Should I Take Zinc If I Feel Like I'm Getting Sick?

January 7, 2026 •

4 min read

According to a 2024 Cochrane review, taking zinc supplements may reduce the duration of an ongoing cold, but the evidence is not conclusive and needs to be balanced against potential side effects. This uncertainty has led many to question the actual benefits of zinc when early illness symptoms appear.

Quick Summary

Studies suggest that taking zinc lozenges or syrup at the first signs of a cold may shorten its duration, though its effect on symptom severity is less clear. Dosage, formulation, and potential side effects like nausea and unpleasant taste are important factors to consider. High or prolonged intake can lead to adverse health effects.

Key Points

Start early for best results: For zinc to potentially shorten a cold, it must be taken within 24 hours of the first symptoms appearing.
Choose the right form: Oral lozenges or syrups containing zinc acetate or gluconate are the most studied forms for colds; avoid nasal sprays due to the risk of permanent loss of smell.
Monitor your dosage: High daily doses (75-100 mg) are used for short-term cold treatment, but long-term or excessive intake can cause nausea and copper deficiency.
Prioritize dietary zinc: Eating a balanced diet with zinc-rich foods like meat, shellfish, and legumes is the safest way to ensure sufficient zinc for general immune function.
Consult a professional: Before taking high-dose supplements, particularly if on other medication, consult a healthcare provider to avoid interactions and side effects.
Expect modest effects: Zinc may reduce cold duration by an average of about two days, but it is not a guaranteed cure and its effect on symptom severity is less certain.

The Science Behind Zinc and the Common Cold

Zinc is an essential mineral that plays a crucial role in immune system function. It aids in the development and activation of T-cells and natural killer cells, which are vital for fighting infections. For the common cold, the theory is that zinc ions can interfere with the replication of rhinoviruses, one of the most common causes of colds. Zinc lozenges or syrups, when dissolved in the mouth, deliver these zinc ions to the mucous membranes of the throat and nose, potentially preventing the virus from multiplying.

Research on the effectiveness of zinc for the common cold has been ongoing for decades, with mixed results often attributed to variations in study design, dosage, and formulation. A key finding from multiple reviews is that zinc seems most effective when taken within the first 24 hours of symptoms appearing.

Types of Zinc Supplements and Their Effectiveness

There are several forms of zinc available in supplements, each with varying degrees of absorption and intended use:

Zinc Gluconate: A very common form, often found in over-the-counter lozenges and sprays. Several studies on lozenges containing zinc gluconate have shown a reduction in cold duration.
Zinc Acetate: Also frequently used in cold lozenges. Some meta-analyses suggest high-dose zinc acetate lozenges may offer significant benefits in shortening cold duration.
Zinc Citrate: Similar in absorption to zinc gluconate but with a less bitter taste, making it a more palatable option for some.
Nasal Zinc Sprays: These should be avoided. The FDA issued warnings against their use after some users experienced a permanent loss of their sense of smell, a condition known as anosmia.

Dosage and Risks: Balancing Benefits and Side Effects

High doses of zinc are used to treat colds, often ranging from 75 mg to 100 mg per day for a short period. This is significantly higher than the Recommended Dietary Allowance (RDA), which is 8-11 mg for most adults. It is crucial to stay within the recommended temporary dosage and not exceed 100 mg per day, as higher doses do not show better results and increase the risk of side effects.

Common Side Effects:

Nausea and Stomach Upset: One of the most frequently reported side effects, especially at high doses.
Unpleasant Taste: Many report a metallic or bad taste in their mouth when using zinc lozenges.
Headaches and Dizziness: Can occur with high doses.

Risks of Excessive Long-Term Use:

Copper Deficiency: Chronic high zinc intake (above 50 mg/day for several weeks) can interfere with copper absorption, potentially leading to anemia and neurological problems.
Weakened Immunity: Ironically, excessive and prolonged zinc supplementation can suppress immune function instead of helping it.
Drug Interactions: Zinc can interfere with the absorption of certain antibiotics, like quinolones and tetracyclines. It can also interact with certain diuretic medications.

Zinc Supplements vs. Dietary Sources


Feature	Zinc Supplements (Lozenges/Syrup)	Dietary Zinc Sources
Primary Use	Shorten cold duration if taken early.	Long-term immune support and general health maintenance.
Dosage Control	Offers higher, concentrated doses for short-term illness.	Provides lower, consistent amounts of zinc.
Absorption	Can be less efficiently absorbed than dietary zinc; effectiveness depends on formulation.	Generally more bioavailable (easily absorbed).
Side Effects	Increased risk of nausea, taste disturbances, and other side effects.	Extremely rare to cause toxicity; no risk of taste-related side effects.
Other Nutrients	Single nutrient; no additional vitamins or minerals.	Contains a wide array of other essential vitamins and minerals.
Interaction with Food	Certain foods (like dairy or high-fiber meals) can inhibit zinc absorption from supplements.	Absorption is not significantly affected by other dietary components within a balanced meal.

Conclusion

While research provides moderate evidence that zinc lozenges or syrup can help reduce the duration of the common cold, it is not a miracle cure. The potential for shortening a cold must be weighed against the risk of side effects, especially with high doses. For most people, a balanced diet rich in zinc from foods like meat, shellfish, and legumes is sufficient for daily immune support. If you choose to use zinc supplements at the onset of a cold, stick to lozenges or syrups, avoid nasal sprays, and consult a healthcare provider, especially if you take other medications or have underlying health conditions. Take zinc at the very first sign of illness and for no more than two weeks to minimize risks. For those interested in understanding more about zinc's functions, the National Institutes of Health provides an authoritative fact sheet.

Optional Outbound Link

For a comprehensive overview of zinc's role in health, consult the National Institutes of Health's Office of Dietary Supplements fact sheet.

Frequently Asked Questions

Studies on cold treatment have used daily doses of 75 mg to 100 mg of elemental zinc, typically in the form of lozenges, for a short period. However, the Tolerable Upper Intake Level is 40 mg for most adults, so consult a doctor before exceeding this amount.

No, zinc nasal sprays should be avoided. The U.S. Food and Drug Administration (FDA) warned against their use due to links with permanent loss of the sense of smell (anosmia).

Long-term, high-dose zinc supplementation is not recommended. It can lead to adverse effects like copper deficiency and suppression of the immune system. It's best to get zinc from food for daily needs.

The most common side effects reported with high-dose zinc lozenges are nausea, stomach upset, and an unpleasant or metallic taste in the mouth.

Research suggests that zinc is not effective for preventing a cold in the first place for most people. Its primary potential benefit is in shortening the duration of an existing cold.

For some individuals, studies have shown that zinc supplements, particularly lozenges taken at the onset of symptoms, can shorten a cold by approximately two days.

The mechanism of zinc lozenges involves delivering zinc ions locally to the throat and nose, where cold viruses take hold. This local contact is thought to be a key reason for their effectiveness, which may differentiate them from tablets that are swallowed.