Zinc
Zinc citrate in Moat at the everyday nutritional amount, zinc bisglycinate in Keel. The famous cold trials used lozenges at 80 to 207 mg, which is a different thing entirely.
Written by R. Kessler · About Knurle · Editorial policy
The short answer
Zinc is a mineral involved in immune cell function, wound healing and taste. The well-known cold trials used high-dose lozenges that dissolve in the throat at 80 to 207 mg a day; a swallowed capsule at 10 to 20 mg is an everyday nutritional amount, and the lozenge results do not transfer to it.
The form, and why it matters
Zinc citrate and zinc bisglycinate are both gentle, well-absorbed organic forms. Zinc oxide is the cheapest and the least bioavailable, which is why it appears in the cheapest multis and not in this one.
Typical dose
The adult reference intake is 8 to 11 mg a day, with a tolerable upper intake of 40 mg for adults. The cold trials used 80 to 207 mg a day in lozenge form. Moat carries 11 mg and Keel 20 mg, both daily and swallowed.
What the research shows
A meta-analysis of seven placebo-controlled trials of zinc lozenges above 75 mg a day found cold duration 33% shorter overall, with zinc acetate at 40% and zinc gluconate at 28%. A second meta-analysis found duration of nasal discharge down 34%, congestion 37%, hoarseness 43% and cough 46% at 80 to 92 mg a day. Both are lozenge studies, not capsule studies.
Who should be careful
Long-term intakes well above 40 mg a day can impair copper status and cause anaemia. Zinc on an empty stomach causes nausea in some people, so take it with food. Do not use intranasal zinc products, which have been linked to loss of smell.
Where it sits in our formulas
| Product | Form on the label | Amount per serving | % Daily Value |
|---|---|---|---|
| Moat | as zinc citrate | 11 mg | 100% |
| Keel | as zinc bisglycinate | 20 mg | 182% |
Sources
- Hemilä, Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage, Medical Research Archives
- NIH Office of Dietary Supplements, Zinc fact sheet
Figures checked against the sources above on 21 September 2026.
Vitamin C
Ascorbic acid at 180 mg a day. Regular supplementation does not stop you catching a cold; it modestly shortens the one you caught.
Read itVitamin D3
Cholecalciferol, the strongest evidence in the bottle. Daily or weekly dosing lowers respiratory infection risk, most in people who start out low.
Read itMagnesium
200 mg as oxide plus citrate. Magnesium draws water into the bowel, which is why the oxide form is the one that helps constipation.
Read itWhy zinc lozenge studies miss your capsule
The well-known zinc research used 80 to 207 mg a day in lozenges that dissolve in your throat. A daily capsule is around 11 mg and you swallow it. Here is the dose, the route, and the job each one does.
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Appetite drops, portions shrink, and the multivitamin you took with breakfast may no longer cut it. Which vitamins people run low on during GLP-1 use, why absorption shifts, and what a single daily habit can sensibly cover.
Read itEvery milligram, printed.
Each amount on the label is the amount in a full daily serving, and it matches what is on this page.
