Compound or practice · Supplement
Zinc
An immune and hormone cofactor that shortens colds when dosed right — and drains copper when overdone.
- Overall grade
- Grade B
- Last revised
- 3
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
1 at grade A · 1 at grade B · 1 at grade D — 3 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Correcting deficiencyEvidence grade A
Immune, growth, wound healing
Moderatehigh
- Cold duration (lozenges at onset)Evidence grade B
Form/dose sensitive
Moderatemixed
- Testosterone (replete men)Evidence grade D
Only helps if deficient
Trivialhigh
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
Interactions
Documented pairings with supplements and medicines. A medicine on this list is a conversation for whoever prescribes it.
CopperDepletes a nutrient
High-dose zinc induces copper deficiency — balance ~15:1 or test.
IronMind the timing
Competes with iron for absorption — take at different meals.
AntibioticsMind the timing
Chelates quinolones/tetracyclines — separate 2+ hours.
Tongkat AliWorks together
Free-T support assumes zinc sufficiency.
The evidence in words
What it is
Zinc is an essential trace mineral and structural cofactor in hundreds of enzymes and transcription factors. Mild deficiency exists, especially in vegetarians and older adults, because phytates in grains and legumes reduce absorption.
How it works
Zinc stabilizes 'zinc-finger' proteins that read DNA, supports immune-cell function and wound healing, and is a cofactor in testosterone and thyroid metabolism. Zinc lozenges are thought to interfere directly with rhinovirus replication in the throat.
What the evidence shows
Correcting deficiency is grade A. Zinc lozenges started within 24 hours of cold onset modestly shorten duration in meta-analysis — form and dose matter (ionic zinc, frequent lozenges). It supports testosterone only when you were deficient; it does nothing extra in replete men. Chronic high doses induce copper deficiency, a real and under-recognized harm.
How to use it
8–15 mg/day covers requirements. For colds, ~75 mg/day of ionic zinc as lozenges, split, only during the illness. Do not take 40 mg+/day long-term without balancing copper.
Safety & interactions
Acute high doses nauseate; chronic high intake causes copper deficiency (anemia, neuropathy). Keep long-term supplemental zinc modest and pair with copper if dosing high. Copper — High-dose zinc induces copper deficiency — balance ~15:1 or test. Iron — Competes with iron for absorption — take at different meals. antibiotics — Chelates quinolones/tetracyclines — separate 2+ hours. Tongkat Ali — Free-T support assumes zinc sufficiency.
Bottom line
Fix a deficiency, shorten a cold with lozenges at onset — but respect the ceiling: sustained 40 mg+/day quietly drains copper.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Maintenance
- 8–15 mg/day.
- Cold
- ~75 mg/day ionic lozenges, split, during illness only.
Goes with
- Tongkat AliFree-T support assumes zinc sufficiency.Evidence grade C
Related reading
Entries that share this one's tags or conditions.
- Zinc for Cold duration (lozenges at onset)Evidence grade B — Form/dose sensitiveEvidence grade B
- Zinc for Correcting deficiencyEvidence grade A — Immune, growth, wound healingEvidence grade A
- Zinc for Testosterone (replete men)Evidence grade D — Only helps if deficientEvidence grade D
- Zinc: dosage and how to take it8–15 mg/day.Evidence grade B
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.