7 Tips for Preventing Colds and Flus | Chris Kresser
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7 Tips for Preventing (And Shortening) Colds and Flus


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Cold and flu season is upon us—but that doesn’t mean you have to suffer. Check out these tips for supercharging your immune system and boosting your resilience.

preventing a cold
Knowing how to prevent a cold or the flu is your best chance for a misery-free season. istock.com/AlexRaths

Conventional wisdom holds that there’s not much you can do to prevent colds and flus—and even less you can do to treat them. Of course you could get a flu shot, but research suggests they aren’t nearly as effective as many believe. OTC remedies like antihistamines, decongestants, and NSAIDs can suppress some of the symptoms associated with colds and flus, but they do nothing to prevent them or shorten their duration. And while antibiotics may be necessary in certain cases (e.g. a cold that progresses to a severe sinus infection, though even this is debatable), they aren’t useful for treating the viral infections that cause colds and flus.

Cold and flu season beating you down? Check out these 7 tips for boosting your immune system.

But here’s the good news: there are, in fact, several steps you can take that will strengthen your immune system and not only decrease the chances that you’ll get sick in the first place, but help to reduce the intensity and shorten the duration of any cold or flu you do get. Instead of just suppressing symptoms, these tips will actually improve the function of your immune system as well as attack the viruses themselves.

#1: Load up on Immune-Boosting Nutrients

There are several micronutrients that are essential for immune health. Many Americans don’t get enough of these nutrients through their diets. But even if you are getting enough, taking additional amounts of them when people around you are sick, or if you’re already sick, can be a big help. These include:

  • Vitamin C. Liposomal forms are best absorbed. I suggest one teaspoon once a day on an empty stomach for prevention, and one teaspoon twice a day for treatment. If you’re using ascorbic acid, take 1,000–4,000 mg/d, up to bowel tolerance.
  • Vitamins A & D. Both of these fat-soluble vitamins are important for immune health, but here’s a little-known fact: research suggests that they are only effective for preventing/reversing colds and flus when taken together. This is why I’m such a proponent of cod liver oil: it contains natural forms of both A & D in a synergistic blend. I recommend Extra Virgin Cod Liver Oil from Rosita as my preferred cod liver oil product. For more information, read this article. You can purchase EVCLO here.
  • Selenium. Selenium helps to balance and regulate the immune system. Most Americans get enough in their diet, but taking a little extra during cold and flu season can help. I suggest 200 mcg/d 3-4 times a week. Note: I do not recommend long-term, continuous selenium supplementation because it has been associated with increased risk of prostate cancer in men.
  • Iodine. Iodine also plays an important role in immune health, and many Americans don’t get enough of it. Ironically, this is especially true for health-conscious people that have removed iodized salt from their diet. The only significant sources of iodine in the diet are sea vegetables, fish heads, and dairy (especially pasture-raised dairy). If you’re not eating these foods regularly, you may want to supplement with about 1 mg per day of iodine in the form of kelp capsules. Note: some people with autoimmune thyroid disease cannot tolerate iodine even in this relatively low amount, so exercise caution if you have Hashimoto’s or Graves’.
  • Zinc. Zinc is another immune-boosting nutrient that many people don’t get enough of. If you like oysters, they are your best bet for meeting zinc needs through diet. You can also take 30 mg/d of zinc picolinate or zinc gluconate for short periods when you feel you’re fighting something.

#2: Drink Fresh Ginger Tea

Ginger is a potent anti-viral substance that prevents the adhesion of viruses to the upper respiratory mucosa.

If you drink the concoction I recommend below at the first signs of sickness, you can often fight it off successfully. But—and this is a big “but”—you have to drink it at or near the strength I suggest, or it won’t be effective. Some people find this difficult to do, because ginger is so intense, but if you can handle it your immune system will thank you.

Also, while it’s possible to do this without a juicer, it will take a lot longer. You can get pretty good juicers now for less than $100, so if you or someone in your family suffers from frequent colds/flus, a juicer is a worthwhile expense (and of course it has many other uses).


  • Juice (or grate on a fine setting) 1–2 pounds of ginger; place juice in a jar and refrigerate
  • Place 2–4 ounces of ginger juice in a mug with the juice of one-half lemon and a large tablespoon of honey (honey is also anti-viral). I recommend Beekeeper’s Natural honey. Add 1/8 teaspoon of cayenne pepper and 6 ounces of hot water.
  • Drink 2–6 cups of this a day, sipping slowly throughout the day

#3: Wash Your Hands

Maybe you already know this, but studies have shown that frequent hand-washing is one of the most important things we can do to protect ourselves during cold & flu season. Wash your hands every time you arrive at a destination while out and about, and first thing when you get home.

#4: Take Elderberry Syrup

Elderberry is one of the most effective botanicals for strengthening immune function and preventing colds and flus. Take 1 teaspoon twice a day if you feel like you’re coming down with a cold or flu—and continue taking it if you do get sick.

#5: Take Immune-Boosting Herbs

There are several botanicals that have a potent immune-boosting effect. I recommend the following blend for prevention during cold season:

  • Mix equal parts astragalus, cordyceps, and rhodiola in tincture form. Herb-pharm is my favorite brand.
  • Take up to 1/4 teaspoon 3x/d for prevention, and 1/2 teaspoon up to 6x/d if you’re already sick.

Note: since astragalus, cordyceps, and rhodiola are “immune boosting” botanicals, people with autoimmune diseases that involve an overactive immune response should exercise caution and speak with their health-care practitioner before using them.

#6: Take Anti-Viral Herbs

If you’ve finally succumbed to a cold or flu despite your best efforts, there are a number of anti-viral herbs that can be helpful. If you want to go deep on this topic, I strongly recommend Stephen Harrod Buhner’s excellent book, Herbal Antivirals: Natural Remedies for Emerging & Resistant Viral Infections. But if you just want to cut to the chase, here’s the formula he recommends for treating mild influenza and colds:

  • Mix 2 parts lomatium, 2 parts red root, 2 parts licorice, 1 part isatis (all in tincture form).
  • Take 30–60 drops mixed with 1–2 ounces of water each hour until condition improves. You may have trouble finding some of these botanicals locally, but you can get them fairly easily online.

#7: Rest

Of all of the recommendations, I suspect most people will have the hardest time with this one. In our crazy, hectic world, rest is simply not valued—but it’s absolutely necessary when battling a viral infection is consuming a lot of your energy.

Of course it’s not always easy to take time for yourself, especially if you have young children (I know this firsthand!), but even a few short rest periods throughout the day can make a big difference when it comes to supporting your immune system.


Join the conversation

  1. I’ve been taking Vitamin D for about 3.5 years and haven’t had the flu or a cold in all that time. I used to average 2 bad colds/flu twice a year.

  2. Chris
    Thanks for the plethora of useful and interesting information and knowledge you supply through your website and emailings.
    I have recently started taking a selenium supplement so it was striking that you mentioned only taking selenium supplements on a limited basis; how long is the flu season? it’s often hard to tell.
    PS I live in Hawaii


  3. Thank you for the article Chris, very insightful as always .. quick question : how about garlic ? many paleo / ancestral resources place garlic ( fresh , raw , organic ) in the top 3 of most effective anti-viral, anti-biotic natural remedies .. interesting you did not include it here .. I got sick lately with flu-like symptoms , and between a few small garlic chunks 3 times a day , and ginger / turmeric tea with Hanuka honey a few times a day, I was good as new in 2 days .. interested on your thoughts. Thanks much.

  4. I have been trying to give my 9 year old daughter elderberry syrup as a preventative measure. 1-2 teaspoons a day for a month. I’ve header that doing it twice a year can help boost the immune system. 2.5 weeks into the course, she got sick. Got better within 3 days … and got sick again 2 days later. Hmmm … doesn’t look like elderberry syrup is working that great for her. I have used Nature’s Way Sambucus, if that matters.

  5. I have rarely been ill for more than 24 hours while using elderberry extract. I have been using it at first exposure or first sign of not feeling well on the schedule you mentioned above, for 2-3years now. Symptom severity is very much decreased and all symptoms have been gone in less than 2 days. Of course, proper nutrition, rest, and fluids are key in conjunction with the syrup or extract.

  6. Chris, great article as usual, thank you! Couldn’t agree more about sleep, but, in my experience, one hugely important item has been added to my list: plain WATER, and lots of it.
    My whole life I’ve gotten multiple colds yearly. I’ve never been a water drinker, at least I wasn’t until a few years ago when a biologist friend asked how much plain water I was drinking during one of my bouts, and my answer was none other than via tea, coffee, etc. She explained that abundant water keeps the nasal and oral membranes well hydrated and better able to fend off infections.
    Since then, religiously I drink year-round 75-100% of my body weight in water ounces daily. Major difference! I’ve not had even one cold since then!
    So my personal experience is sleep is #1 and water is #2!

  7. Hi Chris,
    I am a big fan of your work and I’ve been a reader for years – going all the way back to when you were still in school and blogging as the Healthy Skeptic.
    I really don’t want my comment to come off as rude or as a know-it-all, but I would suggest that you consult with an herbalist before posting an article full of mistakes and subpar advice. For example…

    1. Elderberry syrup is great for preventing a cold. One teaspoon twice a day may be an appropriate dose for a small child but is nowhere near the dose needed for an average weight adult. If you feel like you have something coming on already then an even larger dose is needed. More like a tablespoon every 30-60 minutes.

    2. It’s sort of a misnomer to say that herbs like astragalus and cordyceps are “immune boosting”. While it is a good idea for anyone with complicated health problems to consult with a practitioner there is absolutely no evidence that astragalus and cordyceps can’t be used for people with autoimmunity issues. How do I know this? I am a clinician and I regularly see those herbs help people in my practice who have autoimmune issues. Are they beneficial for all people or for all types of autoimmune issues? Of course not, but that is more the exception than the rule.

    The other issue I have with this recommendation is that the form of administration (tincture) is not ideal and again the dose is really low.

    There are other issues with the herbal recommendations but I’ll leave it at that.

    I am a big fan of your writings because they cut through a lot of garbage and offer great advice. However, this article really fell short of that in regards to the herbal recommendations.

    I am a registered professional herbalist with the AHG and I have been in clinical practice for 6 years. I am also the author of the Herbal Cold Care course. I’d be happy to help you with future articles to support your level of high standards.


    PS I wanted to send this to you privately but your contact page only offered support for digital programs and supplements.

  8. Another significant consideration not mentioned yet, is an environmental factor: the type of heat being used in the home. I know for myself, and many others I’ve spoken with over the years, forced air heat, ‘central’ heat, seems to be the worst for most people; and certainly seems to contribute to more frequent respiratory issues; including generally weakening the immune system from the stress of breathing dried-out air, filled with dust, other icky stuff, and depleted of oxygen. Many have found that living / working in environments with healthier heating, like radiant (hot water) baseboard heat, have drastically reduced winter illness. Obviously, changing one’s heating system is not an option for most people, (and not as easy as taking certain supplements) but it is a significant factor; and things can be done to mitigate the negative impacts of it, especially during a period of illness: using an air filter, keeping the air more humid, have healthy plants in the sleeping room, etc. Air quality is a fundamental aspect of health, especially when sick.

  9. I have found that cod liver oil is great at keeping me well and when I feel something coming on I add 4-5 drops of grapefruit seed extract to my water. It’s bitter so you have to do it in a 32 oz or larger cup/glass for it to be somewhat tolerable. You can add honey to sweeten it. Works like a charm at preventing bacterial infections. I haven’t had the same amount of luck from a viral cold though if I do end up getting one. We have kids so it’s inevitable I won’t be successful every time. I look forward to trying some of these tips listed here. Thanks Chris and commenters!

  10. Great article! Wondering if gargling with salt water or oil pulling would help. And ditto with using neti pot to cleanse sinuses…

  11. The ginger/lime/honey/cayenne mixture is an absolute winner. I have been battling bouts of bronchitis over the last year and finally I found something that knocked it out. I’m a believer.

  12. Fantastic post. Just wondering if the herbs mentioned above are safe for my four year old or even for an infant (possibly in different doses). Also, are the herbs mentioned safe for me while I’m nursing?


  13. Movement! I am amazed at how a long walk (and stretching) at the onset of a respiratory illness can halt it in its tracks with all that lymph drainage and the delivery of oxygen.

  14. Thanks for the great info 🙂 Could you please comment more on what Liposomal vitamin C is and what brands are best?

  15. Would these recommendations help for cold sores (viral). I haven’t had one for 20 years and boom I have one now. I think it was a facial treatment I had that stimulated the virus. Anyway, it’s on my chin. That is where my initial episode was – following a nerve from my ear to my chin. That first episode was horrible and I never want it to happen like that again. So I’ve been reading that too much amino acid Arginine could trigger/awaken the virus. Ironically I had been taking Ancient Earth minerals with amino acids (for the first time) when it started. Do you think this could be part of the cause? From what I understand I should try L-Lysine to counteract the L-Arginine. Want to do everything to keep this mild.

    • My husband is a lifelong on and off cold sore sufferer and ditto for me but instead canker sores. The biggest causes we have found for flare-ups are immune deficiency, with lack of sleep being the most important factor contributing to that. Stress is related too, since it can impact immunity, partially because it usually impairs quality or quantity of sleep. (I also sometime get them if I accidentally injure the skin in my mouth or on my tongue.) So number one, get LOTs of sleep. Number 2, we both take large doses of l-Lysine continuously, whether or not we have sores, and then we double the dose if we feel one coming on. With all of the things we have tried in our lifetimes, l-Lysine is the only thing we have found that is preventative (aside from adequate sleep) and effective in healing them too. Like most things, the key is to be proactive when you feel one coming on. We take 1-3 grams per day total (in 2-3 doses during the day) and I try to take them before meals or away from food. Interestingly, while taking 2 g per day, but stopped during the recommended break before a blood test, I did a NutrEval blood test and it showed me still deficient in Lysine! So my functional med doc told me to go to 3 g per day. I also think it’s hereditary. My father is a lifelong sufferer and so is 1 of my 3 brothers. I hope this helps.

      • Susan, thank you for your helpful insights. I will be trying l-Lysine 500mg twice daily to help heal. I am also doing an OTC cream. I really need to find a good functional health practitioner! I agree that sleep is so important and I strive to get around 8 hours every night. Stress in my life is low to moderate at the moment. I do believe a laser facial treatment I had about a week ago triggered this. I don’t think I will be doing that again 🙁

      • As a lifelong sufferer of canker soars I wanted to share how I got rid of them-I started making my own toothpaste. I read that there is an ingredient in commercial toothpastes that may cause them so I started making my own and haven’t had one since. Once in 5 months I got that first sign I might get one (used to get 1 a month), rinsed with 50/50 peroxide and water and it was gone the next day. Canker soars are no fun and making your own toothpaste is really easy!!

        • Same here.. lifelong canker sufferer. I found out by trial and error what the ingredient was in toothpaste that caused it. Sodium lauryl sulfate. Find a toothpaste without it. I no longer get canker sores now. Hope that helps someone.

  16. Chris,

    You seem to be a pretty evidence based guy. Obviously vitamins are helpful, but could you please list some evidence or any type of study or any proof to believe elderberry or herbal viral supplements work? I think it’s important if you’re making recommendations

    • In my experience, virtually nothing in the field of nutrition can ever be undeniably, scientifically “proven”, and you’re wasting your time trying. For any study you find that ‘proves’ something, there will be others that refute it.
      However, evidence that falls short of definitive proof is still evidence.

      • Fair enough Stan. You did polarize my stance from asking for any shred of evidence to your statement of irrefutable evidence. I think it’s very reasonable to ask for some kind of evidence, even if it’s only 20-30 case studies. Unfortunately, the statement you made that nothing can be proven has made millionaires out of many snake oil salesmen. Hydroxylcut and other supplements that had proven results turned out to be damaging to the point of death and organ failure.

        When we move to making recommendations to take supplements from a place of authority alongside having profit motive, I believe it’s fair for the consumer to ask why? And then to ask for some reasons that have some semblance in reality.

        But maybe Ive just learned to much about the supplement market? Some will take these statements with blind faith and spend hundreds of dollars a year. I would like to see a reason why especially done by independent parties (those who don’t profit off the sale of books or supplements)

        • I completely agree. I think part of the issue is that some herbs are known as traditional remedies, but haven’t necessarily been tested in RCTs. So there may be some in vitro testing showing that some herbal extract has antiviral activity, but we don’t know how that translates to humans outside of anecdotes. (I don’t actually know which of the listed herbs have RCTs, but most have in vitro evidence.)

          Traditional use of a herb does have some weight too, but it could be wrong or even harmful as well. I think it’s important to note that just because something is a natural and traditional herbal remedy does not necessarily mean it is safe. People need to do their research, and it would be very helpful if articles like this had links to that research.

          There was a time when doctors felt that antibiotics helped fight colds, because as far as they could see, when they prescribed them, the cold would be gone in a few days. What they didn’t account for is that colds tend to run their course in a few days, and would have been over without the antibiotic. This is why we need good quality evidence and not just anecdotes (for all meds and supplements, not just the herbal ones).

          In the meantime, zinc lozenges and Vitamin A/D have some good evidence, and honey or other food-type remedies are pretty safe. (Cayenne is lovely for clearing sinuses.)

    • The best proof is in trying it out yourself. Elderberry syrup can be made at home easily and cost effective, there are many recipes online. It won’t hurt to try it, I know folks who remember eating elderberry syrup on pancakes when they were kids…daily (it’s a food).
      Elderberry is great for prevention and at the onset (but not once your sick), the elder flowers (which is the blossom before it becomes a berry) is good for fighting of heat conditions such as a fever, especially when mixed with peppermint it helps push out the heat and resolve while fighting illness.

      Source; I’ve been treating myself and kids using herbs and foods for the last 10 years!