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Overview: Vitamin C supplements are used to increase vitamin C levels. They are available in a variety of forms, including tablets, gummies, and liquids. Vitamin C is usually well tolerated, although high doses can cause diarrhea, nausea, and stomach cramps. Before taking vitamin C supplements, tell your health care provider about all of your health conditions and any medicines or supplements you may be taking.

Uses

What are vitamin C supplements used for?

Vitamin C supplements are commonly used to treat vitamin C deficiency, also known as scurvy, and to prevent or treat low vitamin C levels from various causes. The benefits of vitamin C supplements for other uses are not well defined.

Vitamin C supplements may also be used for other conditions as determined by your health care provider.

How do vitamin C supplements work (mechanism of action)?

Vitamin C supplements contain Vitamin C, also known as ascorbic acid. Your body needs vitamin C to build protein and maintain a healthy immune system. Vitamin C also acts as an antioxidant.

In the United States, most people get enough vitamin C from their diet. It is found in vegetables and fruits, especially citrus fruits and tomatoes. For most adults, the recommended daily intake of vitamin C is 75-90 milligrams (mg). However, some people either do not get enough from their diet or have trouble absorbing it. When this happens, you can take vitamin C supplements to replace what you are not getting from your diet.

How are vitamin C supplements supplied (dosage forms)?

Vitamin C, also known as ascorbic acid, is available as a dietary supplement in various strengths and dosage forms to supplement levels of this vitamin. 

How should I store vitamin C supplements?

You should store vitamin C supplements according to the product label. Most medicines should be kept in a cool, dry location that is away from direct sunlight and out of the reach of children and pets.

Side Effects

What are the most common side effects of vitamin C supplements?

The most common side effects of vitamin C supplements are listed below. These side effects are more likely to occur in people taking more than 1,000 mg daily. Tell your health care provider if you have any of these side effects that bother you.

  • Diarrhea
  • Nausea
  • Stomach cramps

There may be other side effects of vitamin C supplements that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of vitamin C supplements?

While less common, the most serious side effects of vitamin C supplements are described below, along with what to do if they happen.

Severe Allergic Reactions. Vitamin C supplements may cause allergic reactions, which can be serious. Stop taking vitamin C supplements and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use vitamin C supplements?

Allergies to Ingredients. People who are allergic to any of the following should not take vitamin C supplements.

  • Ascorbic acid
  • Vitamin C
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific vitamin C supplement products they stock.

What should I know about vitamin C supplements before using them?

Vitamin C supplements are dietary supplements. They cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep vitamin C supplements out of the reach of children.

If you are using a gummy vitamin C supplement, chew the gummy well before swallowing. If you are using a liquid vitamin C supplement, use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist what measuring device to use.

What should I tell my health care provider before using vitamin C supplements?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if vitamin C supplements are right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Kidney stones
  • Other kidney problems, including dialysis
  • High iron levels, such as iron overload or hemochromatosis
  • Treatment for cancer, including radiation or chemotherapy
  • A history of smoking cigarettes or exposure to secondhand smoke

Malabsorption Syndrome. You may have trouble absorbing vitamin C supplements if you have malabsorption syndrome. Malabsorption means your body is not able to absorb and use the nutrients that you take by mouth or from the foods you eat. Talk with your health care provider about taking a vitamin C supplement and checking your blood levels of this vitamin.

Other Medicines and Supplements. Vitamin C supplements may interact with other medicines and supplements. Before taking vitamin C supplements, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take vitamin C supplements while you are pregnant or trying to get pregnant.

Breastfeeding. Vitamin C supplements pass into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take vitamin C supplements while breastfeeding.

Interactions

Do vitamin C supplements interact with foods or drinks?

There are no known interactions between vitamin C and foods or drinks.

It is unknown if drinking alcohol will affect vitamin C.

Do vitamin C supplements interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking vitamin C supplements.

  • A statin, such as atorvastatin (Lipitor and others) or rosuvastatin (Crestor), which is a medicine to lower cholesterol
  • Chemotherapy, which is a type of medicine used to treat cancer

This may not be a complete list of medicines that can interact with vitamin C supplements. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much of a vitamin C supplement?

If you or someone else has used too much of a vitamin C supplement, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of a vitamin C supplement?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.