Combating the common cold: What herbals work?

Please note that this research is for treating, and not preventing, colds and flu.

Evidence-based literature search

When it comes to assessing supplements and natural therapies, I use only a tiny handful of resources that I consider trustworthy. All are certified by the Health on the Net Foundation as sources of trustworthy medical information. These sites review only the best, most unbiased research, which usually means the gold standard of randomized, placebo-controlled trials.
I strongly recommend that everyone use HONCode's search engine for medical advice, especially about supplements. Here are my favorite medical resources and their evaluations of therapies for the common cold:

• The Natural Medicines Database, a fantastic resource for doctors, doesn't rank any therapies as "effective" or even "likely effective" in its review of the common cold. The database’s next ranking, "possibly effective," lists andrographis, vitamin C, zinc lozenges, echinacea and elderberry.
• The Encyclopedia of Natural & Alternative Treatments has a common cold review that concludes that zinc lozenges, echinacea and andrographis all have fair evidence to shorten a cold and lessen symptoms. Vitamin C, ginseng and garlic may help prevent colds, but they do not ease symptoms.
• The Cochrane Library, a well-respected independent review board, looked at common cold treatments and found poor evidence for most supplements, including vitamin C bursts. However, it did find that zinc lozenges at a total daily dose of more than 75 milligrams during a cold can quicken recovery time. Cochrane said there was "weak evidence" for echinacea. Cochrane also reviewed a popular European herbal treatment for colds, pelargonium sidoides. It concluded that this herb may help with symptoms of acute rhinosinusitis and the common cold in adults, "but doubt exists."
• The National Center for Complementary and Integrative Health, the official government agency, has a review of common cold products and supports oral zinc for treatment. It finds no strong benefit for vitamin C, echinacea or probiotics.

Let's look at the supplements that have the most evidence:

Zinc

This seems to have the most support, especially in daily amounts greater than 75 milligrams and in lozenges containing zinc gluconate or zinc acetate. Some good studies show that zinc lozenges can reduce coughing, runny nose, headache, sore throat and overall time of illness. But side effects are common, especially nausea and a bad taste in the mouth. Also, definitely do not use zinc nasal sprays. There’s clear evidence they can cause permanent loss of smell. The data suggest you should stick with lozenges and not pills. I see a few brands of zinc lozenges with up to 30 milligrams each, which at three times a day would help. I also see a few popular brands with lozenges that contain only 5 milligrams of zinc. This seems far too low to help. I wouldn't advise giving children zinc lozenges.

Echinacea

This is probably the supplement you've heard most about, and the evidence is encouraging -- but not totally clear. There are a few well-designed studies that have found some species of echinacea can reduce the symptoms and duration of a common cold, at least in adults (not children). But on the flip side, many studies have shown no benefit. The best evidence is for products that include the above-ground portion of E. purpurea, not the root. Overall, it's very difficult for me to recommend echinacea. Studies have used multiple regimens with drops, pills and teas, and with many types of echinacea in different combinations of root and plant. Here's a useful list of test results from ConsumerLab showing which brands in the U.S. have proper amounts of the herb.

Andrographis peniculata

An Indian herb very popular in Ayurvedic medicine and now in Europe, I think this actually has some good evidence.  A handful of double-blind, placebo-controlled studies have shown benefit in reducing the duration and severity of cold symptoms, especially coughing. An excellent meta-analysis of herbals from Germany showed significant improvement in severity and duration of a cough, especially when the herb is taken in liquid form. The usual amount seems to be 48 to 500 milligrams of above-ground parts of andrographolide, usually divided into three doses a day. You can find a good list of andrographis brands on iHerb.com. I keep reading about a Swedish patented combination with eleutherococcus and sambucus (called Kan Jang Plus), but I don't see it sold anywhere in the United States.

Pelargonium sidoides

This is an interesting herbal. It’s very popular in Europe and perhaps should be more popular here. That same German meta-analysis I mentioned above found strong evidence that it helped with cough, fevers and sore throat. The analysis said this applied to children as young as 1, although the German independent Institute for Quality and Efficiency in Health Care says pelargonium sidoides shouldn't be used for children under 6. The Cochrane Library also reviewed this herb and concluded that it may be effective in easing symptoms of acute rhinosinusitis and the common cold in adults, “but doubt exists." As with andrographis, the liquids and syrups were better than tablets. I see on iHerb a series of pelargonium products called Umcka with good reviews.

Probiotics

There’s actually pretty good evidence that taking probiotics for months, especially over the winter, can markedly improve both the frequency and the severity of colds for kids and for adults (as does vitamin D). That's great news! But for symptom relief during a cold, there is scant evidence. I couldn't find one good study for this, and none of the resources above recommends probiotics as treatment. 

Vitamin C

Here's another super popular supplement that many people swear by. But again, the evidence isn't conclusive. The few studies that do show a benefit show only mild improvement. Still, it seems safe for adults and children, and the evidence is even stronger as a preventive during the cold seasons.

My bottom line

For immune boosting, don't forget the most important advice: Get a good's night sleep, eat foods high in anti-oxidants and stay well hydrated. 

I think it's appropriate for adults (not kids) to try some of the above supplements -- and the sooner, the better, within 24 hours of symptoms. 

Confronting a cold

For what it's worth, here's my plan for myself and my wife the next time we get a cold: We're going to continue our usual vitamin C-plus-zinc bursts, usually using Airborne effervescent tablets, three times a day. Emergen-C and Wellness Formula are similar. All three have a ton of vitamin C, some zinc and an assortment of herbals, many of which are mentioned above.

I'm also adding 400 milligrams of andrographis twice a day and pelargonium; and I'll continue doubling up on my probiotic supplement, despite the lack of evidence. (One note: Last week my wife tried andrographis for the first time and had a horribly itchy rash for days. I was fine.)

Guidance for kids 

In general, I'm hesitant to advise using any of these herbals for children under 6 years old, and I remain cautious about what I use with my own kids, both under 4. I still like probiotics during a cold. I’m also a big fan of honey for coughs for all ages above 1 year, which studies show works better than any OTC syrup. I'm encouraged by the European studies using pelargonium and also ivy/primrose/thyme syrups, some of which are partially included in American brands like Zarbees. 

For more age-specific advice, please look at the recommendations in my previous article about curing a cough.
 
For more information about this topic, and for other advice on wellness, you can read my blog, MyFamily Health Guide, or check out my Facebook page at Bainbridge Baba Doc.

Do you have a favorite herbal remedy? Let us know in the comments below.