High Dose Vitamin C “Flush”: Safe or Risky?

by Sarah Pope MGA | Affiliate linksComments: 50

high dose vitamin c
Ever since Linus Pauling popularized the practice of taking high dose vitamin C orally to combat the common cold in the early 1970s, some within the alternative health community have enthusiastically touted the benefits of a “vitamin C flush” or ascorbate cleanse. 

I’ve always been skeptical of taking large doses of isolated vitamins for any purpose. Using nutrients like drugs seems a short-sighted approach to healing. I am particularly dubious of large doses of ascorbic acid separated from the beneficial flavonoids and other co-factors present in whole food forms of Vitamin C.

How to Take High Dose Vitamin C Orally (Vitamin C Flush)

The primary goal of flushing the body with high doses of vitamin C is to achieve rapid detoxification or speed recovery from an illness. Note that it is quite different from a niacin flush, which also assists cleansing. One alternative practitioner once recommended high dose vitamin C when my toddler had a fever. I didn’t take this advice for reasons covered later in the article.

Here’s the process of in a nutshell:

  1. In the morning ideally, on an empty stomach, take 1000 milligrams of ascorbic acid powder mixed into 4 ounces of filtered water. Buffered ascorbate powder, which is ascorbic acid bound to minerals like calcium, magnesium, or potassium, is another option. If you have a sensitive stomach, buffered ascorbic acid is the better choice.
  2. Repeat every half hour until you make a mad dash for the bathroom with an urgent case of watery diarrhea. A loose stool is not sufficient. Keep going until a large amount of liquid is rapidly evacuated from the body. At that point, do not take any more ascorbic acid that day.
  3. Drink plenty of filtered water, homemade electrolyte beverage, and bone broth to prevent dehydration.
  4. Optional step. If desired, cut the dosage by at least half and continue to take every four hours for the next 1-2 days to continue the detoxification process. The goal is to maintain loose, but not watery stools. If stools are too loose, cut the dose back further before continuing.
  5. Some practitioners suggest doing a flush once a week for 3-6 months.

How Much Ascorbic Acid is Needed for a Flush?

The average person requires 4-8 1000 mg doses of ascorbic acid or ascorbate powder for the initial bathroom run to occur.

See what I mean about high dose vitamin C being used as a drug instead of nutrient? I had a college acquaintance who essentially did the same thing with over the counter laxatives from the pharmacy in order to fit into her skinny jeans!

Ascorbate Cleanse Benefits?

Detoxification with high doses of ascorbic acid will quickly resolve any vitamin C deficiency that exists. That is the only benefit I can identify from this natural remedy. Whether it is worth the stress and strain of forcing a rapid and violent excretory response is doubtful!

I can report that in two decades raising 3 children, I have never found the need to use this type of flush for any reason. There are simply too many other options that accomplish the same thing much more gently!

Forcing violent diarrhea on yourself let alone a child seems excessive!

Vitamin C Flush Risks

Warning: Some people get a migraine-like headache from ingesting large amounts of plain ascorbic acid in such a short period of time. An ascorbic acid induced headache can last for 1-2 days and does not easily respond to over the counter pain medication. It can be quite debilitating.

Bloating and a flare-up of hemorrhoids after a flush are potential side effects as well.

Whole food vitamin C does not typically cause the same problem. In fact, it’s much harder to accomplish an ascorbate flush using whole food vitamin C. This is because the ascorbic acid is bound with synergistic co-factors not present in plain ascorbic acid. These substances have a mitigating effect on the violent detoxification response. They also allow you to take far fewer milligrams per day to achieve optimal vitamin C status

Doesn’t this tell you something right there?

Whole Vitamin C Compared to Ascorbic Acid

Here are some of the best whole food vitamin C products on the market and how much ascorbic acid each contains.

*For reference, 1/2 tsp of plain ascorbic acid powder contains roughly 2,500 mg of ascorbic acid.

As you can see, the plain ascorbic acid powder is a minimum of 10 times more potent than the best whole food vitamin C supplements on the market!

Why is isolated ascorbic acid so different from whole food vitamin C?

The reason is that it is synthetic at best and GMO at worst!

Isolated ascorbic acid powder must be made in a factory. Whole vitamin C from food always comes with synergistic substances that enhance its many benefits. Using plain ascorbic acid or ascorbate to do rapid detoxification is indeed like using a drug.

GMO Vitamin C

Another problem is ascorbic acid from a genetically modified source. GMO corn is the usual culprit. If this is the case, then the risk of ingesting glyphosate residue is very real. The residue exposure is very small, to be sure, but if you have the choice to not consume it and use a nonGMO whole food Vitamin C, then why not? Glyphosate is a suspected carcinogen and at the very least, damages beneficial gut flora even in minute amounts. The EU Parliament recently voted to ban it by 2022. The UK is considering a similar measure. (1)

Conventional farmers, if you recall, heavily and repeatedly spray GMO crops with Roundup. They are genetically modified to withstand the onslaught of the herbicide as they are “Roundup Ready”.

It’s true that dozens of nonGMO crops like wheat are sprayed with Roundup too (primarily for desiccation purposes just prior to harvest). However, conventional farms douse GMO corn, soy, sugar beets, and canola much more heavily and repeatedly.

Health Risks from High Dose Ascorbic Acid

While a Vitamin C flush is a short term process, there are many folks who get somewhat addicted to the detoxifying effects that are so easily achieved. Hence the popularity of those Emergen-C packets which are available everywhere now – even at gas stations!


500+ mg of plain ascorbic acid a day may increase the risk for arterial plaque buildup. Another study showed that people taking ascorbic acid supplements may be more prone to gallstones. Although ascorbic acid was discovered in the 17th century and is critical to human health, its complete role still remains a mystery with many contradictions in the research studying its beneficial health effects! (2)

The bottom line is that its best to stick with natural, whole food forms of vitamin C. Avoid high doses of isolated ascorbic acid or buffered ascorbic acid (ascorbate) devoid of beneficial co-factors.

Safer Alternatives to a Vitamin C Flush

There is no doubt that detoxification helps with healing and recovery from illness. However, forcing the issue with megadoses of synthetic vitamin C does not seem wise.

Here are 4 suggestions for safer detoxification options. They will work just as well as a vitamin C flush without the violent intestinal response!

  • Epsom Salt Baths: Epsom salt is magnesium sulfate crystals. Soaking the feet or the entire body in a warm bath with a small number of Epsom salts added will gently encourage elimination without stress and strain. In fact, any regular program of detoxification bathing would be helpful. Be sure to buy the best Epsom salt by looking for proper labeling.
  • Coffee Enemas: The word “enema” is a repulsive word for some. However, the process is ancient and the detoxification results profound. See the linked article for more detail. If using an enema bag is off-putting, ready to use, saline enema bottles are available for just a few dollars at the pharmacy. Be sure to get a brand without chemical additives.
  • Castor Oil Pack: Oral castor oil is another way to invoke a violent diarrhea response similar to a vitamin C flush. Sometimes pregnant women use it to start labor without induction drugs (not recommended!). When used externally on the abdomen, however, the results are gentle but still very effective.
  • Cleansing Herbs: A simple detox tea (this one is very effective) can gently invoke an elimination response without violent diarrhea.

Benefits of High Dose Vitamin C

We’ve established that using high dose vitamin C for basic detoxification on otherwise healthy people may not be such a great idea. If a person is gravely ill with few options for recovery, however, high dose vitamin C therapy especially intravenously can prove helpful.

For example, emerging evidence is that high doses of ascorbic acid or ascorbate can play an important role in holistic cancer therapies. (2)  High doses of C are useful in conjunction with conventional treatments as well. For example, researchers have already published research concerning how ascorbate/ascorbic acid effectively fights tumor cells. In addition, the number of successful case studies continues to increase where high dose vitamin C treatment proved helpful when the right protocols were used.

I hope this article gives you pause before jumping on the Vitamin C flush bandwagon. While high dose vitamin C definitely has its place as holistic therapy for the critically ill, healthy people simply seeking to detox should use with caution. Fast is not necessarily better, which is why I’ve always said “no” to this natural remedy.

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