Does Vitamin C Help With Colds – Fact or Fiction?

A girl squeezing an orangeI got a rather nasty case of the common cold last week.

Runny nose, sore throat, mild fever and coughing. You know the drill.

Nothing really newsworthy about that, the common cold is the most frequent infectious disease in humans and the average person gets it several times during the year.

But it got me thinking about the old myth that high-dose Vitamin C can prevent colds.

Does Vitamin C Help With Colds? Fact or Fiction?

This theory was popularized around 1970 when Nobel prize winner Linus Pauling published a book about cold prevention using mega doses of Vitamin C. He used up to 18,000 mg himself, every day (The RDA is 75mg for women and 90mg for men).

At that time, there weren’t really any reliable studies that proved this to be true.

Since then, this has been studied extensively.

Vitamin C And The Immune System

Vitamin C is an antioxidant and necessary to produce collagen in the skin. Collagen is the most abundant protein in mammals, keeping our skin and various tissues tough but flexible.

A deficiency results in a condition known as scurvy, which isn’t really a problem today as most people get enough Vitamin C from foods.

However, it is less known that Vitamin C is also highly concentrated in immune cells and is consumed quickly during an infection (1).

Does it Have Any Effect on The Common Cold?

In the past few decades, multiple randomized controlled trials have examined whether the vitamin has any actual effect on the common cold.

The results have been fairly disappointing.

A meta-analysis that examined 29 trials in a total of 11,306 participants revealed that supplementing with 200mg or more of Vitamin C did NOT reduce frequency of colds (2).

However, there was a tendency for Vitamin C to reduce the severity and duration of colds.

Take Home Message

Basically, if you take Vitamin C, you’ll get just as many colds as you did before but they may be slightly less severe and last for a slightly shorter time period.

Of course, there are other potential benefits of Vitamin C supplementation and there’s a lot of epidemiological evidence suggesting that adequate Vitamin C from foods reduces risk of cardiovascular disease and cancer (3).

Personally I don’t eat a lot of plant foods so my dietary intake of Vitamin C is pretty low, but I do get more than the RDA from my daily multivitamin.


  1. Heya Kris, love the new look.
    Speaking of new: Happy New Year!
    Yeah I take vitamin C about twice every day, for its anti oxidant and cortisol lowering properties.
    I also heard say it’s like a carrier for Iodine, so you absorb it better. Yet anther very good reason for me to make sure of adequate C every time!


  2. Kris,

    I also had a bit of a common cold this past week. Once I noticed the symptoms, I immediately started downing lemon water and it helped a lot. The cold turned out to be very minor and only lasted a couple of days versus when I used to get a cold for a week or so.

    I’ve read that natural sources of Vitamin C are preferable to synthetic sources when it comes to fighting infection and that lemon juice is particularly effective because the Vitamin C is combined with additional antibacterial properties of flavenoids.


  3. Olive Leaf Extract works great to minimize sickness!! I buy the Barlean’s on Amazon. Olive leaf complex, taken a few times a day and I don’t get the awful cold like the family does. It stays very mild and bearable. Great for soothing a sort throat too. Try it! Olive leaf also takes care of intestinal parasites and helps with yeast overgrowth.

  4. My chiropractor does mega doses of zinc (I believe that’s what it is) and it knocks the cold out in about a day. However, it only works if you have your gall bladder. If it has been removed, it doesn’t work.

  5. I think there is no “silver bullet” when it comes to a single vitamin preventing colds, but I think getting optimal amount of high quality vitamins (a full spectra) helps boosting the immune system and thus preventing colds much better (and make them last shorter). Since I started using my current vitamin/mineral/anti oxidant supplement about 3.5 years ago I haven’t had a single cold(!). Prior to that I had bad colds about 2-3 times each autumn/winter, pretty bad ones (tonsillitis and other things).

  6. I take vitamin C and Zinc every day… extra to what is in my multi. I only take one of each, not a mega dose by a long shot, but I think it helps. I used to get one really bad cold a year, plus a couple of mild ones, but now I don’t get the bad one and not so many mild ones, could be the C and zinc, or just could be I’m taking better care of myself generally!

  7. I have not found that any vitamin regimen will significantly reduce the likelihood that I will get a cold. I also do not take ANY vitamins because I prefer to get them from their natural food source.

    Typically, when I do get that start of a cold; scratchy throat, sore muscles, etc., I take mass quantities of Vitamin C. I will consume 1,000 mg an hour in addition to tons of orange juice. If I do this, the next day I will wake up with no symptoms. This isn’t always full proof but it cuts my colds down to probably one a year if that.

    The only other thing I would add to that is getting a good steam to sweat out some of those toxins.

    Thanks for your posts Kris, they are extremely helpful.

  8. I don’t do anything to add Vitamin C to my regimen. Just what I get from the veggies I eat on LCHF and occasional fruits. Yet since adopting this dietary approach I have not had (knock wood) ONE single cold. Prior to this I could expect 5 or 6 in a “good year”, more in a bad one–this was my lifelong pattern. NOT ONE in the past two years!

    A few times I felt like a cold was brewing and I loaded in the bone broth and tea. By the next morning I always felt fine. These have been the healthiest two years of my life.

  9. The thing about Vitamin C is that you need to take very high doses for it to be effective. Niqee’s experience makes sense. Some clinical trials have shown that taking Vitamin C has no beneficial effect on colds, but they have used only moderate doses of 2g or so per day. This is way above the Recommended Daily Allowance (RDA) but still low. The RDA is designed to be just enough to avoid scurvy, nothing more! I have read fascinating information recently about Vitamin C and its health benefits when taken in very high doses: ‘mega doses’ of 20g per day and far more in extreme cases. Vitamin C is also very safe to take in high doses because the body just gets rid of excess amount in the urine. No clinical trials have ever taken place to examine the benefits of megadoses of Vitamin C. Perhaps this is because the pharmaceutical industry funds most trials and it’s not in their commercial interests to find that people could just take megadoses of Vit C instead of buying lots of ‘cold cures’.
    I highly recommend this book (also a Kindle eBook):
    Vitamin C: The Real Story (Hickey and Saul).

    • I do the same as Niqee too. As soon as I start getting the symptoms, I start taking about 2000Mg a day + the fruits that I regularly eat which contain vitamin C. If my wife or kids get a cold, I start this preventively. You really have to do this at the very beginning or right before you develop the symptoms or else it will not work. I find that sleeping lots had more to do with the duration of the cold and the vitamin C has more to do with the intensity.

    • Thomas Johnson says:

      It has been shown that for Vitamin C to stop a cold or flu you need to take many grams/hour until you reach bowel tolerance (i.e. diarrhea) starting as soon as you feel symptoms. If you wait until the infection takes hold you can only reduce the length and severity. It’s possible you may need as much as 100 grams/24 hrs. NO studies have ever been done like this.

  10. “Personally I don’t eat a lot of plant foods so my dietary intake of Vitamin C is pretty low, but I do get more than the RDA from my daily multivitamin.”

    Wow, this inspires confidence in the information you provide!

    • I was doing a ketogenic diet at the time, which tends to be low in Vitamin C.

      I’ve stopped doing it now, get plenty of Vitamin C from foods and stopped taking the multivitamin as well.

  11. Very high doses of vitamin C can cause kidney stones and believe me, once you have one of those so you’ll settle for a cold any day!

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