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Zn9.0
Zinc Research
Likely helpsHigh safety
43 peer-reviewed studies
What the evidence says
Likely helps
Zinc appears to help in 18 of 24 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1996–2026 with a typical study size of 1,076 participants.
Based on 43 studies · 31 meta-analyses · 2 RCTs · 488,790 total participants
Confidence
High
What the studies found
18helped6unclear· 19 more without graded effect data
Sleep & insomniaImproved sleep quality · 2-4 weeks · Zinc status linked to sleep quality and duration · 2-4 weeks
Too few graded studies1 study
By the numbers
Pulled from 37 studies with measurable effects
Likely real effects
88%
across studies
People studied
489k
typical study: 1076 people
Strongest designs
33
31 pooled, 2 randomised
Showed benefit
75%
18/24 studies
How long studies ran
1–3 months
3
3+ months
1
Populations Studied
Adults4
General population2
Various populations2
Individuals in malaria-endemic areas1
Active research area
25 studies in the last 5 years · Latest meta-analysis: 2026
199620112026
1Risk of malaria parasitaemiaMeta-AnalysisCited 5×n=1,339 · large study2023
Further research with larger sample sizes is warranted to explore the potential effects of multi-nutrient supplementation and to identify more specific micronutrients and additional factors associated with the risk of malaria, rather than just zinc alone, among individuals in different malaria-endemic areas.
Kotepui M et al. · Nutrients (2023)
No clear effect
← WorseNo effectBetter →
Could be chance
The effect sizes, represented as risk ratios (RRs) with 95% confidence intervals (CIs), were standardised by transforming them into log RRs and then pooling them using a fixed-effects or random-effects model depending on the heterogeneity across studies.
The meta-analysis revealed that zinc supplementation alone did not significantly affect the risk of malaria parasitaemia compared with placebo (p = 0.30, log RR = 0.05, 95% CI: -0.05-0.15, I2 = 0.00%, with 566 malaria cases in the zinc intake group and 521 malaria cases in the placebo group).
The findings of this systematic review indicate that zinc supplementation, either alone or combined with the supplementation of other micronutrients such as vitamin A, iron, or multiple nutrients, does not significantly alter the risk of malaria parasitaemia.
2Lipid profile improvementMeta-AnalysisCited 14×n=1,067 · large study2023
Significant improvement was observed in all 4 lipid profile components.
Heidari Seyedmahalleh M et al. · Advances in nutrition (Bethesda, Md.) (2023)
Noticeable benefit
← WorseNo effectBetter →
Likely real
Significant improvement was observed in all 4 lipid profile components.
Following zinc supplementation, a significant decrease was observed in TC (weighted mean difference [WMD]: -16.16; 95% confidence interval [CI]: -26.43, -5.89; P = 0.002), LDL (WMD: -6.18; 95% CI: -9.35, -3.02; P < 0.001), and TG (WMD: -13.08; 95% CI: -21.83, -4.34; P = 0.003).
After analyzing 13 studies reporting HDL, a significant increase was seen (WMD: 3.76; 95% CI: 1.30, 6.22; P = 0.003).
3Pain severity reduction in primary dysmenorrheaMeta-AnalysisCited 2×n=739 · large study2024
Zinc supplementation is an effective and well-tolerated option for reducing pain severity in women with primary dysmenorrhea.
Hsu TJ et al. · Nutrients (2024)
Huge benefit
← WorseNo effectBetter →
Likely real
Zinc supplementation significantly reduced pain severity compared to placebo (Hedges's g = -1.541; 95% CI: -2.268 to -0.814; p < 0.001), representing a clinically meaningful reduction in pain.
Meta-regression indicated that longer treatment durations (≥8 weeks) were associated with greater pain reduction (p = 0.003).
While higher zinc doses provided additional pain relief, the incremental benefit per additional milligram was modest (regression coefficient = -0.02 per mg; p = 0.005).
5Preterm birth risk reductionMeta-AnalysisCited 50×n=9,851 · very large study2021
There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes.
Carducci B et al. · The Cochrane database of systematic reviews (2021)
No clear effect
← WorseNo effectBetter →
The evidence suggests that zinc supplementation may result in little or no difference in reducing preterm births (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.74 to 1.03; 21 studies, 9851 participants; low-certainty evidence).
Further, zinc supplementation may make little or no difference in reducing the risk of stillbirth (RR 1.22, 95% CI 0.80 to 1.88; 7 studies, 3295 participants; low-certainty evidence), or perinatal deaths (RR 1.10, 95% CI 0.81 to 1.51; 2 studies, 2489 participants; low-certainty evidence).
There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes.
6Prevention of respiratory tract infectionsMeta-AnalysisCited 38×n=5,446 · very large study2021
In adult populations unlikely to be zinc deficient, there was some evidence suggesting zinc might prevent RTIs symptoms and shorten duration.
Hunter J et al. · BMJ open (2021)
Noticeable benefit
← WorseNo effectBetter →
Compared with placebo, oral or intranasal zinc prevented 5 RTIs per 100 person-months (95% CI 1 to 8, numbers needed to treat (NNT)=20, moderate-certainty/quality).
Sublingual zinc did not prevent clinical colds following human rhinovirus inoculations (relative risk, RR 0.96, 95% CI 0.77 to 1.21, moderate-certainty/quality).
On average, symptoms resolved 2 days earlier with sublingual or intranasal zinc compared with placebo (95% CI 0.61 to 3.50, very low-certainty/quality) and 19 more adults per 100 were likely to remain symptomatic on day 7 without zinc (95% CI 2 to 38, NNT=5, low-certainty/quality).
7Meta-AnalysisCited 158×n=451,723 · very large study2020
In addition, they further contribute to the ongoing discourse of choosing antenatal MMN over IFA as the standard of care in LMICs.
Oh C et al. · Nutrients (2020)
IFA supplementation showed notable improvement in maternal anemia and the reduction in low birthweight, whereas LNS supplementation had no apparent effect on outcomes; further research that compares LNS and MMN supplementation could help understand differences with these commodities.
For single micronutrient supplementation, improvements were noted in only a few outcomes, mainly pre-eclampsia/eclampsia (calcium), maternal anemia (iron), preterm births (vitamin D), and maternal serum zinc concentration (zinc).
These findings highlight that micronutrient-specific supplementation should be tailored to specific groups or needs for maximum benefit.
8Prevalence of zinc deficiency in IBDMeta-AnalysisCited 35×n=806 · large study2022
Clinicians in the field are advised to list zinc among trace elements to be monitored in serum.
Zupo R et al. · Nutrients (2022)
No clear effect
← WorseNo effectBetter →
Pooled analyses by the IBD subgroup showed a total population of 1677 with CD, for an overall mean zinc deficiency prevalence of 54% and 95% confidence intervals (CI) ranging from 0.51 to 0.56, versus 41% (95%CI 0.38-0.45) in the UC population (n = 806).
The overall prevalence at meta-analysis was estimated at 50% (95%CI 0.48-0.52), but with high heterogeneity, I2 = 96%.
The risk of bias across selected studies was moderate to low.
Our analysis revealed that several key glycemic indicators are significantly reduced by zinc supplementation, particularly the FG in subjects with diabetes and in subjects who received an inorganic zinc supplement.
Wang X et al. · The American journal of clinical nutrition (2019)
Our analysis revealed that several key glycemic indicators are significantly reduced by zinc supplementation, particularly the FG in subjects with diabetes and in subjects who received an inorganic zinc supplement.
Together, these findings support the notion that zinc supplementation may have clinical potential as an adjunct therapy for preventing or managing diabetes.
This trial was registered at PROSPERO as CRD42018111838.
10Cardiometabolic risk factorsMeta-AnalysisCited 23×n=1,141 · large study2020
Thus, it appeared that zinc supplementation might be associated with a decrease in cardiometabolic risk factors contributing to a reduction in risk of atherosclerosis.
Khazdouz M et al. · Biological trace element research (2020)
Large benefit
← WorseNo effectBetter →
Random- or fixed-effects meta-analysis method was used to estimate the standardized mean difference (SMD) and 95% confidence interval (CI).
Meta-analysis showed that zinc supplementation significantly decreased plasma levels of triglyceride (SMD - 0.66, 95% CI - 1.27, - 0.06), very-low-density lipoprotein (SMD - 1.59, 95% CI - 2.86, - 0.31), and total cholesterol (SMD - 0.65, 95% CI - 1.15, - 0.15).
Similarly, zinc supplementation significantly decreased fasting blood glucose (SMD - 0.52, 95% CI - 0.96, - 0.07) and HbA1c (SMD - 0.64, 95% CI - 1.27, - 0.02).
12Serum micronutrient levels in vitiligoMeta-AnalysisCited 3×n=41 · small study2024
This meta-analysis examined the effects of Copper.
Anam K et al. · Scientific reports (2024)
Publication bias was not found for the studies analysed.
This study analyses the association of serum micronutrient levels and vitiligo among patients and controls from published research along with sub-group analysis specific to Asian populations using a meta-analysis.
Low serum levels of Zinc and copper and high selenium levels are associated with Vitiligo.
13Taste acuity improvementMeta-AnalysisCited 46×n=581 · large study2017
We found very low-quality evidence that was insufficient to conclude on the role of zinc supplements to improve taste acuity reported by patients and very low-quality evidence that zinc supplements improve taste acuity in patients with zinc deficiency/idiopathic taste disorders.
Kumbargere Nagraj S et al. · The Cochrane database of systematic reviews (2017)
No clear effect
← WorseNo effectBetter →
We assessed three trials (30%) as having a low risk of bias, four trials (40%) at high risk of bias and three trials (30%) as having an unclear risk of bias.
Out of these nine, two trials assessed the patient-reported outcome for improvement in taste acuity using zinc supplements (risk ratio (RR) 1.40, 95% confidence interval (CI) 0.94 to 2.09; 119 participants, very low-quality evidence).
We meta-analysed for taste acuity improvement using objective outcome (continuous data) in idiopathic and zinc-deficient taste disorder patients (standardised mean difference (SMD) 0.44, 95% CI 0.23 to 0.65; 366 participants, three trials, very low-quality evidence).
15Risk of acute respiratory infectionsMeta-AnalysisCited 63×2021
This meta-analysis examined the effects of Vitamin C.
Abioye AI et al. · BMJ global health (2021)
No clear effect
← WorseNo effectBetter →
Likely real
Vitamin D supplementation reduced the risk of ARI (risk ratio (RR)=0.97; 95% CI 0.94 to 1.00; p=0.028) and shortened the duration of symptoms (per cent difference: -6% (95% CI -9% to -2%; p=0.003)).
Vitamin C supplementation reduced the risk of ARIs (RR=0.96; 95% CI 0.93 to 0.99; p=0.01) and shortened the duration of symptoms (per cent difference: -9% (95% CI -16% to -2%; p=0.014)).
Zinc supplementation did not reduce the risk of ARIs but shortened the duration of symptoms substantially (per cent difference: -47% (95% CI -73% to -21%; p=0.0004)).
16Antioxidant defense system parametersMeta-AnalysisCited 18×n=23 · very small study2021
To find any non-linear relationship between variables and effect size, dose-response and time-response analyses were performed.
Faghfouri AH et al. · European journal of pharmacology (2021)
Huge benefit
← WorseNo effectBetter →
Likely real
To find any non-linear relationship between variables and effect size, dose-response and time-response analyses were performed.
Zn supplementation did not have beneficial effects on glutathione peroxidase (GPx) activity (SMD = -0.34 U/g; 95% CI: -0.93, 0.25; P = 0.258).
There were significant increasing effects of Zn supplementation on glutathione (GSH) (SMD = 1.28 μmol/l; 95% CI: 0.42, 2.14; P = 0.003) and total antioxidant capacity (TAC) levels (SMD = 1.39 mmol/l; 95% CI: 0.44, 2.35; P = 0.004).
17Serum zinc concentrations in breast cancerMeta-AnalysisCited 42×n=36 · small study2019
There is a significant relationship between lowered serum Zn concentrations and risk of breast cancer onset or recurrences in women, but because of high heterogeneity, we recommend other primary studies.
Jouybari L et al. · Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS) (2019)
Large benefit
← WorseNo effectBetter →
Likely real
Significant statistical differences overall were observed, based on a random effects model (SMD (95 % CI), -0.78[-1.40, -0.16], P = 0.014).
Data from 19 of these studies indicated significant statistical differences between cancerous patients and controls with regard to serum and plasma Zn concentration (SMD [(95 %CI): -1.61(-2.43, -0.79)].
There was a significant statistical difference between the breast tissue and hair as regards Zn status (SMD (95%CI): 2.32(1.42, 3.21)) and (SMD (95v%CI): -1.80(-3.41, -0.20), respectively.
The dose of 300 mg may be useful among patients with baseline serum zinc concentration of less than 70 µg/dL, and 150 mg for 70 µg/dL or more.
Furihata K et al. · Nutrients (2020)
Noticeable benefit
← WorseNo effectBetter →
Likely real
The dose-combined overall polaprezinc increased the change from baseline by a mean of 9.08 µg/dL (95% confidence interval: 5.46, 12.70; heterogeneity: I2 = 0.61%) compared to the placebo.
A significant dose-response relationship was confirmed (p < 0.001).
Baseline serum zinc concentration was considered an effect modifier in polaprezinc 300 mg.
19Zinc concentration in autoimmune diseasesMeta-AnalysisCited 119×2018
The data presented in our work, although very heterogeneous in the manner of collecting and investigating samples, have proved to be extremely consistent in witnessing a deficiency of zinc in serum and plasma of patients compared to controls.
Sanna A et al. · Nutrients (2018)
Noticeable benefit
← WorseNo effectBetter →
Particularly for Fixed Model, Zn concentration in both serum (mean effect = -1.19; confidence interval: -1.26 to -1.11) and plasma (mean effect = -3.97; confidence interval: -4.08 to -3.87) samples of autoimmune disease patients was significantly lower than in controls.
From 26,095 articles identified by literature search, only 179 of them were considered potentially relevant for our study and then examined.
Of the 179 articles, only 62 satisfied the inclusion criteria.
20Zinc levels in coronary artery disease patientsMeta-AnalysisCited 11×n=10 · very small study2022
The findings of the meta-analysis suggest that relatively low levels of Zn might have a potential role in the pathogenesis of CAD.
Banik S et al. · Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS) (2022)
Huge benefit
← WorseNo effectBetter →
Likely real
The pooled results of the meta-analysis showed that CAD patients had significantly lower levels of Zn [SMD (95 % CI): -3.76 (-5.21, -2.31), Z = 5.08, P < 0.00001; I2= 98 %, P < 0.00001] compared with control subjects.
The findings of the meta-analysis suggest that relatively low levels of Zn might have a potential role in the pathogenesis of CAD.
Furthermore, large-scale observational studies are highly recommended in order to fully understand the association between Zn status and CAD.