It’s that time of year! The temps dip and viruses get the best of us. There are so many cold “cures” lurking on the internet but how many of them have research behind them? Take a dive into the evidence behind common cold cures and learn what to do to reduce your risk!

First, I want to put a basic disclaimer out there that I am not a medical doctor and am not trying to provide medical advice. I am simply summarizing the research I’ve found on different strategies that have been promoted as curing the common cold. This blog is never a replacement for working individually with your health care providers. 

When I surveyed my Instagram community about this topic, so many people said they wanted to see a blog post on it. And many messaged me to tell me about their method of preventing colds that they swear works. If you and your health care team have devised methods of preventing colds that work for you, go for it. But remember that a lot of stuff floating around on the internet isn’t evidence-based. 

First we’ll start with reliable methods for preventing the common cold. Then we’ll dig into the research on supplements!

Proven Strategies for Preventing the Common Cold

Proper Nourishment

Before you jump to supplements, make sure you’re eating a wide variety of nutritious foods. Simply meeting your nutrient needs (not surpassing them with supplements) can go a long way in keeping your immunity functioning in peak condition. 

Being deficient in nutrients can put you at greater risk for getting a cold. 

Protein, vitamins A, B6, C, D and E, folate, copper, iron, selenium and zinc are particularly important. You can ensure proper nutrient intake by eating balanced meals and snacks. If you’re vegan, you likely need to supplement. 

If you need help ensuring a balanced intake of nutrients, consider working one-on-one with a registered dietitian! You can learn more about working with me here. 

RELATED: How to Get All Your Nutrients as a Vegan

Adequate Sleep

Sleep is when your body does very important repair work. Here is some research detailing how sleep impacts the adaptive immune response. 

Adults need 7 to 9 hours of sleep every night. Not 5. Not 6. If you’re not getting 7 to 9 hours of sleep every night, it’s time to make a change. Consider taking a good hard look at your schedule and commitments and see what needs to come off your plate so you can prioritize sleep. 

RELATED: Yoga for Better Sleep

Frequent Handwashing

Perhaps the easiest, most affordable and accessible thing you can do to prevent getting a cold is washing your hands!

Coming into contact with the cold virus is kind of inevitable. But that doesn’t automatically mean you’ll get sick! If you avoid touching your face and wash your hands often, you can significantly reduce the odds of letting the virus into your body.

Do you know how to properly wash your hands? Lather them up good and scrub for at least 20 seconds before rinsing and drying.

If dry skin is holding you back from washing your hands, get a good moisturizer! Here are my top winter skin care picks. 

Staying Away from Sick People

This may seem like common sense but people who are sick need to stay home. And if they’re out and about, it’s up to you to avoid them! 

If friends or family are sick and want to get together, you can kindly suggest they stay home and rest instead. 

And if YOU are sick, it’s your responsibility to stay home and not spread the sickness. 

Research on Supplements for the Common Cold

Two of the main resources I’m using to evaluate research on this topic are the Natural Medicines Database and ConsumerLab.com, both of which give a review of the available evidence on a variety of supplements. I’m also using PubMed, which is a free search engine for research published all over the world.

Keep in mind that with the plethora of research published (and often low standards for getting something published), you may be able to find a research study to “prove” just about anything. Just because you may have seen some research supporting something doesn’t mean that method is evidence-based or safe. Repeated studies in a variety of populations with large sample sizes is needed before any firm conclusions may be drawn. Animal, in vitro and ex vivo studies should not be used to determine the effectiveness of something in humans. I could go on and on about research but I’ll stop there!

Remember, the supplement industry IS NOT REGULATED. The U.S. Food and Drug Administration DOES NOT APPROVE supplements before they go to market. Talk with a dietitian to learn about which supplements, if any, are the best options for you.

RELATED: The Truth about Dietary Supplements

Echinacea

Natural Medicines Database:  Echinacea is rated as “possibly effective” for the common cold. There are some studies showing that taking echinacea soon after the onset of a cold might have a tiny positive impact. However, other studies showed that when adults were experimentally infected with a cold virus, echinacea didn’t help. 

ConsumerLab.com: There is relatively consistent evidence that echinacea can help people recover from colds more quickly and can reduce symptoms while sick. They caution against taking echinacea throughout cold season and state that there isn’t consistent evidence to suggest that echinacea helps prevent colds. 

Pubmed.gov: I found 130 studies using “echinacea and common cold” search terms and filtering to research in humans. Of these, only 21 were clinical trials. Three of which were published in the last 10 years. 

Several trials failed to find a positive impact of echinacea and one even found that it could increase risk of ear infections in children. 

A 2011 randomized controlled trial found “for the subgroup who believed in echinacea and received pills, illnesses were substantively shorter and less severe, regardless of whether the pills contained echinacea,” giving merit to the placebo effect.

Conclusion: Evidence for echinacea is conflicting but seems to be most consistent for treating a cold when taking right away, rather than preventing it. The placebo effect may play a role in its effectiveness. 

Note that echinacea interacts with some enzymes in the body which can impact drug metabolism. Always talk to your physician and dietitian before starting any supplements. 

Elderberry

Natural Medicines Database: While there are a couple trials showing some impact of elderberry on the flu (rated as “possibly effective”), there is “insufficient reliable evidence to rate” the effectiveness of elderberry for the common cold. 

ConsumerLab.com: Very limited evidence found for the use of elderberry in treating the common cold.  

PubMed.gov: I found 15 human studies published on elderberry and elderberry syrup. One was published in 2001 and found that when participants experiencing flu-like symptoms received 15 milliliters of elderberry syrup four times a day for 5 days, their symptoms got better 4 days earlier than those receiving a placebo.

A 2016 trial resulted in reduced cold symptoms and shorter duration of sickness among air travelers who took elderberry capsules versus placebo. 

A 2019 meta-analysis found that elderberry supplementation reduced upper respiratory symptoms (I could only access the abstract so can’t provide any more detail).

Conclusion: Emerging research shows promise for the use of elderberry in treating the common cold but there is not enough evidence to recommend it at this time. 

Note that elderberry may interact with some enzymes in the body which can impact drug metabolism. Always talk to your physician and dietitian before starting any supplements. 

Vitamin C

Natural Medicines Database: Vitamin C is rated “possibly effective” for the common cold. They note there is “substantial controversy” over the effectiveness of vitamin C for treating the common cold. Some research has found that taking high doses of vitamin C orally might decrease the duration of cold symptoms by 1-1.5 days in some people, while other studies have found no effect.

ConsumerLab.com: Taking a high-dose vitamin C supplement (500 milligrams twice daily – no more than 2,000 milligrams per day) during cold season may slightly reduce the risk of getting a cold but it does nothing once you already have a cold. 

PubMed.gov: I found 494 studies using “vitamin c cold” search terms and filtering to research in humans. Just 83 of these were clinical trials, five of which were published within the last 10 years. 

A 2013 Cochrane review (Cochrane reviews are gold-standard systematic reviews) concluded, “The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified… Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them.”

Conclusion: High-dose vitamin C supplementation may reduce duration and severity of the common cold in some people. There can be side effects with high doses of vitamin C (such as cataracts and kidney stones), which may not be worth the small benefit. 

Vitamin C interacts with lots of drugs, notably coumadin, statins and estrogens. Always talk to your physician and dietitian before starting any supplements. 

Oil of Oregano

Natural Medicines Database: No research on oil of oregano and colds or immunity in humans.

ConsumerLab.com: No double-blind, placebo-controlled studies have been done on oregano.

Pubmed.gov: I could not find a single study on oil of oregano and colds or immunity in humans.

Conclusion: There is a lack of evidence for the use of oregano in preventing or curing the common cold and cannot be recommended at this time. 

Note that oil of oregano can interact with anticoagulant/antiplatelet and diabetes medications. It can also inhibit absorption of iron and zinc. Always talk to your physician and dietitian before starting any supplements. 

Zinc Lozenges

Natural Medicines Database: Zinc is rated as “possibly effective” for the common cold. Several studies have found that zinc lozenges can help treat the common cold by reducing the duration of symptoms. Positive results were found in adults taking zinc gluconate or zinc acetate lozenges providing 9 to 24 milligrams of elemental zinc per dose every 2 hours while awake, starting within 48 hours of symptom onset for a total daily dose of at least 75 milligrams. There is conflicting evidence on zinc lozenges preventing colds.

ConsumerLab.com: Several trials have found that zinc lozenges result in significant reduction in severity and duration of cold symptoms when taken within first 24 hours of symptom onset, particularly nasal congestion, sneezing, scratchy throat and cough.

PubMed.gov: I found 59 studies published using “zinc lozenges cold” search terms and filtering to research in humans. Just 17 were clinical trials, one of which was published in the last 10 years (which was a case study, so not worth much weight). 

A 2011 systematic review found there to be some benefit from high-dose zinc lozenges but more research was needed to form firm conclusions. A 2016 individual patient data meta-analysis found zinc lozenges reduced cold symptoms by 2 to 3 days, but more research is needed on ideal composition and frequency of the lozenges. 

Conclusion: Zinc lozenges, when taken as soon as cold symptoms arise, may help reduce the duration of a cold. 

Note zinc interacts with the drug cephalexin and people on this drug should not take zinc. It can also interact with other drugs, including antibiotics and diabetes drugs. Always talk to your physician and dietitian before starting any supplements. 

*Also note that nasal gels containing zinc have been associated with temporary and permanent loss of smell and should be avoided. 

This was a long post but this topic deserves it! Colds are super common and it’s important that we invest in proven strategies rather than those with little to no reliable research behind them. Wishing you a healthy season!