Nontraditional Treatments for a Cold: Do They Work?
Here's your guide to whether things like Vitamin C, ginger and zinc actually help fight the common cold
No doubt you've heard about, or used, non-traditional treatments for the common cold, like American ginseng. Or maybe you've wondered what works and doesn't. Here's a guide to what science and research show about which of these are safe and effective.
What Is the Common Cold?
The Mayo Clinic defines the common cold as a viral infection of the nose and throat (upper respiratory tract) that adults can catch two or three times per year. There's no cure nor vaccine, and antibiotics are useless in treating colds.
"Our belief in a medicine can influence how effective that medicine is."
So, what can you do to prevent or treat the more than one billion colds that, according to the National Center for Complementary and Integrative Health (NCCIH), Americans get each year?
Prevention and Traditional Treatments
Treatment has traditionally relied on prevention and managing symptoms. As we've learned all too well from the coronavirus, hygiene is important in avoiding viruses — wash your hands, don't touch your face and use hand sanitizer.
If you do catch a cold, symptomatic treatments include making yourself comfortable for the seven to 10 days it can take a cold to run its course.
The Mayo Clinic recommends you stay hydrated by drinking water, juice, clear broth or warm lemon water with honey. You can take something to relieve pain, like acetaminophen, ibuprofen or aspirin, as well as something to relieve stuffiness, like saline nasal drops or sprays. A saltwater gargle can help relieve a sore or scratchy throat. And over-the-counter cough and cold medications may relieve symptoms, too.
The more popular non-traditional treatments for the common cold include vitamin C, echinacea, zinc, American ginseng, garlic and probiotics. And while there's some good news on this front, there's also bad news: some of these treatments have scant research to back them up.
Vitamin C won't necessarily help the average person prevent a cold. According to he NCCIH: "an evaluation of the large amount of research done on vitamin C and colds (29 studies involving more than 11,000 people) concluded that taking vitamin C doesn't prevent colds in the general population."
However, according to the Mayo Clinic, some studies show, "taking vitamin C before cold symptoms start may shorten the length of time you have symptoms." But it appears that if you wait to take vitamin C until after you start to feel symptoms, the supplement won't affect the length or severity of your cold.
"The placebo effect is very powerful. Just believing that a particular supplement can help you recover faster may in fact help you recover faster."
This is another one of those herbs where the results are a mixed bag. The Mayo Clinic found that "some studies show no benefit. Others show some reduction in the severity and duration of cold symptoms when taken in the early stages of a cold."
One factor that may have contributed to inconsistent study results could be that different kinds of echinacea may have been used in different studies.
According to the NCCIH, "they may contain different species of the plant and may be made from different plant parts." Something else to consider: "They also may be manufactured in different ways and some products contain other ingredients in addition to echinacea."
Besides possible variations in the product itself, the NCCIH found that "at least 24 studies have tested echinacea to see whether it can prevent colds or relieve cold symptoms. A comprehensive 2014 assessment of this research concluded that echinacea hasn't been convincingly shown to be beneficial." In other words, "the overall evidence for clinically relevant treatment effects is weak."
Dr. Lise Alschuler, Associate Director of the Fellowship in Integrative Medicine at the University of Arizona Andrew Weil Center for Integrative Medicine, has seen some benefits with zinc.
"Zinc supplementation has been shown in many clinical trials to shorten the duration of the common cold," she explained. "This is most effective for this purpose when consumed as a lozenge."
The NCCIH echoed Alschuler's assessment, however it specified that a lozenge should be taken "within 24 hours of initial symptoms and taken for a time period of less than two weeks."
Still, like with the other supplements, there's some disagreement over whether zinc can reduce the length of a cold. The Mayo Clinic says that "research has turned up mixed results about zinc and colds. Some studies show that zinc lozenges or syrup reduce the length of a cold by about one day."
In addition, the Mayo Clinic said, zinc has "potentially harmful side effects." It suggests speaking with your primary care physician before using zinc to prevent or shorten a cold.
American Ginseng (Panax Quinquefolius)
According to the NCCIH, several studies evaluated the use of American ginseng in preventing colds and "a 2011 evaluation of these studies concluded that the herb has not been shown to reduce the number of colds that people catch, although it may shorten the length of colds."
Alschuler says American ginseng can, however, improve aspects of the immune system and possibly reduce inflammation. All of which she says, might help reduce the risk of common cold.
"Clinical trials involving herbals, botanicals, probiotics and other types of dietary supplements typically include too few participants to draw strong conclusions about their efficacy for the condition under study."
Alschuler reports that in one large clinical trial, "garlic appears to cut the incidence of the common cold in half." A 2001 U.K. study in the journal Advances in Therapy concluded that "the results overwhelmingly favored the supplement as a preventive measure" and a 2012 article in Clinical Nutrition showed that "supplementation of the diet with aged garlic extract may enhance immune cell function and that this may be responsible, in part, for reduced severity of colds and flu."
But a 2014 evaluation of the research on garlic and the common cold concluded that "there isn't enough evidence to show whether this herb can help prevent colds or relieve their symptoms" and more studies are needed.
Alschuler says there are benefits to this supplement: "Probiotics support optimal immunity and may therefore lower the risk of infections, improve response to vaccinations and shorten the duration of respiratory tract infections, especially among elderly adults as shown in multiple clinical trials."
Backing that up is a 2021 review in the journal Healthcare which looked at eight clinical trials and found that "certain probiotic strains were better than a placebo in lowering the incidence or number of older people experiencing acute upper respiratory tract infections."
However, not all probiotic strains were efficient, and not all studies reported significant outcomes. The authors concluded that "more high quality large-scale, properly controlled clinical studies focusing on older people are warranted."
The Placebo Effect
Then there's the placebo effect.
"The placebo effect is very powerful. Just believing that a particular supplement can help you recover faster may in fact help you recover faster," explains Dr. Brent A. Bauer, director of research at Integrative Medicine and Health at the Mayo Clinic. "So, if a patient of mine finds that, for example, vitamin C really seems to nip cold symptoms in the bud, I don't argue against it. In general, it's a much better approach than trying to use antibiotics for a viral problem."
Alschuler also agrees that the placebo effect can play a "beneficial role" in treating the common cold. But, she adds, "if a placebo effect is present, that does not preclude the fact that the herb or supplement is also working. Our belief in a medicine can influence how effective that medicine is."
Like many health professionals, Bauer cautions that, "if you're considering taking a natural product, review it with your primary care team to make sure it won't interfere with your medications or medical conditions."
Inconsistencies and Caveats
So why is the data on all this so inconsistent? The reality is, several conclusions about alternative treatments use the words "may" or "could" when evaluating effectiveness and the long-term effects of some of these non-traditional cold treatments have not been sufficiently studied.
"Clinical trials involving herbals, botanicals, probiotics and other types of dietary supplements typically include too few participants to draw strong conclusions about their efficacy for the condition under study," says Dr. Craig Hopp, deputy director of the Division of Extramural Research at the NCCIH. Also, he says, "different formulations or extractions of the same ingredient can be highly variable in their composition and concentration."
That can make it hard to compare the results of studies that use different preparations of the same product. Because of these variables, Hopp says, it's often "challenging to make any definitive statements one way or the other."