Cold Prevention
Reduced frequency and duration of common cold infections.
TL;DR
Zinc lozenges (started within 24 h of symptoms) and regular vitamin C have the best evidence for colds — zinc shortens duration, vitamin C prevents colds mainly in heavy exercisers. Probiotics modestly reduce incidence.
Why It Matters
The common cold (rhinovirus et al.) has no cure, but prevention and duration can be influenced. Meta-analyses: zinc acetate/gluconate lozenges (75+ mg/day elemental, started early) shorten colds by ~30%; regular vitamin C (1 g/day) reduces incidence in athletes/cold exposure but not the general population; probiotics reduce upper respiratory infection incidence modestly.
How to Measure
Track incidence, duration, and severity of colds over a winter season.
Biomarkers
Optimization Protocol
Prevention: vitamin C 1 g/day (strongest rationale for athletes), vitamin D to sufficiency if deficient, probiotic daily during season. At first symptom: zinc acetate lozenges 75+ mg/day elemental, dissolved slowly, for the duration of the cold.
Lifestyle Levers
- •Sleep 7–9 h (strong infection-resistance data)
- •Hand hygiene
- •Regular moderate exercise
- •Manage stress
- •Humidify dry indoor air
Supporting Supplements
Zinc
Zinc lozenges started within 24 hours of symptoms shorten colds by ~30%; prevention evidence is weaker.
Probiotics
Probiotics modestly reduce upper respiratory infection incidence and duration in meta-analyses.
Echinacea
Echinacea results are inconsistent; some preparations show small reductions in cold incidence and duration.
Elderberry
Elderberry shows reduced cold/flu duration in small trials; evidence quality is limited.
Vitamin C
Vitamin C does not prevent colds in the general population but halves incidence in heavy exercisers and shortens colds ~8%.
Vitamin D
Vitamin D supplementation reduces acute respiratory infections, with strongest benefit in deficient individuals.
Supporting Research
Frequently Asked Questions
Typical Timeframe
Prevention: across a season. Zinc: duration shortened when started within 24 hours.
Research Summary
My Notes
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.