Comparison guide

Zinc, vitamin C or elderberry for colds?

None of these prevents colds in most people; the real question is whether any of them shortens one. Zinc acetate lozenges have the best pooled evidence, but only at high doses started early, while vitamin C helps a little only if you were already taking it every day.

The options, compared

Option	Evidence	Best for	The honest note
Zinc Acetate Lozenges	Moderate evidence	Shortening a cold, started early	Pooled trials suggest roughly a third shorter colds at 80–92 mg elemental zinc per day begun within 24 hours of symptoms, though a later trial found no benefit. Keep courses to about one week to avoid copper deficiency, and never use intranasal zinc.	View
Vitamin C	Limited evidence	Regular users under heavy physical stress	Regular daily use modestly shortens colds (~8% in adults, ~14% in children), but it does not prevent colds in the general population and starting it once symptoms appear is not what was shown to work. People under extreme physical stress saw their risk cut in half.	View
Elderberry	Limited evidence	Not worth buying yet	Small trials suggested shorter colds and flu, but the largest and most rigorous trial found no benefit over placebo. Actual elderberry content varies widely between products, and raw berries, leaves and bark are toxic.	View

Our verdict

If you want to try something, zinc acetate lozenges started within 24 hours of the first symptom are the best-supported option, with the caveat that a later trial was null. Daily vitamin C is only worth it if you face extreme physical stress, and elderberry's evidence is too mixed to justify buying it.