Does zinc help wound healing?

For most people with a slow wound, a zinc supplement has not been shown to help. A 2014 Cochrane review of 6 small trials in 183 people with leg ulcers found no clear benefit from oral zinc sulfate. Pooling the 4 placebo-controlled trials in venous ulcers gave a risk ratio for healing of 1.22, with an interval from 0.88 to 1.68 that includes no effect. The review's summary gives no share of ulcers healed in each group. Zinc itself is needed for healing. The NIH Office of Dietary Supplements says zinc deficiency in older adults can delay it. What the trials have not shown is that extra zinc helps people who are not short of it.

Unsettled. The newest pooled analysis leans the other way. A 2025 meta-analysis of 5 trials put the effect on ulcers healed at 1.41, with an interval from 1.04 to 1.92, rated moderate quality. It pooled zinc oxide applied to the wound with zinc sulfate taken by mouth, from trials run between the 1960s and the 1990s, so it does not tell you whether a tablet works. Its abstract also labels the figure a mean difference, while the text describes a ratio of healed ulcers.

What the trials found

Leg ulcers

The Cochrane authors concluded that oral zinc sulfate does not appear to help arterial or venous leg ulcers heal. They added that all the included trials were small and at unclear risk of bias because of poor reporting. Four of the trials compared zinc with placebo in venous ulcers, and pooling them gave the 1.22 above, which did not reach statistical significance. The review has not been updated since 2014.

One trial inside the 2025 review hints at who might gain. People with leg ulcers took 200 mg of zinc sulfate three times a day for 4 months. Those whose blood zinc started below 16.8 umol/L healed 5 of 7 ulcers on zinc against 1 of 7 on placebo, and those above that line saw no benefit. That is 14 people, and the interval runs from 0.77 to 32.5, which includes no effect. The idea that zinc helps only when you are short of it is a hypothesis from this subgroup.

Pressure ulcers

A 2024 Cochrane review of nutrition for pressure ulcers called the evidence very uncertain for zinc supplements and for mixes of protein, arginine, zinc and antioxidants. In the 2 studies of those mixes, 71 people, ulcer area was 2 cm2 smaller against a standard diet, with an interval from 4.54 smaller to 0.53 larger. A 2020 meta-analysis of 7 randomized and non-randomized studies did find zinc linked with better healing, a relative risk of 1.44 with an interval from 1.01 to 2.06. The lower end of that interval sits next to no effect, and the mix of designs is why we rate it below the Cochrane review.

The largest single trial gave 200 malnourished people with stage II to IV pressure ulcers 14 fl oz (400 mL) a day of a high-protein formula enriched with arginine, zinc and antioxidants for 8 weeks. Ulcer area shrank by 60.9 percent against 45.2 percent on a matched formula, an adjusted difference of 18.7 percent with an interval from 5.7 to 31.8. The number of ulcers that closed completely was no different. Zinc was one ingredient among several, so the result cannot be credited to zinc, and it applies to people who were malnourished.

Diabetic foot ulcers

A 2020 Cochrane review of 9 trials in 629 people with diabetic foot ulcers found one zinc trial and rated its effect on ulcer size as uncertain, on very low certainty evidence. In that trial, 60 people aged 40 to 85 with grade 3 ulcers took 220 mg of zinc sulfate, which is 50 mg of elemental zinc, or placebo for 12 weeks. Ulcer length shrank by 0.59 in (1.5 cm) on zinc against 0.35 in (0.9 cm) on placebo, and width by 0.55 in (1.4 cm) against 0.31 in (0.8 cm). It was a single center in Iran, and the dose is above the adult upper limit for zinc.

Burns

A 2016 meta-analysis of 8 studies in 398 people aged 6 to 67 with severe burns, half of them randomized, looked at selenium, copper and zinc. Trace elements given together by drip cut infectious episodes, a weighted mean difference of 1.25 fewer with an interval from 0.80 to 1.70 fewer. For oral zinc the authors reported only a possible benefit on deaths. The review did not pool how fast burns healed with zinc, and this is hospital treatment for severe burns, far from a supplement taken at home.

Who should be careful

Not for everyone. The adult upper limit for zinc is 40 mg a day, and for children and teenagers it is 4 to 34 mg depending on age. According to NIH ODS, 50 mg or more a day for weeks can block copper absorption, weaken immune function and lower HDL cholesterol, and copper markers have fallen at about 60 mg a day for up to 10 weeks. The 50 mg of elemental zinc used in the diabetic foot trial is above that adult limit, and so is the 200 mg of zinc sulfate three times a day used in the leg ulcer trial.

Zinc also blocks the absorption of quinolone and tetracycline antibiotics, and they block zinc. NIH ODS advises taking the antibiotic at least 2 hours before or 4 to 6 hours after the zinc. That matters if a wound is infected and you are on one of these antibiotics. We found no evidence specific to pregnancy for this question.

What expert bodies say

NIH ODS says zinc deficiency in older adults can delay wound healing. It does not say that supplements help people who are not deficient. An international guideline on pressure injuries, from EPUAP, NPIAP and PPPIA, was updated in 2025, and we could not retrieve the wording of its zinc recommendation, so it is not used on this page.

How we searched

What would change this answer

• A large randomized trial of oral zinc that splits people by their starting blood zinc. That would test whether the benefit lives only in people who are short of it. We found no such trial registered.
• A trial that counts how many wounds close, not only how much they shrink, at a dose within the upper limit of 40 mg a day.
• Pooled results that keep zinc taken by mouth apart from zinc put on the wound.

What zinc does, how much you need and who runs short is on the zinc guide.

Sources

1. ev-znwh-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 6 trials, 183 participants
   Serum zinc was measured in four trials and four trials compared oral zinc sulphate with placebo in people with venous ulcers; pooling these trials indicated no statistically significant difference between the two groups for healing (RR 1.22, 95%CI 0.88 to 1.68).
   
   Who: people with arterial or venous leg ulcers; pooled analysis of 4 placebo-controlled trials in venous ulcers
   Effect: ulcer healing RR 1.22 (95% CI 0.88 to 1.68), not significant
   Certainty: Seventh update; all RCTs are small, risk of bias unclear. The main argument for "no" for chronic leg ulcers.
   Cochrane Database Syst Rev, 2014 · checked 2026-10-07 · we read the abstract
2. ev-znwh-02 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 6 trials, 183 participants
   AUTHORS' CONCLUSIONS: Oral zinc sulphate does not appear to aid the healing of arterial and venous leg ulcers, however all included studies were small and at unclear risk of bias (due to poor reporting).
   
   Who: people with arterial or venous leg ulcers
   Effect: no evidence of benefit; all trials small, unclear risk of bias
   Certainty: Conclusion of the Cochrane authors; no updates after 2014.
   Cochrane Database Syst Rev, 2014 · checked 2026-10-07 · we read the abstract
3. ev-znwh-03 · Meta-analysis or systematic review · systematic review and meta-analysis of clinical trials · n = 9 studies reviewed, 5 trials pooled
   Based on this systematic review, zinc treatment could promote wound healing compared with control (p=0.03).
   
   Who: patients with chronic wounds, mostly leg ulcers, given oral zinc sulfate or topical zinc oxide
   Effect: ulcers healed at final endpoint 1.41 (95% CI 1.04 to 1.92), p = 0.03; GRADE moderate
   Certainty: The number is from the abstract (the authors write "MD", but by meaning it is a risk ratio); topical ZnO was included in the pool, so the result is not about the tablet. Studies from the 1960s to 1990s.
   BMJ Nutrition, Prevention & Health, 2025 (systematic review and meta-analysis of the effect of zinc on wound healing) · checked 2026-10-07 · we read the fulltext
4. ev-znwh-04 · Randomized controlled trial(s) · double-blind RCT, subgroup analysis reported within a systematic review · n = 27 patients
   However, on examining the baseline, Zn serum levels in both study groups, patients with serum levels lower than 16.8 µmol/L had their wounds healed five times faster than the respective patients in the placebo group (5/7 vs 1/7) (95% CI 0.77 to 32.5).
   
   Who: patients with leg ulcers, 200 mg zinc sulfate three times a day for 4 months, split by baseline serum zinc below or above 16.8 umol/L
   Effect: serum zinc < 16.8 umol/L: 5/7 vs 1/7 healed (95% CI 0.77 to 32.5); >= 16.8 umol/L: no benefit
   Certainty: Subgroup of 14 people, wide CI; the idea "helps only in deficiency" is a hypothesis, not proof.
   BMJ Nutrition, Prevention & Health, 2025 (systematic review and meta-analysis of the effect of zinc on wound healing) · checked 2026-10-07 · we read the fulltext
5. ev-znwh-05 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 33 RCTs, 7920 participants overall; protein, arginine, zinc and antioxidant comparison 2 studies, 71 participants
   Compared to standard diet, the evidence is very uncertain about the effect of protein, arginine, zinc and antioxidant supplements on pressure ulcer healing (pressure ulcer area: mean difference (MD) 2 cm² smaller, 95% CI 4.54 smaller to 0.53 larger; 2 studies, 71 participants, very low-certainty evidence).
   
   Who: people with pressure ulcers in RCTs of nutritional supplements vs standard diet
   Effect: pressure ulcer area MD 2 cm2 smaller (95% CI 4.54 smaller to 0.53 larger), very low certainty
   Certainty: The latest Cochrane (search to May 2022). Zinc separately: 1-2 studies, very low.
   Cochrane Database Syst Rev, 2024 · checked 2026-10-07 · we read the abstract
6. ev-znwh-06 · Meta-analysis or systematic review · Cochrane systematic review of RCTs · n = 9 RCTs, 629 participants (one zinc trial)
   It is uncertain whether the following interventions change parameters of ulcer dimensions over time when compared with placebo; 220 mg zinc sulphate supplement containing 50 mg elemental zinc, 250 mg magnesium oxide supplement, 1000 mg/day omega-3 fatty acid from flaxseed oil supplement, magnesium and vitamin E co-supplementation and vitamin D supplementation.
   
   Who: people with diabetes and foot ulcers in RCTs of oral nutritional interventions
   Effect: zinc sulfate 220 mg (50 mg elemental zinc): uncertain effect on ulcer dimensions; very low certainty
   Certainty: Zinc here is one RCT (ev-znwh-07); Cochrane downgraded for bias, indirectness, imprecision.
   Cochrane Database Syst Rev, 2020 · checked 2026-10-07 · we read the abstract
7. ev-znwh-07 · Randomized controlled trial(s) · randomized, double-blind, placebo-controlled trial · n = 60 patients
   After the 12-week intervention, compared with the placebo, zinc supplementation was associated with significant reductions in ulcer length (-1.5 ± 0.7 vs. -0.9 ± 1.2 cm, p = 0.02) and width (-1.4 ± 0.8 vs. -0.8 ± 1.0 cm, p = 0.02).
   
   Who: patients aged 40 to 85 years with grade 3 diabetic foot ulcer, 220 mg zinc sulfate (50 mg elemental zinc) daily vs placebo for 12 weeks
   Effect: ulcer length -0.59 vs -0.35 in (-1.5 vs -0.9 cm) (p = 0.02); width -0.55 vs -0.31 in (-1.4 vs -0.8 cm) (p = 0.02); complete healing not reported
   Certainty: A single RCT from one center (Iran); the 50 mg dose is above the UL of 40 mg (see ev-znwh-12).
   Wound Repair Regen, 2017 · checked 2026-10-07 · we read the abstract
8. ev-znwh-08 · Randomized controlled trial(s) · multicentre, randomized, controlled, blinded trial · n = 200 patients
   Supplementation with the enriched formula (n = 101) resulted in a greater reduction in PU area (mean reduction, 60.9% [95% CI, 54.3% to 67.5%]) than with the control formula (n = 99) (45.2% [CI, 38.4% to 52.0%]) (adjusted mean difference, 18.7% [CI, 5.7% to 31.8%]; P = 0.017).
   
   Who: adult malnourished patients with stage II to IV pressure ulcers in long-term or home care, 400 mL/day of formula
   Effect: PU area reduction 60.9% vs 45.2%, adjusted mean difference 18.7% (95% CI 5.7% to 31.8%); complete healing no different
   Certainty: Zinc is only one of the ingredients; the effect cannot be attributed to zinc alone. Undernourished only.
   Ann Intern Med, 2015 · checked 2026-10-07 · we read the abstract
9. ev-znwh-09 · Observational data · systematic review and meta-analysis including RCTs and non-RCTs · n = 7 studies
   The intervention group significantly had improved healing vs that of the control group (relative risk, 1.44; 95% CI, 1.01-2.06; P = 0.043, I2 = 19.3%).
   
   Who: patients with pressure injuries given zinc vs control nutrition
   Effect: healing RR 1.44 (95% CI 1.01 to 2.06), I2 19.3%
   Certainty: Mixed designs (not only RCTs), hence C. Lower CI bound near 1; Cochrane 2024 rates these same data as very uncertain.
   Nutr Clin Pract, 2020 · checked 2026-10-07 · we read the abstract
10. ev-znwh-10 · Observational data · systematic review and meta-analysis of randomized and non-randomized trials · n = 8 studies (4 RCTs, 4 non-randomized), 398 participants
    Oral zinc supplementation shows possible beneficial effects on mortality.
    
    Who: patients with severe burn injury, age 6 to 67 years, given selenium, copper and zinc alone or combined
    Effect: combined parenteral trace elements: infectious episodes WMD -1.25 (95% CI -1.70 to -0.80); oral zinc: possible mortality benefit
    Certainty: Mixed designs; healing rate separate from zinc is not pooled. Burns involve hospital parenteral therapy, not a dietary supplement at home.
    J Burn Care Res, 2016 · checked 2026-10-07 · we read the abstract
11. ev-znwh-11 · Position of an expert body · government fact sheet · n = —
    Zinc deficiency in older adults can cause delays in wound healing and changes in cognitive and psychological function
    
    Who: older adults with zinc deficiency
    Effect: deficiency linked to delayed wound healing
    Certainty: Authority position on deficiency; ODS does not speak about the benefit of supplements for people without deficiency.
    NIH Office of Dietary Supplements, Zinc fact sheet for health professionals · checked 2026-10-07 · we read the section
12. ev-znwh-12 · Position of an expert body · government fact sheet · n = —
    Doses of 50 mg of zinc or more over a period of weeks can inhibit copper absorption, reduce immune function, and lower high-density lipoprotein cholesterol levels; however, it is unlikely that a person would obtain this much zinc from food alone. The Tolerable Upper Intake Level for zinc is 40 mg for adults, and it ranges from 4 to 34 mg for infants, children, and adolescents, depending on age.
    
    Who: adults; children and adolescents have upper limits of 4 to 34 mg
    Effect: UL 40 mg/day adults; 50 mg/day or more for weeks impairs copper absorption, immune function and HDL
    Certainty: Doses in the wound RCTs (50 mg elemental zinc; 200 mg sulfate three times a day) are higher than the UL of 40 mg.
    NIH Office of Dietary Supplements, Zinc fact sheet for health professionals · checked 2026-10-07 · we read the section
13. ev-znwh-13 · Position of an expert body · government fact sheet · n = —
    Reductions in erythrocyte copper-zinc superoxide dismutase, a marker of copper status, have been reported with even moderately high zinc intakes of approximately 60 mg/day for up to 10 weeks [3].
    
    Who: people taking high doses of zinc supplements
    Effect: about 60 mg/day for up to 10 weeks lowers erythrocyte copper-zinc superoxide dismutase
    Certainty: Copper deficiency from zinc: anemia, neutropenia (the 2025 MA also mentions it).
    NIH Office of Dietary Supplements, Copper fact sheet for health professionals · checked 2026-10-07 · we read the section
14. ev-znwh-14 · Position of an expert body · government fact sheet · n = —
    Taking the antibiotic at least 2 hours before or 4 to 6 hours after the zinc supplement minimizes this interaction [103].
    
    Who: people taking quinolone or tetracycline antibiotics and zinc supplements
    Effect: mutual absorption interference; separate doses by 2 hours before or 4 to 6 hours after
    Certainty: Relevant specifically for wounds: infected ulcers are often treated with ciprofloxacin or doxycycline.
    NIH Office of Dietary Supplements, Zinc fact sheet for health professionals · checked 2026-10-07 · we read the section