So we’ve already investigated whether or not Vitamin C can prevent colds, but I bet part of you is reading this because you HAVE taken all the usual supplements and meds… yet the scratchy throat and runny nose is still wreaking havoc on your life.
Naturally, you’d rather get this over with sooner than later. And funnily enough, there’s another supplement that currently keeps appearing in dialogue and online about recovering from a cold faster: zinc.
One that I’ve specifically encountered are zinc lozenges, which some people in my social circle swear up and down by the second they feel a funny feeling in their throat.
Now this wouldn’t be After the Abstract if I didn’t immediately go: but can zinc actually help shorten a cold? Are we all just desperately searching for the final surefire way that whacks the cold into oblivion and saves us from this misery?
Here’s the answers I could find!
The Short Answer
Possibly yes! Zinc may shorten a cold by around two days.
Research suggests that zinc, particularly when used as a treatment after symptoms begin, may help reduce how long a cold lasts. Several systematic reviews have reported an average reduction of approximately two days compared with placebo.
Which, let’s be real, doesn’t sound half bad when you’re spending your days surrounded by tissues. And i’m pretty sure that most of us would take even the smallest amount of relief on an especially bad day where nothing seems to work at all. Cause honestly, what’s there to lose, right?
But, as usual, there’s always a catch. Sadly I do have to report, that the results differ considerably between studies, the certainty of the evidence is limited, and zinc can cause unpleasant side effects.
So in plain English: Zinc may help you recover from a cold faster, but it isn’t guaranteed. And not every zinc supplement has been shown to work the same way.
What Does The Evidence Actually Say?
Let’s begin with the largest review that I found during my research: In 2024, a Cochrane review examined 34 randomized controlled trials involving 8,526 participants to investigate whether zinc could prevent or treat colds. In order to answer the question regarding treatment, the researchers pooled eight trials involving 972 participants and found that zinc shortened colds by approximately 2.4 days compared with placebo.
Honestly, that sounds promising! And to add even more good news, it wasn’t the first review to find something similar!
In 2020, Wang and colleagues examined randomized trials involving micronutrient supplementation in healthy adults. When they pooled six studies investigating zinc lozenges, they found an average reduction in cold duration of 2.25 days.
A year later, Hunter and colleagues published another systematic review involving 28 trials and 5,446 participants. Their treatment analysis also suggested that symptoms resolved around two days earlier in participants receiving zinc.
However, I do wish to mention that Hunter et al. examined acute viral respiratory infections a lot more broadly than the others did, which focused exclusively on the common cold. Please keep this in mind when forming your own conclusion!
There’s also an interesting earlier analysis from HemilĂ€ and colleagues, published in 2016. Using individual participant data from three randomized trials involving 199 people, the researchers found that zinc acetate lozenges shortened colds by approximately 2.7 to 2.9 days, depending on the analysis.
Considering that colds lasted around seven days in the placebo groups, that would be a noticeable difference.
Okay, so far, zinc sounds pretty good, right? Well, not quite so fast.
In 2020, HemilÀ and colleagues conducted another randomized trial, this time using commercially available zinc acetate lozenges.
The researchers randomized 253 participants in advance, of which 87 eventually developed a cold and were then included in the main analysis.
And this time? No statistically significant improvement in recovery was found by the researchers.
In fact, the zinc group tended to recover more slowly, although the overall difference was not statistically significant.
Honestly, to me, it felt a bit like the dangling carrot got taken away.
So while several reviews suggest a potentially useful effect, individual studies don’t always agree.
đŹ For the curious: Ok but then.. does zinc maybe prevent colds?
The 2024 Cochrane review found little or no clear reduction in the likelihood of catching a cold when zinc was used preventively. Across nine trials involving 1,449 participants, the estimated reduction was small and statistically uncertain.
Interestingly, Hunter’s 2021 review reported some preventive benefits for symptoms of viral respiratory infections. But like I mentioned earlier, they also examined a way broader range of illnesses, zinc administration and outcomes.
So these findings aren’t necessarily asking or answering exactly the same question.
For our everyday question of whether taking zinc keeps you from catching the common cold, the evidence remains uncertain.
The final take-home-message, is that Zinc currently looks more promising for shortening an existing cold than reliably preventing one.
What Changes The Answer?
Multiple factors, actually! For starters, not all the studies investigated the same products. Some used zinc acetate lozenges, others zinc gluconate, and some investigated entirely different formulations. There were also differences in dosage, treatment duration and when participants started taking zinc. This part is of importance because positive trials investigated lozenges, and they had also started them soon after symptoms had appeared.
The second big factor is, that these reviews share some of the same underlying trials.
Wang, Hunter, HemilĂ€’s 2016 analysis and Cochrane aren’t four completely independent confirmations of the same effect.
All of which makes determining exactly how well zinc works, and which formulation works best, surprisingly difficult.
What Does This Mean In Real Life?
If you’re considering zinc for your next (or current, honestly) cold, the evidence suggests that certain oral zinc products, especially lozenges, might help shorten its duration.
And there is something else to consider: side effects.
The 2024 Cochrane review found that non-serious adverse effects were more common in people taking zinc for cold treatment. While some harmless ones included unpleasant taste or slight irritation of the mouth, some others included digestive problems and nausea. Additionally, something that would require a consultation with your primary care physician, is that: High zinc intakes can also interfere with copper absorption when taken over longer periods.
For example: The NIH lists 40 mg per day as the tolerable upper intake level for adults, including zinc from food and supplements.
Some treatment studies used considerably higher doses for short periods. However, these research doses definitely shouldn’t be treated as an everyday recommendation, especially when the ideal or most effective dose still hasn’t been established by government institutions or researchers.
Zinc can also interact with medications, including certain antibiotics.
So before experimenting with high-dose zinc treatments, speaking with a pharmacist or healthcare professional is the only correct option.
And zinc products used inside of the nose should definitely not be taken. These types of products have been linked to potentially long-lasting or even a permanent loss of smell.
đłïž đ Rabbit Hole: This just in – not all zinc lozenges are created equal!
Okay, let’s rewind for a second.. Remember that 2016 analysis that found colds were almost three days shorter? Those researchers investigated zinc acetate lozenges.
But in 2020, another trial investigated zinc acetate lozenges and found no significant benefit.
Same type of zinc, but rather different outcomes…. uhm.. but how does that happen?
Well, the 2020 researchers pointed out that their lozenges dissolved relatively quickly, in approximately eight minutes. Participants also took them for a maximum of five days.
Earlier positive trials had used different formulations and treatment schedules.
The authors wondered whether factors such as how long a lozenge remains in contact with the mouth and throat, the amount of zinc delivered and the treatment duration could explain some of these differences.
The hypothesis may be interesting, but it hasn’t been fully researched yet.
And importantly, the negative trial doesn’t prove zinc was harmful or ineffective in every possible formulation. What it does show is that two products labelled zinc acetate aren’t necessarily interchangeable in their clinical effects. Which makes the question of what actually constitutes an effective zinc lozenge considerably more complicated than it first appears.
EVIDENCE VERDICT
Hey, its promising! But we do still have some unanswered questions.
How convincing is the evidence?
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Several randomized trials and systematic reviews suggest that zinc may shorten colds by approximately two days.
But study results are inconsistent, the certainty of treatment evidence is low, and we still don’t know which formulation and dose offer the most reliable benefit.
There’s also little convincing evidence that zinc consistently reduces how severe a cold feels overall.
Does it change what we should do?
Perhaps, but cautiously. Oral zinc lozenges may be worth discussing as a short-term treatment option, particularly early in a cold. However, taking zinc regularly just to prevent a cold isn’t currently strongly supported by the most recent Cochrane evidence. And higher doses are not automatically better or safer.
The Bottom Line
Zinc might genuinely help you get over a cold faster. Some studies have reported reductions in illness duration of two days or more, which is certainly more than nothing. But not every study has found a benefit, and the differences between these leave us with some unanswered questions.
References & Sources
View the studies behind this article
- Nault D, Machingo TA, Shipper AG, Antiporta DA, Hamel C, Nourouzpour S, Konstantinidis M, Phillips E, Lipski EA, Wieland LS.
Zinc for prevention and treatment of the common cold.
Cochrane Database Syst Rev. (2024)
[Read the Study] - Wang MX, Win SS, Pang J.
Zinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation. Am J Trop Med Hyg. (2020)
[Read the Study] - Hunter J, Arentz S, Goldenberg J, Yang G, Beardsley J, Myers SP, Mertz D, Leeder S. Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials.
BMJ Open. (2021)
[Read the Study] - HemilÀ H, Petrus EJ, Fitzgerald JT, Prasad A.
Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis.
Br J Clin Pharmacol. (2016)
[Read the Study] - HemilÀ H, Haukka J, Alho M, Vahtera J, KivimÀki M.
Zinc acetate lozenges for the treatment of the common cold: a randomised controlled trial.
BMJ Open. (2020)
[Read the Study] - National Institutes of Health
Zinc – Fact Sheet for Health Professionals
[Read the Source]
Written by A Dose of Proof
Health research can be fascinating â but the way itâs written often makes it much harder to understand than it needs to be.
A Dose of Proof is the voice behind After the Abstract, translating health research into clear, evidence-focused explanations that look beyond the headline â including what a study found, what it didnât prove, and whether the results actually matter.
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