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Zinc vs vitamin C: which supplement actually helps in winter? A UK doctor explains the evidence, NHS guidance, who should take zinc or vitamin C, and safe product options.
Summary
Zinc and vitamin C are two of the most commonly used supplements during winter, often marketed as immune “boosters”. However, the evidence behind them is very different.
This guide explains whether zinc or vitamin C actually helps in winter, who may benefit, who should avoid them, how to take them safely, and when supplementation is unnecessary — based on NHS guidance and clinical evidence.
Why zinc and vitamin C are so popular in winter
During winter, rates of colds, flu, and other respiratory infections increase. Fatigue, poor sleep, and reduced dietary variety can also affect immune resilience.
Zinc and vitamin C are often promoted as solutions, but neither prevents infection outright. Their roles are more nuanced and depend on timing, dose, and individual risk factors.
What the NHS says about zinc and vitamin C
The NHS does not recommend routine zinc or vitamin C supplementation for the general population with a balanced diet. Most people obtain sufficient vitamin C from food, and zinc deficiency is uncommon in the UK [1,4].
However, short-term zinc use during illness and targeted supplementation in specific groups may be reasonable.
Vitamin C – what it actually does
Vitamin C (ascorbic acid) is a water-soluble vitamin involved in:
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immune cell function
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collagen production
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wound healing
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antioxidant activity
Most people in the UK obtain enough vitamin C through fruit and vegetables such as oranges, berries, peppers and broccoli.
Does vitamin C prevent colds?
No. Large studies show vitamin C does not prevent colds in the general population [4].
Can vitamin C reduce symptoms?
Yes, slightly. Vitamin C may reduce the duration and severity of cold symptoms if taken regularly or started early during illness [4].
Who may benefit from vitamin C supplements?
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People with very low dietary intake
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Smokers
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Older adults with limited diets
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People under significant physical stress
For most healthy adults, routine supplementation offers little benefit.
Suggested vitamin C products (Amazon UK – no affiliate tags)
These are simple, safe options, not high-dose megaproducts.
Vitamin C tablets (1000 mg) – simple formulation
https://www.amazon.co.uk/dp/B0013OUQ3E
Vitamin C with bioflavonoids (gentler on stomach)
https://www.amazon.co.uk/dp/B0038JH1QE
Chewable vitamin C (lower dose option)
https://www.amazon.co.uk/dp/B0013OUQ6A
Zinc – what it actually does
Zinc is a trace mineral essential for:
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immune cell development
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wound healing
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taste and smell
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enzyme activity
True zinc deficiency is uncommon in the UK but can occur in:
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older adults
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people with gastrointestinal conditions
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people with very restricted diets
Does zinc help with colds?
Evidence suggests zinc may shorten the duration of cold symptoms if:
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taken within 24 hours of symptom onset
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used short-term
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taken in appropriate doses
Zinc does not prevent colds, but may modestly reduce how long symptoms last [4].
Who may benefit from zinc supplements?
Zinc may be useful for:
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adults with frequent colds
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people with poor appetite or limited diets
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older adults
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people with known zinc deficiency
Zinc should not be taken long-term without medical advice.
Suggested zinc products (Amazon UK – no affiliate tags)
These options prioritise bioavailability and safety, not megadosing.
Zinc picolinate 22 mg (high absorption)
https://www.amazon.co.uk/dp/B00020I0S8
Zinc citrate 15 mg (gentler daily dose)
https://www.amazon.co.uk/dp/B01M3ZET29
Zinc lozenges (for short-term cold use)
https://www.amazon.co.uk/dp/B0013OUQ3Y
Zinc vs vitamin C – side-by-side comparison
Zinc
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May shorten cold duration if taken early
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Best used short-term
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Risk of side effects with long-term use
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More evidence for symptom reduction
Vitamin C
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Does not prevent colds
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May slightly reduce symptom duration
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Generally safe
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Most people get enough from diet
Which should you take this winter?
For most healthy adults:
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Neither is essential daily
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Focus on diet, sleep, vaccination, and vitamin D
If choosing one:
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Zinc may be more useful during early cold symptoms
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Vitamin C may help if dietary intake is low
Neither replaces:
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Vitamin D supplementation in winter
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Flu vaccination
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Good sleep and nutrition
How to take zinc and vitamin C safely
Safety tips:
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Do not exceed recommended doses
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Avoid taking zinc for longer than 7–10 days without advice
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Zinc can cause nausea if taken on an empty stomach
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Long-term zinc use can interfere with copper absorption
Upper limits:
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Zinc: 25 mg per day (short-term only)
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Vitamin C: up to 1000 mg per day for most adults
Who should avoid zinc or vitamin C supplements?
Speak to a GP before supplementing if you:
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have kidney disease
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take certain antibiotics
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are pregnant
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have known mineral imbalances
Red flags – when to see a GP
See a GP if you experience:
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frequent or severe infections
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unexplained weight loss
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prolonged fatigue
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numbness or tingling
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symptoms not improving
Call 999 for:
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chest pain
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severe breathlessness
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collapse
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signs of sepsis
Frequently asked questions
Is zinc better than vitamin C for immunity?
Zinc has slightly more evidence for reducing cold duration, but neither prevents infection.
Can I take zinc and vitamin C together?
Yes, short-term use together is generally safe.
Should I take these all winter?
No. Routine long-term use is not recommended.
Are immune booster supplements worth it?
Most lack strong evidence and are unnecessary.
References
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NHS. Vitamins and minerals – vitamin C.
https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/ -
NHS. Vitamins and minerals – zinc.
https://www.nhs.uk/conditions/vitamins-and-minerals/zinc/ -
National Institute for Health and Care Excellence (NICE). Respiratory infections guidance.
https://www.nice.org.uk -
BMJ. Clinical evidence: Zinc and vitamin C in respiratory infections.
https://www.bmj.com/content/356/bmj.i653 -
British Nutrition Foundation. Zinc and immune health.
https://www.nutrition.org.uk/healthy-sustainable-diets/vitamins-minerals/zinc/
Affiliate Disclosure
Healthiyer may earn a commission if you buy products mentioned in this article (at no extra cost to you). Recommendations are based on NHS and NICE guidance and independent medical evidence. Commercial relationships never influence medical advice.
