Vitamin C Side Effects That May Surprise You

By Arturo Galindo, Cert. Nutritional Therapist

The most important of all vitamin C side effects is "chronic good health". But that's only if you take enough vitamin C of course.

There are also other side effects that you need to be aware when you take vitamin C in large enough doses. Most of these are positive side effects.  A few are nothing more than inconveniences.  

For example, did you know vitamin C can increase the potency of pharmaceutical drugs? This means vitamin C can help you reduce your dependency on drugs. And also avoid other potential harmful side effects.

Vitamin C Side EffectsChronic Good Health is a Side Effect of Taking Enough Vitamin C

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Important:  Ascorbic acid or vitamin C is more than a vitamin.
Why? It regulates many functions in your body to make sure they're doing their best job in keeping you healthy!

What Is a Side Effect?

A side effect is a secondary effect of doing something. This secondary effect can be negative, or it can also be positive.

For example, one positive side effect of drinking enough water is relieve constipation. 

But if you drink too much water you can get headaches, nausea and bloating. In severe cases it can lead to seizures, organ failure and even death. These are the negative side effects of drinking too much water.

The key is to know when you’ve had enough water, before you start taking too much. The only person who can know when you've had enough water is you. You learned to identify the signs that your body gives you to know when to stop. 

Vitamin C Side Effects 

Vitamin C works in the same way as water. You must learn to identify when you’ve had enough vitamin C, before you start taking too much. 

The difference is that Vitamin C is much safer than water. Even if you take too much, you can’t overdose on vitamin C.

And the negative vitamin C side effects are nothing more than a few inconveniences. 

This is because vitamin C is not toxic and experts consider it safe.

One of the vitamin C side effects that you may not want is diarrhea. If you take too much, you get the flush. But a flush or loose stools can help your body in many ways. And the good news is that you can control this. 

Another of the vitamin C side effects is that few people may experience heartburn or stomach cramps because they have sensible stomachs.

But there is a solution to this problem... and if you are one of those few people, you can still get all the health benefits of vitamin C.  

Here are the details.

Vitamin C May Give You the Flush or Diarrhea

Relieve constipation is one of vitamin c side effectsRelieve constipation is one of vitamin c side effects

When your body can’t “hold” any more vitamin C you start to experience gas, “rumbling” stomach and loose bowels. This is your bowel tolerance, or your saturation point. 

If you take too much vitamin C too often, you will get very loose stools. This is a good thing if you suffer from constipation or infrequent bowel movements.

Vitamin C cleanses your body and acts as a laxative in the same way as a bowl of prunes.

This “inconvenience” goes away once you reduce the vitamin C dose. 

Your bowel tolerance is a sign to reduce your vitamin C dose. You need to continue to take vitamin C, but you need less amount and less often. If you're sick, you can "hold" more vitamin C since your body uses it to fight disease. When you are healthy, you need less, and your body can “hold” less.

On a personal note, this is one of my favorite vitamin C side effects. Why?

Vitamin C helps you have regular and predictable bowel movements.

And this means you feel lighter and with more energy.  

I have my vitamin C in the morning on an empty stomach and drink plenty of water. I wait at least 20 minutes before I eat anything. And then my body does the rest.

Vitamin C May Cause Heartburn, Stomach Cramps or Acidity

Heartburn is another of vitamin C side effects for a few peopleHeartburn is another of vitamin C side effects for a few people

Vitamin C is a weak acid that has a low pH value. It's like citric acid in limes or lemons. When vitamin C dissolves in water, it is sour, but it is less sour than citric acid. 

Because of this, your body can tolerate a lot before it affects the body acidity. 

But some people have very sensitive stomachs. If you are one of them, vitamin C can give heartburn or stomach cramps.  

Here's the thing.  Your body regulates the acid balance in the blood. This is the pH level, which is a measure of acidity. An acidity (pH) value of 7 is neutral. The pH of vitamin C is 2.5. The lower the number, the more acid the substance.

As comparison, a Coca Cola has a pH of 2.5, and a minute maid lemonade has a pH of 2.6. 

Other forms of Vitamin C help with stomach acidity.

If you have stomach acidity you can use other forms of vitamin C such as sodium ascorbate to reduce the acidity.  This is ascorbic acid mixed with sodium bicarbonate. 

If you use sodium ascorbate, make sure to eat lots of fruits and veggies to get enough potassium.  

You can also use liposomal vitamin C to help bypass the digestive tract. This form delivers the vitamin C straight to the blood cells and this means no stomach acid problems.

To learn more about the different forms of vitamin C, read my articles about vitamin C supplements.

Vitamin C Eases Pregnancy Complaints

Are larger amounts of vitamin C good for pregnant women? Yes.  Here are some vitamin C side effects during pregnancy: 

  • Improve iron absorption. You need less iron. 
  • Reduce Constipation.  Higher doses of vitamin C can work as a stool softener. 
  • Reduce Backaches. Strengthen ligaments and tendons, and ease pain.
  • Reduce Leg cramps.
  • Reduce Bleeding gums. Strengthen the bond of capillary walls and hold cells together.

My wife is currently pregnant with our third baby. She's in the first trimester and her current daily dose of vitamin C is 8 grams. She also and plans to increase the dose in second and third trimesters.  

Here's some more information about vitamin C during pregnancy. Also, this article talks about supplements to ease pregnancy complaints.

Vitamin C Prevents Negative Side Effects of Vaccines and Increases Effectiveness

Some people experience negative side effects and adverse reactions after a vaccine. Many of these adverse reactions are allergic responses.

But there can be other negative reactions as a result of a compromised immune system.

Vitamin C in large enough doses neutralizes toxins.

This means vitamin C can kill toxins in the body. This includes mercury, thimerosal, or other toxic components that vaccines use. In animal studies, vitamin C protects animals from mercury

Vitamin C also increases the antibody response of the immune system.

You see, the goal of the vaccine is to stimulate an antibody response to the antigens of the vaccine.  In animal studies, vitamin C stimulates the elaboration of antibodies in mammals. Because of this, vitamin C may help vaccines be more effective.

Vitamin C Prevents Negative Side Effects of Other Drugs and Increases Their Potency

If you have a health problem you should see your physician. He’ll probably prescribe a drug for you. Often the drugs are effective in controlling the disease but have side effects that can harm you. And many times, doctors prescribes a second drug to control the side effects of the first drug. 

We've been there.

Drugs are dangerous. That’s the reason most of them are available only with a doctor’s prescription.  Other drugs do not need prescriptions, but they are still dangerous. 

The reality is that you never know when you will have an adverse reaction to a medical drug

Vitamin C is an essential food required for life and good health. It’s safe and nontoxic. And it you take enough, vitamin C can help protect your body from the harmful side effects of drugs.

This is because vitamin C helps increase the potency of other drugs. And at the same time it protects your body.

Vitamin C can help you reduce your dependency on drugs

This is one of the vitamin C side effects that can really improve your health. If you can take less drugs, you can reduce your risk of adverse reactions. This means you become healthier. Here are some examples.

Vitamin C helps control blood pressure.  

Many people, including me and my wife, follow the recommendations of Dr. Linus Pauling. We use vitamin C and the amino acid Lysine to help control blood pressure. It has helped us depend less on blood pressure medication.

And some people have even stopped taking any blood pressure drugs. 

Vitamin C helps treat cancer.

Vitamin C reduces the negative side effects of many cancer drugs and chemotherapy. And at the same time, it increases the potency and effectiveness of drugs and treatments.

For many health clinics, Vitamin C is the preferred cancer treatment since Vitamin C kills cancer cells. An example is the Riordan clinic.

Vitamin C and other drugs.

Vitamin C has helped me take less allergy and pain relieve drugs.  As a result, I now very rarely take any medication.

But when I do, I take enough vitamin C at the same time. This is to reduce the risk of a side effect and increase the drug’s potency.  In this animal study, vitamin C protects mice against acetaminophen damage.



  • Levy, T. (2002) Curing the Incurable - Vitamin C, Infectious Diseases, and Toxins

By Arturo Galindo
Certified Nutritional Therapist

I have used vitamin C and nutrition for over 10 years to end my chronic diseases and help my family stay healthy. Learn about our story.

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