In 1979, a 3-year-old girl named Karen was undergoing chemotherapy for leukemia in Austin, Texas. The treatment was saving her life — but it had destroyed her immune system. Every cold hit her hard, and her doctor warned that once a cold took hold, it could last for months [1].
Her father, George Eby, was giving her zinc tablets to bring up her levels and improve her immune system's function [2]. One afternoon, as yet another cold was flaring up, Karen refused to swallow the zinc tablet. She complained that her throat was too sore and she just wanted to sleep. So Eby told her to crush it with her teeth and let it dissolve in her mouth while she took a nap.
After several hours, she woke from her nap playing and smiling. The cold was gone. Eby, skeptical, told her to go back to bed. But she knew what she felt. She said, "No, Daddy, zinc cured my cold" [1].
It was an accident. A tired child, a tablet she wouldn't swallow, and a father who noticed what happened next. But that accident would launch decades of research into something millions of people experience every year — and most of us still handle the wrong way.
Table of Contents
- Zinc Lozenges: The Accidental Discovery
- Saline Nasal Irrigation
- Honey: The Oldest Remedy
- Practical Steps for the First 24 Hours
- The Frontier
- References
Zinc Lozenges: The Accidental Discovery
Because here's the problem: most of what we reach for when a cold strikes doesn't actually work. High-dose vitamin C, echinacea, garlic, megadoses of vitamin D — all tested in human clinical trials, none of them effective. Yet companies keep selling them to people who are desperate to feel better. That's a billion-dollar industry built on remedies that fail when you test them properly.
So what does work? Starting with that accidental discovery in Texas, Eby set out to find some answers. He dove into the literature for clues. He found that zinc's effects on viruses had been explored in the laboratory. In the petri dish, zinc ions interfere with a virus's ability to replicate and spread. These results had been seen with a number of viruses — including examples of the type that cause the common cold [2].
He wasn't sure about the mechanism. But he was sure of what he'd seen with his daughter, Karen. Could it work for others? He conducted the first randomized controlled trial of zinc lozenges to find out. The results were striking. Symptoms resolved much more quickly in those taking zinc, with more than 3 times as many in the placebo group still reporting symptoms at treatment end [2].
And when we look at just the first 24 hours, a really interesting pattern emerges. Just like with George Eby's daughter, many saw their symptoms disappear within hours in the treatment group — 11% within 12 hours and 22% within 24. In contrast, no one in the placebo group had their cold resolve this quickly [2].
But then the story gets complicated. The next two decades saw a pile of contradictory trials, with some showing benefit, and others finding no effect [3].
And here's where the story takes a frustrating turn. Eby and other researchers eventually figured out that the variation came down to chemistry — specifically, what manufacturers were putting into their lozenges alongside the zinc. Some companies added citric acid and sweeteners to improve the taste. The problem? Those compounds bind to zinc ions and neutralize them. The ionized zinc — the form that actually fights viruses — ranged from 100% in zinc acetate lozenges to literally 0% in some commercial formulations [3].
What Should You Actually Take When You Get Sick?
Zinc, saline, honey — the evidence supports specific approaches. Get a personalized health plan that accounts for your immune support needs and overall nutritional gaps.
Get Your Personalized Health PlanEby himself pointed out the problem years earlier — he'd flagged that one of the most-cited negative trials, led by Turner in 2000, used lozenges containing ingredients he'd warned would neutralize the zinc. But the damage was done. That single trial was used for years as evidence that zinc lozenges "don't work" [4].
With this issue sorted out, the picture that emerges is clear. A meta-analysis focused just on trials using zinc acetate found it shortened the duration of colds by 2.73 to 2.94 days [5]. Finnish researcher Harri Hemilä, who conducted the most rigorous analysis of the zinc data, put it bluntly: "The evidence is thus very strong that zinc lozenges may shorten the duration of colds by approximately 33%" [4].
So zinc works — if you get the right formulation. It acts in the throat, where the virus is replicating. But there's another area where a cold virus is rapidly multiplying in those critical first hours: the nose. And it turns out there's a completely different weapon for that.
Saline Nasal Irrigation
For thousands of years, people across South Asia have rinsed their noses with salt water to treat colds. It's described in ancient Indian yogic texts as "Jalaneti" — cleaning the nasal passages [6]. For most of Western medicine's history, the practice was filed under "folk remedy" and largely ignored.
The first crack in that dismissal came from an unexpected corner: Australian woodworkers. Wood dust is a nasal irritant and a known carcinogen to sensitive nasal tissue. The woodworkers were suffering chronic nasal symptoms. A team tested whether rinsing the nose with a saline solution could help. It did. Symptoms improved significantly [7]. But buried in the data was an incidental finding nobody pursued at the time: the workers also reported fewer colds and sore throats [6].
And there was another forgotten clue. Back in 1961, a researcher named Speir had noticed that sodium chloride inactivated viruses in the lab [8].
An ancient practice, a 1961 lab finding, and an incidental observation in woodworkers — three threads that nobody connected. Until Dr. Sandeep Ramalingam, a virologist in Edinburgh, decided to take the folk remedy seriously [9].
Around 2018, Ramalingam and his team published a lab study that finally explained why salt seems to work against viruses — and the answer was surprising. The cells lining your nose and airways already have a built-in antiviral weapon. When a virus shows up, those cells can produce tiny amounts of hypochlorous acid, which is essentially a natural form of bleach, and use it to kill the virus before it spreads. The catch is that to make hypochlorous acid, the cells need chloride ions as raw material [10].
When you're fighting a cold, that raw material can run short. What saline solution does is flood those nasal cells with chloride ions [10]. You're not only washing the virus away. You're resupplying your cells with the ammunition they need to fight it themselves. It's less like rinsing a wound and more like loading a weapon your body already knows how to fire.
With that mechanism in hand, Ramalingam designed a randomized controlled trial to test whether it actually worked in real patients. Participants had to sign up within 48 hours of feeling their first cold symptoms, which is a critical detail, because the earlier you intervene, the more viral replication you can interrupt [6].
The results were impressive. The saline group recovered nearly two days faster than the control group. They used 36% less over-the-counter cold medication. And they were 35% less likely to pass the cold on to someone else in their household [6].
Now, it's worth being honest about the limitations. The ELVIS trial was a pilot study with only 66 participants. And you can't exactly run a blinded trial with this type of intervention, so people knew which group they were in, which can influence how they report their symptoms. Ramalingam acknowledged that a larger trial was needed to confirm the findings [6].
That larger trial came in 2024, and it focused on children. Over 400 children under 6 were given either saline drops or usual care. The saline group had cold symptoms for six days, compared to eight in the control group. And again, fewer household members caught the cold [9].
Honey: The Oldest Remedy
So we have zinc acting at the throat and saline acting at the nasal passages — both targeting viral replication directly. But anyone who's had a bad cold knows that even if you're fighting the virus, the symptoms can still make you miserable. Which brings us to the third piece of the puzzle — and the oldest.
Some of the oldest known medical prescriptions included honey. An Ancient Egyptian papyrus with 900 different remedies mentions honey an incredible 500 times [11]. Hippocrates prescribed honey for coughs and sore throats [12]. Honey has been used across cultures in traditional medicine for centuries [12].
Then modern pharmacology arrived, and honey got quietly shelved. It was a grandmother's remedy. A spoonful of something sweet that probably did nothing. It took until 2020 for anyone to rigorously test what the ancient Egyptians apparently already knew.
A team at Oxford led by Hibatullah Abuelgasim conducted a systematic review and meta-analysis, pooling data from 14 randomized controlled trials involving patients of all ages with upper respiratory tract infections. Compared to usual care, honey improved combined symptom scores, reduced cough frequency, and reduced cough severity. The effects were consistent enough that the researchers concluded honey was superior to usual care [13].
And yet, despite fourteen trials showing a consistent benefit, honey still barely registers as a mainstream medical treatment for colds. Most doctors won't recommend it. It's absent from most standard treatment guidelines. Four thousand years of traditional use and a meta-analysis, and the medical establishment still can't quite bring itself to take a spoonful of honey seriously.
But as the Oxford team's Joseph Lee put it: "Honey is cheap and widely available — many people will probably have some sitting in the cupboard, so it's worth giving it a try before visiting your GP" [14].
There's still a lot we don't know here. We don't know the optimal dose, or whether raw honey works differently from processed honey. But across fourteen trials, in both children and adults, honey reliably outperformed usual care for cold symptoms.
Practical Steps for the First 24 Hours
So let's bring this together into concrete steps we can take the next time we feel a cold coming on.
The first thing — and timing matters here — is zinc. Remember, in Eby's original trial, 22% of people who took zinc were symptom-free within 24 hours. None in the placebo group were. But the trials that show the biggest effects enrolled participants early — within the first 24 hours of symptoms [15].
The practical implication is that we need zinc lozenges already in the house before we get sick. When we feel that first warning sign, we can start them immediately.
The dose that showed benefit in a meta-analysis of zinc acetate trials was above 75 milligrams per day of zinc [16]. And, as we saw, the formulation matters enormously. Look for zinc acetate or zinc gluconate lozenges that don't contain citric acid [3], sorbitol, or mannitol [4], because those compounds bind to the zinc ions and likely neutralize the effect. Generally, the fewer ingredients, the better.
One product that fits these criteria is Cold-Eeze Cherry Zinc Lozenges. In fact, Cold-Eeze was directly inspired by Eby's research — his accidental discovery with Karen eventually led to the development of this product. They use zinc gluconate and none of the ingredients Eby and others have flagged as potentially interfering with zinc's action.
And you might be wondering about the form of zinc here — it's gluconate, not acetate. It appears zinc acetate might be the most efficient form in terms of producing zinc ions. But zinc gluconate has also been found effective. It was the form Eby used in his original experiment, and a 2017 meta-analysis comparing trials that used acetate and gluconate forms concluded that "properly composed zinc gluconate lozenges may be as effective as zinc acetate lozenges" [4].
They are meant to dissolve slowly in the mouth. We don't want to chew them. The whole point is to keep zinc ions in contact with the tissues at the back of the throat, where the virus is replicating. A common side effect is nausea, especially on an empty stomach, so we want to take them after eating. The protocol Eby used in his original study is one lozenge containing 23 mg of zinc every 2 hours while awake [2].
Second — saline nasal irrigation and gargling. This one we can start immediately and continue several times a day throughout the illness. The ELVIS trial used hypertonic saline, which means it's saltier than normal body fluids. You can buy packets that you mix into water, or make it at home. Making it requires roughly 1 teaspoon (or 5-6 g) of non-iodized salt dissolved in a cup of boiled, then cooled water. The procedure is to rinse each nostril, then gargle. The goal is to flood the tissues where the virus is active with the chloride ions our cells need to mount their hypochlorous acid response.
It's worth noting that Ramalingam himself has used nasal irrigation and gargling for over 15 years — this isn't just academic for him [17].
Third — honey. The most common approach in the literature was around a teaspoon of straight honey 30 minutes to an hour before bedtime. But there isn't a well-established protocol here. It won't shorten the infection the way zinc might, but it might make you more comfortable and better able to sleep while your immune system does its work.
None of these 3 is a miracle cure. And we don't have as many large, randomized trials as we might like. But what we do have is significant evidence of real impact. Shortening your cold by a day or two means a lot when it's interrupting your already busy life. And these interventions are cheap, widely available, and carry minimal risk.
Dr. Brad's MicroVitamin contains zinc glycinate to support daily zinc intake — though for acute cold treatment, zinc lozenges dissolved in the mouth (as described above) are the evidence-based approach.
The Frontier
And the science isn't standing still. There are two emerging approaches that could add to this toolkit — though the evidence is still early.
The first is a nitric oxide nasal spray. Nitric oxide is a molecule our bodies already produce — it plays a role in immune defense [18]. A company called SaNOtize has developed a spray that releases sustained doses of nitric oxide directly into the nasal cavity, and the lab results are remarkable. In a 2025 study, the spray inactivated influenza A and B within 15 seconds. It eliminated SARS-CoV-2 within 2 minutes. And — this is the part relevant to colds — it reduced human rhinovirus, the most common cause of the common cold, by over 99.98% within 2 minutes [18].
The catch? Those are just lab results. Clinical trials during COVID showed it could clear viral loads by 95% within 24 hours in real patients — but those trials were for COVID, not the common cold [19]. A large European trial across 7 countries is currently underway testing it against respiratory infections broadly [20]. We don't have the results yet. And currently, the spray is only available in a handful of countries.
The second is povidone-iodine — the antiseptic you might recognize as Betadine. A Phase III trial tested a 0.5% nasal spray in 260 adults with common cold symptoms [21]. The primary endpoint — nasal symptom improvement — did not reach statistical significance. But among people who started using the spray within the first 24 hours of symptoms, there was a striking 40% improvement in overall symptom severity compared to saline. This subgroup had only 29 people, though, which is far too small to draw firm conclusions [21].
The more accessible angle: Povidone-iodine gargle — regular Betadine — is available over the counter in most countries. Japan has included PVP-I gargling in their national respiratory guidelines for years. The evidence for gargling specifically is thinner than for the nasal spray, but it's inexpensive and widely available.
Both of these are worth watching as the research develops. But for now, the strongest evidence sits with the three strategies we've already covered.
Karen Eby survived her leukemia. Her father spent the rest of his career studying zinc and the common cold [1]. That accidental discovery in 1979 — a tired child who wouldn't swallow a tablet — eventually led to the development of Cold-Eeze and helped launch an entire field of research.
The next time you feel that tell-tale scratch in the back of your throat, consider having these tools ready. The evidence says the first 24 hours matter most.
What Should You Actually Take When You Get Sick?
Zinc, saline, honey — the evidence supports specific approaches. Get a personalized health plan that accounts for your immune support needs and overall nutritional gaps.
Get Your Personalized Health PlanReferences
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC185426/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC7173295/
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC5418896/
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC5061795/
6. https://www.nature.com/articles/s41598-018-37703-3
7. https://pubmed.ncbi.nlm.nih.gov/10628043/
8. https://journals.sagepub.com/doi/abs/10.3181/00379727-106-26352
10. https://www.nature.com/articles/s41598-018-31936-y
11. https://wounds-uk.com/wp-content/uploads/2023/02/ccb2d7179b300e517aee7c0782ec5745.pdf
12. https://pmc.ncbi.nlm.nih.gov/articles/PMC3758027/
13. https://ebm.bmj.com/content/26/2/57
15. https://pubmed.ncbi.nlm.nih.gov/28480298/
16. https://pmc.ncbi.nlm.nih.gov/articles/PMC3136969/
18. https://pmc.ncbi.nlm.nih.gov/articles/PMC12846399/
19. https://www.journalofinfection.com/article/S0163-4453(21)00251-6/fulltext
20. https://www.ecraid.eu/news/ecraid-prime-and-sanotize-begin-trial-antiviral-nasal-spray
