterized through acrodermatitis enteropathica (a rare genetic zinc malabsorption disorder identified by Moynahan in 1974) and subsequent zinc-deficient population studies, both demonstrating profound immune dysfunction reversed by supplementation. The common cold mechanism specifically involves zinc binding the ICAM-1 receptor on nasopharyngeal epithelial cells and reducing rhinovirus attachment and replication, the basis for the Eby zinc gluconate lozenge concept and the subsequent forty-year clinical evidence development. Other major zinc-dependent functions span male reproduction (testicular function, sperm count, spermatogenesis), skin and wound healing (keratinocyte function, matrix metalloproteinase activity, collagen synthesis support), bone matrix (alkaline phosphatase activity), retinal function (carbonic anhydrase, retinol dehydrogenase), and taste and smell perception (gustin and carbonic anhydrase VI in taste buds). The breadth of zinc-dependent biology is matched by relatively narrow tolerance, chronic intakes above the 40mg/day Upper Limit can produce copper deficiency, immune suppression, and other concerning effects.
How it is taken
Daily zinc dosing follows established RDAs: 11mg/day for adult men, 8mg/day for adult women (non-pregnant, non-lactating), 11-12mg/day in pregnancy and lactation. Most adults can readily achieve these targets through diet (oysters, beef, pumpkin seeds, beans, fortified cereals); supplemental zinc for general health is reasonable at 15-30mg/day daily, providing modest buffer above RDA without approaching the 40mg/day Upper Limit. The cold lozenge protocol is fundamentally different: zinc gluconate or acetate lozenges (13-23mg elemental zinc per lozenge) every 2-3 hours during waking, starting within 24 hours of cold symptom onset, continued for up to 7 days. Total daily zinc intake during cold protocols can reach 75-130mg, substantially above the chronic Upper Limit but acceptable for short-course (≤7 day) use. AREDS macular degeneration protocol uses 80mg zinc daily with 2mg copper to prevent copper deficiency. Pediatric WHO/UNICEF diarrhea protocol uses 20mg/day for 10-14 days. The critical dosing principles are: (1) form matters (lozenges for colds, chelates for daily, sulfate acceptable for short clinical course), (2) timing matters for cold lozenges (within 24h of symptoms), (3) chronic high doses warrant copper monitoring, and (4) UL for chronic use is 40mg/day.
- RDA adult men
- 11mg/day
- RDA adult women
- 8mg/day
- Pregnancy / lactation
- 11-12mg/day
- Daily supplementation
- 15-30mg/day
- Upper Limit (UL) chronic
- 40mg/day
- Cold lozenge protocol
- 75-130mg/day total, ≤7 days
- AREDS macular degeneration
- 80mg/day with 2mg copper
- Pediatric diarrhea (WHO)
- 20mg/day x 10-14 days
Which form to buy
Not all preparations of the same ingredient are the same thing, and the trials were run on particular ones.
Zinc Gluconate (Cold Lozenges)
The form used in Eby 1984, Mossad 1996, and most positive cold lozenge trials. Zinc gluconate lozenges dissolved slowly in the mouth deliver elemental zinc to nasopharyngeal mucosa where the rhinovirus ICAM-1 interaction occurs. Critical that the dosage form is lozenge (not capsule) and that timing is within 24 hours of symptom onset. Cold-Eeze and similar branded products use this form.
Zinc Acetate Lozenges
Alternative cold lozenge form with substantial clinical evidence (Prasad 2007 and subsequent). Some evidence suggests zinc acetate releases ionized zinc more readily than gluconate at oral pH; clinical effect sizes appear similar across forms. Acceptable alternative to gluconate.
Zinc Bisglycinate / Glycinate (Chelate)
Amino acid chelate form with excellent absorption and minimal GI distress at standard doses. Reasonable choice for daily supplementation in general health contexts. Albion Minerals (now Balchem) holds patents on specific glycinate manufacturing.
Zinc Picolinate
Picolinic acid chelate often marketed for superior absorption versus other forms. Comparative absorption studies (Barrie 1987 and others) show modest absorption advantage; clinical superiority unclear. Reasonable supplementation form.
Zinc Citrate
Common consumer supplement form with good absorption profile and reasonable GI tolerance. Functionally similar to gluconate for absorption; cost-effective option for general supplementation.
Zinc Sulfate
Cheapest form, used historically in clinical contexts and pediatric diarrhea protocols (WHO/UNICEF). Produces more GI distress than chelated forms; less ideal for daily consumer supplementation but acceptable for short-course therapeutic use.
Zinc Oxide
Poor absorption when consumed orally; appropriate for topical use (sunscreen, diaper rash). Sometimes appears in low-cost multivitamin formulations where its bioavailability is suspect. Generally avoid for therapeutic supplementation.
Topical Zinc Pyrithione (Shampoo)
Anti-dandruff and seborrheic dermatitis topical use. Head & Shoulders and similar formulations. Functionally distinct from oral zinc supplementation; topical application targets scalp microbiome (particularly Malassezia).
Who it works for, and who it does not
Common cold (symptom duration reduction)
The Hemilä Cochrane meta-analysis and subsequent reviews support modest cold duration reduction with zinc gluconate or acetate LOZENGES initiated within 24 hours of symptom onset at adequate doses (>75mg elemental zinc daily, divided into lozenges every 2-3 hours during waking). The form, dose, and timing all matter, capsules, oral tablets, and delayed initiation produce minimal effect. Reasonable cold symptom management.
Pediatric acute diarrhea (developing countries)
WHO/UNICEF official recommendation. Zinc supplementation (20mg daily for children 6 months+) for 10-14 days reduces diarrhea duration, severity, and recurrence. Global public health implementation has had substantial mortality impact in low-income settings. Specialist coordination for clinical pediatric use.
Age-related macular degeneration (intermediate or advanced)
AREDS and AREDS2 trials establish zinc as part of the antioxidant formulation reducing progression to advanced AMD. Ophthalmology coordination, not general "eye health" supplement use case. Specific formulation includes vitamins C, E, lutein/zeaxanthin alongside zinc and copper.
Acrodermatitis enteropathica (genetic zinc malabsorption)
Lifelong zinc supplementation required. Genetic disorder of zinc absorption manifesting as severe dermatitis, alopecia, diarrhea, and immune dysfunction. Specialist coordination through medical genetics or dermatology.
Wound healing (deficient or compromised)
Zinc deficiency impairs wound healing; supplementation in deficient cohorts (pressure ulcers, surgical wounds, burns) supports healing. Routine supplementation in non-deficient users does not accelerate wound healing. Clinical context warrants assessment.
Acne vulgaris (moderate)
Modest evidence for oral zinc (zinc gluconate, sulfate, picolinate) at 30-200mg/day in moderate acne. Effect sizes smaller than topical retinoids or oral antibiotics; reasonable adjunctive use particularly in users seeking non-antibiotic approaches. Dermatology coordination reasonable.
Older adults with marginal zinc status
Prasad and others document immune function decline associated with marginal zinc status in older adults. Modest supplementation (15-30mg/day) supports T cell function and reduces infectious disease incidence in zinc-deficient older adults. Routine supplementation in well-nourished older adults shows smaller effects.
Pregnancy (deficient populations)
Modest evidence for zinc supplementation in pregnancy in deficient populations. Most prenatal vitamins include zinc at 15-25mg. Routine high-dose zinc supplementation in pregnancy is not standard practice; coordinate with OB-GYN.
COVID-19 outpatient (mild illness)
Thomas 2021 outpatient trial showed no symptom duration benefit at 50mg/day. Specific inpatient or severe disease contexts may differ but routine outpatient COVID supplementation is not supported. Coordinate with treating clinician for symptomatic illness.
Taken with other things
Combinations people actually use. Evidence for one ingredient is not evidence for a pair.
Copper
Critical pairing at high zinc doses. Zinc and copper compete for absorption; chronic high-dose zinc (>40mg/day) can produce copper deficiency, anemia, and neurological dysfunction. AREDS protocol includes 2mg copper with 80mg zinc; comparable copper supplementation reasonable for chronic high-dose zinc users.
Iron
Both minerals compete for absorption at the intestinal level. Take iron and zinc at separate meals when both are supplemented; clinical interaction is rarely problematic at typical doses but supplementation timing matters for absorption optimization.
Calcium
High-dose calcium supplementation (>1g) reduces zinc absorption. Separate dosing by several hours when both are supplemented. Dietary calcium intake at typical levels does not produce clinically meaningful zinc interference.
Vitamin A (Retinol)
Zinc is required for the conversion of retinol to active retinal forms in the eye. The combination supports retinal function and night vision; clinically relevant in vitamin A deficiency contexts.
Quinolone Antibiotics
Zinc reduces fluoroquinolone (ciprofloxacin, levofloxacin) absorption substantially. Separate dosing by 2-6 hours when on quinolone therapy.
Tetracycline Antibiotics
Similar interaction, zinc reduces tetracycline absorption. Separate dosing by 2-6 hours.
ACE Inhibitors and Thiazide Diuretics
Some ACE inhibitors and thiazide diuretics increase urinary zinc excretion. Long-term users may have modestly increased zinc requirements; coordinate with prescribing physician.
Vitamin C (High-Dose)
Combined for cold symptom management. Mechanistically complementary, zinc for direct viral inhibition, vitamin C for immune support and modest cold duration reduction. The Thomas 2021 trial tested high-dose combination for COVID-19 (negative outcome) but the cold context retains moderate evidence base.
What to look for on the label
Look for: USP or NSF third-party verification on label; specific zinc compound disclosed (gluconate, acetate, bisglycinate, picolinate, citrate); elemental zinc content clearly stated (not just compound weight); copper inclusion at appropriate ratio (1:5 to 1:15) for chronic high-dose products; lozenge-specific formulation for cold lozenges (not just zinc capsules marketed as lozenges); reasonable price per mg elemental zinc. Avoid: zinc oxide as primary form in oral supplements (poor absorption); proprietary "immune blends" obscuring zinc dose; very high-dose chronic supplementation (>50mg daily) without copper inclusion; cold lozenges with citric acid or strong flavoring that may chelate zinc; products from manufacturers without third-party testing disclosure.
Safety in detail
- Generally well-tolerated at standard supplementation doses (15-30mg/day daily). Higher doses (75-130mg/day during cold protocols) acceptable for short-course (≤7 day) use; chronic high-dose intake produces concerns.
- GI upset (nausea, vomiting, abdominal pain) is the most common acute side effect, particularly with zinc sulfate and at high single doses. Taking with food reduces GI sensitivity; chelated forms (bisglycinate, picolinate, citrate) are generally better tolerated.
- Metallic taste from zinc lozenges is dose-related; common during cold protocols and generally well-tolerated.
- Copper deficiency is the most important chronic high-dose concern. Zinc intakes above 40mg/day for extended periods can produce copper deficiency manifesting as anemia, neutropenia, and (in severe cases) neurological dysfunction. Chronic high-dose users should include copper supplementation (~2mg per 80mg zinc).
- Immune suppression at very high doses, paradoxically, extremely high zinc intakes can suppress immune function (the opposite of marginal-status supplementation effects).
- HDL cholesterol reduction at high doses; clinical significance modest.
- Pregnancy and lactation: standard prenatal levels (15-25mg) are safe and routine. High-dose zinc supplementation in pregnancy outside specialist guidance not recommended.
- Pediatric use: WHO/UNICEF protocol established for diarrhea; routine pediatric supplementation in non-deficient children not necessary.
- Long-term safety at typical supplementation doses (15-30mg/day) is excellent. The copper deficiency concern at chronic doses >40mg/day is the meaningful limitation.
What people get wrong
Often saidZinc supplements prevent colds.
ActuallyThey do not prevent colds reliably. The evidence supports zinc LOZENGES (not capsules) reducing cold DURATION when initiated within 24 hours of symptom onset. Prevention evidence is much weaker; symptom-onset intervention is the established use case.
Often saidAny zinc form works for colds.
ActuallyThe form matters substantially. Lozenges (zinc gluconate or acetate) that dissolve slowly in the mouth deliver zinc to nasopharyngeal mucosa where the rhinovirus interaction occurs. Capsules and tablets bypass this delivery and produce minimal cold benefit.
Often saidHigher zinc doses always produce better results.
ActuallyDiminishing returns set in. Chronic intake above 40mg/day produces copper deficiency and immune suppression. Cold lozenge protocols use higher daily totals for short courses; this is acceptable short-term but not for chronic use.
Often saidZinc cures or prevents COVID-19.
ActuallyThe Thomas 2021 outpatient trial showed no symptom duration benefit at 50mg/day. Mechanism is plausible; clinical translation in outpatient mild illness is negative. Severe disease and inpatient contexts may differ but routine outpatient supplementation is not supported.
Often saidVegetarians need much more zinc than meat eaters.
ActuallyBioavailability is modestly lower from plant sources (phytate inhibition) but typical vegetarian diets with adequate legume and whole grain intake achieve adequate zinc status. Targeted supplementation may be reasonable for strict vegan athletes; routine 2-3x RDA recommendations are excessive.
Often saidZinc oxide in supplements is well-absorbed.
ActuallyIt is not. Zinc oxide has poor oral bioavailability compared to chelated forms. Zinc oxide is appropriate for topical use (sunscreen, diaper rash) but generally avoid as oral supplementation primary form.
Often saidYou can take any amount of zinc as long as you take copper too.
ActuallyEven with copper supplementation, very high zinc doses (>100mg/day chronic) can produce health concerns beyond just copper status. The 40mg/day Upper Limit applies for chronic use; short-course cold protocols can exceed this acceptably.
Who profits, and who pushes back
Ananda Prasad
Foundational figure in zinc nutrition research, characterizing first human zinc deficiency syndrome and conducting decades of subsequent zinc supplementation research including the 2007 cold acetate trial. Independent academic; foundational scientific contribution.
George Eby
Initiated zinc gluconate cold lozenge research with the 1984 trial conducted essentially as citizen science. Substantial commercial implications followed; Eby remained independent of supplement industry profits.
Harri Hemilä
Lead author of Cochrane systematic reviews on zinc for common cold. Among the most authoritative voices on the cold supplementation evidence base. Independent academic.
WHO/UNICEF
Official recommending bodies for zinc supplementation in pediatric diarrhea management in developing countries. Implementation has had substantial mortality impact globally.
NIH National Eye Institute
Sponsor of the AREDS and AREDS2 trials that established the macular degeneration formulation. Substantial independent research investment.
Cold lozenge industry (Cold-Eeze, Zicam, generics)
Sells this. Has a commercial interest in a product sold as this compound, as of July 2026.
Substantial commercial interest in the cold lozenge category. Marketing has generally aligned with evidence base; Zicam specifically faced FDA warning in 2009 about intranasal zinc spray (loss of smell) but oral lozenge category remains evidence-supported.
Recent Cochrane reviewers
Recent Cochrane updates have been more cautious about zinc lozenge effect-size certainty than earlier reviews. The duration-reduction effect appears real but smaller than originally estimated; trial heterogeneity is substantial. Consumer marketing of "zinc cuts cold time in half" exceeds what current evidence supports, modest duration reduction is the realistic expectation.
Mainstream infectious disease
The early COVID-19 enthusiasm for zinc supplementation based on observational correlations and mechanistic plausibility was substantially constrained by Thomas 2021 outpatient trial showing no symptom duration benefit. The mechanism-translation gap (M-09) is relevant: zinc-rhinovirus mechanism is established; COVID-19 outpatient clinical translation was not. Consumer guidance should engage with the negative trial rather than continue mechanistic speculation.
How we got here
Zinc's essentiality in human nutrition was established remarkably late in nutritional science history. The first human zinc deficiency syndrome was characterized in 1961 by Ananda Prasad working with adolescent Iranian and Egyptian patients with growth retardation, hypogonadism, and other manifestations responsive to zinc supplementation. This established zinc essentiality and inaugurated decades of zinc research that would establish the breadth of zinc-dependent biology. Acrodermatitis enteropathica, a rare genetic disorder of zinc malabsorption, was characterized by Moynahan in 1974, with the dramatic reversal of severe dermatitis, alopecia, and immune dysfunction by oral zinc supplementation providing additional foundational evidence for zinc essentiality. The common cold zinc story began in 1984 with George Eby's placebo-controlled trial of zinc gluconate lozenges, conducted essentially as citizen science, Eby was a city planner whose daughter's cold improved dramatically when she sucked zinc gluconate lozenges. The publication catalyzed decades of subsequent research. The 1996 Mossad Cleveland Clinic trial in the Annals of Internal Medicine established clinical-grade evidence; the 2007 Prasad zinc acetate trial extended the form options; the Hemilä Cochrane meta-analyses (2011-2017 cycles) consolidated the duration-reduction evidence. The consumer cold lozenge category (Cold-Eeze launched 1994, Zicam launched 1999, multiple generic store brands) built substantial commercial scale around the evidence. The pediatric diarrhea story developed in parallel through international health research. The 1988 Castillo-Durán trial in Chilean children established the diarrhea duration reduction effect; subsequent work in Bangladesh, India, and other low-income settings confirmed substantial mortality benefit. The 2004 WHO/UNICEF formal recommendation institutionalized zinc supplementation as standard pediatric diarrhea management globally, among the highest-impact applications of nutritional supplementation in modern public health. The macular degeneration evidence developed through the NIH National Eye Institute AREDS trial (Age-Related Eye Disease Study), a large randomized trial that established the antioxidant + zinc + copper formulation reducing AMD progression. AREDS2 (2013) refined the formulation by replacing beta-carotene with lutein and zeaxanthin (after smokers showed elevated lung cancer risk in the original AREDS beta-carotene group). The PreserVision branded formulation and generic AREDS-compliant products represent substantial ophthalmic commerce. The COVID-19 era brought substantial new attention to zinc supplementation. Early functional medicine guidance heavily emphasized zinc; observational studies suggested correlation between zinc status and COVID outcomes; mechanistic work on zinc and SARS-CoV-2 replication generated optimism. The 2021 Thomas JAMA Network Open outpatient trial showed no symptom duration benefit at 50mg/day in mild outpatient illness. Subsequent work has not established a clear clinical role for zinc supplementation in COVID-19 management. The story illustrates the gap between mechanistic plausibility and clinical outcomes.
- 1961Prasad characterizes first human zinc deficiency syndrome (Iran/Egypt)
- 1974Moynahan characterizes acrodermatitis enteropathica reversal
- 1984Eby first zinc gluconate cold lozenge trial
- 1988Castillo-Durán pediatric diarrhea trial (Chile)
- 1994Cold-Eeze launches; consumer cold lozenge category established
- 1996Mossad Cleveland Clinic cold trial (Ann Intern Med)
- 1999Zicam launches zinc acetate cold products
- 2001AREDS macular degeneration formulation established
- 2004WHO/UNICEF formal pediatric zinc diarrhea recommendation
- 2007Prasad zinc acetate cold trial
- 2013AREDS2 reformulation; Hemilä Cochrane positive review
- 2020-21COVID-19 zinc supplementation interest peaks; Thomas trial negative
What we do not know
- Whether zinc lozenge cold benefits will be more or less certain in updated Cochrane analyses, recent reviews have been more cautious about effect-size certainty than earlier positive reviews.
- Whether specific cold lozenge forms (gluconate vs acetate) produce meaningfully different clinical outcomes in head-to-head trials.
- Whether zinc supplementation has applications in COVID-19 or post-acute COVID contexts beyond the negative outpatient evidence, inpatient and specific phase research continues.
- How best to identify users with marginal zinc status who would benefit most from supplementation (no widely-validated clinical zinc status marker; plasma zinc is insensitive).
- Whether the AREDS macular degeneration formulation needs refinement based on more recent evidence (AREDS2 already reduced beta-carotene to lutein/zeaxanthin; further updates pending).
- Whether zinc has applications in skin conditions beyond moderate acne, preliminary evidence in rosacea, atopic dermatitis, and other inflammatory skin conditions.
- Long-term zinc status in chronic ACE inhibitor and thiazide diuretic users, whether routine supplementation should be considered.
- Whether zinc transporter polymorphisms (SLC30A8 and others) modulate individual zinc supplementation response, pharmacogenomic considerations emerging.
Legal status
Universally available globally as dietary supplement, food fortification, and pharmaceutical product. Legal under DSHEA in the United States and equivalent regulations globally. Not on WADA prohibited list. Pharmaceutical zinc preparations are used in clinical contexts (acrodermatitis enteropathica, hemodialysis patients, severe deficiency). The cold lozenge category (Cold-Eeze, Zicam, Cold Calm, generic store brands) is widely accessible OTC. AREDS-formulation eye health products (PreserVision and others) are widely available. WHO/UNICEF zinc supplementation programs distribute pediatric zinc in low-income settings as part of integrated diarrhea management. Major brands include Nature's Bounty, NOW Foods, Thorne, Pure Encapsulations, Solgar, and most multivitamin manufacturers. Production from zinc ore through pharmaceutical-grade purification is well-established at commodity pricing.
Status current as of July 2026. Regulatory positions change, sometimes quickly.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Zinc supplement production starts from zinc ore (sphalerite is the dominant zinc mineral) processed to high-purity zinc through hydrometallurgical or pyrometallurgical refining. Pharmaceutical-grade zinc compounds are produced through controlled reaction with the relevant counter-anion (gluconate, picolinate, citrate, etc.). Chelated forms (bisglycinate, picolinate) involve specific chelation chemistry with intellectual property considerations, Albion Minerals (now Balchem) holds patents on specific glycinate manufacturing methods. Quality variation across brands is modest given the well-established chemistry; third-party testing (USP, NSF, Informed Sport) provides standard verification. The cold lozenge category specifically requires careful formulation, the lozenge must release ionized zinc at physiological pH for the ICAM-1 binding mechanism; certain flavoring agents and citric acid can chelate zinc and reduce free zinc availability. Cold-Eeze, Zicam (zinc acetate), and licensed pharmaceutical lozenges generally have appropriate formulation; some generic lozenges may have less optimal release characteristics.
At a glance
- Status
- Essential trace mineral
- Total body content
- 2-3 grams
- Dependent enzymes
- >300 (the "zincome")
- Zinc finger proteins
- Regulate ~10% of human genome
- RDA adult men
- 11mg/day
- RDA adult women
- 8mg/day
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Zinc. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
- Where we land. We have not taken a position on this yet.
Sources
Zinc acetate lozenges shortened colds by about 2.7 to 2.9 days in individual-patient-data meta-analysis of high-dose ionic zinc trials
Zinc acetate vs gluconate and role of dose; mean cold duration 33 to 40 percent shorter with zinc, dose above 75mg per day needed
WHO recommends 20mg per day zinc for 10 to 14 days for childhood diarrhea (10mg under six months); shortens duration and lowers incidence over following two to three months
Lower-dose zinc noninferior for childhood diarrhea with less vomiting; large multicenter randomized trial
Cochrane review supports oral zinc for treating childhood diarrhea
RDA 11mg men / 8mg women, adult UL 40mg per day; forms gluconate/acetate/sulfate; doses of 50mg+ for weeks interfere with copper absorption; cold reduces duration not severity; diarrhea shortened about half a day
NIH Office of Dietary Supplements, Zinc fact sheet for health professionals
FDA warned consumers to stop using three Zicam intranasal zinc products after more than 130 anosmia reports; warning letter to Matrixx Initiatives in June 2009
Zinc-containing denture adhesive as a source of excess zinc causing copper-deficiency myelopathy
Zinc-induced copper deficiency presenting with anemia, sensory ataxia and cognitive impairment from zinc-containing dental adhesive
Role of zinc in pediatric diarrhea; mechanism and evidence base overview
The studies that matter
Moynahan acrodermatitis enteropathicaLancet 1974
Foundational characterization of the genetic zinc malabsorption disorder and its reversal with zinc supplementation. Established zinc essentiality in human nutrition and the immunological consequences of deficiency.
Eby et al. zinc gluconate cold lozenge trialAntimicrob Agents Chemother 1984
First placebo-controlled trial of zinc gluconate lozenges for common cold symptom reduction. Foundational work that launched four decades of zinc-cold research and consumer lozenge category.
Mossad et al. zinc gluconate Cleveland Clinic trialAnn Intern Med 1996
Positive RCT in Cleveland Clinic employees: zinc gluconate lozenges (initiated within 24 hours of symptom onset) reduced cold duration by approximately 3 days versus placebo. Established the clinical-grade evidence for cold lozenge use case.
Prasad et al. cold trialJ Infect Dis 2007
Comprehensive RCT supporting zinc acetate lozenge efficacy for cold symptom duration and severity reduction. Helped establish the dose-frequency relationship (every 2-3 hours during waking).
AREDS macular degeneration trialArch Ophthalmol 2001
Large NIH National Eye Institute trial: antioxidant formulation including zinc (80mg/day plus copper) reduced progression to advanced age-related macular degeneration in moderate-risk patients. Foundational ophthalmic evidence; AREDS2 (2013) refined the formulation.
Castillo-Durán pediatric diarrheaJ Pediatr 1988
Foundational pediatric trial demonstrating zinc supplementation reduced acute diarrhea duration in developing-country children. Established the WHO/UNICEF zinc-diarrhea pediatric protocol that has saved hundreds of thousands of lives globally.
Hemilä Cochrane cold meta-analysisCochrane Database 2013, updates
Cochrane systematic review of zinc lozenge trials for common cold: positive effect on duration when zinc gluconate or acetate lozenges initiated within 24 hours of symptom onset at adequate doses. Subsequent updates have been more cautious about effect-size certainty.
Thomas COVID-19 ascorbic acid + zinc trialJAMA Netw Open 2021
Large outpatient COVID-19 RCT: zinc 50mg + vitamin C 8000mg did not reduce symptom duration versus placebo. Established the negative COVID symptom evidence at outpatient mild illness; does not address inpatient or severe disease contexts.
Prasad zinc-immunity and agingMol Med 2008
Comprehensive review establishing zinc supplementation benefits in older adults with marginal zinc status, improvements in T cell function, infectious disease incidence, oxidative stress markers. Foundational geriatric immunology evidence.
WHO/UNICEF zinc diarrhea recommendation2004 official guidance
Following decades of evidence including Castillo-Durán and meta-analyses, WHO and UNICEF formalized zinc supplementation as standard pediatric diarrhea management in developing countries. Global public health implementation has had substantial mortality impact.