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Zinc

Zinc

Best for

Reduce diarrhea and recover faster

Proven modest benefit · 2–10 mg/day for 2–78 weeks · 2 meta-analyses , n=35.6k

48 papers · 9 claims · 104 outcomes scored · 6 positive

Evidence overview

Evidence overview Proven modest benefit

Zinc provides a proven modest benefit for acute diarrhea recovery and blood sugar control, with the clearest gains in people with diarrhea or low zinc intake.

  • Across 3 studies (n=35,592), zinc improved 23 diarrhea endpoints, the clearest benefit in acute diarrhea.2
  • Five trials (n=1,035) found modest improvements in blood sugar control and insulin sensitivity.3
  • Cold lozenges deliver only a tiny benefit, far smaller than the diarrhea signal.4

Outcomes

What zinc actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect Evidence Dose Weeks Rank
Reduce diarrhea and recover faster Proven modest benefit
small 		3 meta-analyses n=36k Meta-analyzed 2–10 mg 2–78 wk —
Improve insulin sensitivity Likely modest benefit
small 		5 meta-analyses n=1.1k Meta-analyzed 4.29–149.82 mg 8–52 wk #5/79
Steady your blood sugar levels Likely modest benefit
small 		5 meta-analyses n=1.0k Meta-analyzed 4.29–149.82 mg 8–52 wk #10/110
Catch fewer colds and infections Not enough research
small 		2 meta-analyses n=591 Meta-analyzed 5–42.9 mg 78 wk —
Recover from colds faster Likely real but unnoticeable
trivial 		4 meta-analyses n=1.5k Meta-analyzed 5–50 mg 1 wk #2/10
Ease cold and flu severity Not enough research
trivial 		3 meta-analyses n=520 Meta-analyzed 50–150 mg 1–6 wk —
Build key mineral stores Likely real but unnoticeable
trivial 		18 meta-analyses n=18k Meta-analyzed 0.9–300 mg 2–42 wk #3/5
Ease bronchitis symptoms Not enough research
1 RCT n=— 50–150 mg 6 wk —
Support pancreas insulin output Not enough research
1 RCT n=— 30 mg 52 wk —

Forms & standardisation

Look for the elemental zinc amount on the label, because the salt name alone does not tell you how much actual zinc you are getting. The best-studied forms in this evidence set are zinc sulfate for diarrhea, and zinc acetate or zinc gluconate for cold lozenges.24 If a product hides the form or only talks about the brand name, skip it and pick the one that tells you the elemental dose clearly.1

Risk profile

Adverse events and known drug interactions

Safety events

acute respiratory distress syndrome severe
cardiac arrhythmia severe
Refractory hypoxemia (ECMO cannulation) severe
prostate cancer, aggressive severe
Hospitalizations for genitourinary causes moderate
Elevated liver enzymes (ALT/AST) moderate
Nervous system symptoms (involuntary shaking/lower limb tremor) moderate
Anemia (self‑reported) mild

Drug interactions

Lovastatin major decreases effect
Penicillamine moderate decreases effect
other moderate decreases effect
Carbamazepine moderate decreases concentration
Sodium Valproate moderate decreases concentration
Phenytoin moderate decreases concentration
Clonazepam moderate decreases concentration
Levetiracetam moderate decreases concentration
Intravenous Immunoglobulin moderate additive
Ciprofloxacin moderate decreases effect

Co-studied with

Supplements that share evidence with zinc

Frequently asked

Common questions

What does zinc actually do in your body?

It acts like the metal clip that lets hundreds of enzymes and signaling proteins do their jobs cleanly. That is why low zinc hits so many systems at once, including immune function and glucose handling.1

Does zinc help with colds?

The cold data do not show a miracle, but they do show a small reduction in how long you stay sick when the form and dose match the trials.4 If you want a dramatic cold fix, zinc will disappoint you.

How long does zinc take to work?

If you are low, blood levels and related markers usually move over weeks, not days, and the better glucose trials ran for months.13 For diarrhea, the studied treatment window was much shorter, about 2 weeks.2

What form of zinc is best?

Look at the elemental zinc amount first, then check the salt name. Zinc sulfate shows up in diarrhea studies, while zinc acetate and zinc gluconate show up most in cold lozenges.24

Sources

  1. 1. NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals
  2. 2. Zinc supplementation for acute diarrhea, systematic review and meta-analysis
  3. 3. Zinc supplementation and glycemic control, meta-analysis
  4. 4. Zinc lozenges for the common cold, systematic review and meta-analysis

Generated May 15, 2026

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