Is 1,000 mg of vitamin C safe? What dosage is too much?

Is 1000mg of vitamin C safe? What dosage is too much?

vitamin C needs | side effects | Mega doses | 1,000 mg | food vs supplements

Is a dose of 1,000 mg of vitamin C safe? Yes, you shouldn’t take it for 2 reasons…

According to the Food and Nutrition Board the recommended daily intake of vitamin C, for the majority of people is about 75 – 90 mg.

It’s 70 mg for women and 90 mg for men.

Moreover, smokers should take more vitamin C per day. Why? They require an additional daily dose of 35 mg of vitamin C.

Smokers have increased oxidative stress. A study suggested that drinking orange juice can increase plasma concentrations of vitamin C in humans. Smokers can benefit the most (4).

Additionally, women in pregnancy require at least 85 mg of vitamin C. Furthermore, women in lactation require at least 120 mg. Always consult your health care provider, before taking any supplements.

Consequently, the maximum recommended vitamin C dose of 120 mg is way less than the dose of a pill containing 1,000 mg of vitamin C.

Is a daily consumption of 1,000 mg of vitamin C safe? Pretty safe actually…

Effects of Mega doses of vitamin C

Researchers have treated cancer patients with high dosages of vitamin C (1). Through IVC therapy (intravenous vitamin C), scientists give cancer patients up to 100g of vitamin C. That’s 100,000 mg. 100 times more vitamin C than a dosage of 1,000 mg.

Almost more than 100,000 times the daily vitamin C recommended intake… That’s a lot. So, what happened to these patients?

Regarding cancer, researchers observed:

  • survival beyond prognosis,
  • improvement in quality of life,
  • improved tolerance of conventional therapy,
  • deterioration in clinical condition, in the absence of vitamin C dosage.

The side effects of mega dosages of vitamin C are minimal, say the scientists. Patients experienced symptoms of Jarisch-Herxheimer reaction. This is a reaction of the body to endotoxins produced by the necrosis of harmful cells in the body. Fever, chills, strong body odor, and pimples can happen.

Don’t forget that happened to heavily cancer patients, after mega vitamin C dosages. Symptoms resolved after 2 to 3 hours, after injection with vitamin C.

On the other hand, therapy with high dosages of vitamin C (IVC) may (1):

  • stabilize cancer,
  • reduce the risk of metastasis,
  • remain tumor stable, even aggressive ones
  • disappear breast carcinoma,
  • help on tumor shrinkage,
  • have anti tumor activity in some cases,
  • help patients regain strength, even walking again

Side effects of vitamin C supplementation

Many studies have shown no significant adverse health effects to humans in general, from vitamin C supplementation.

People who may experience some discomfort, are those who have (2):

  • a history of kidney stone formation,
  • iron overload,
  • taken other drugs, as well.

Side effects may be diarrhea, gastrointestinal disturbances due to the osmotic effect of unabsorbed vitamin C, or mild nausea (3).

What dosage of vitamin C is too much anyway?

According to the National Institutes of Health, vitamin C has low toxicity and it’s rather unusual to cause serious adverse effects. Even at high intakes. The maximum dosage of vitamin C for adults should be up to 2,000 mg daily.

It is highly recommended consulting your doctor before taking vitamin C supplements. Especially if you’re taking other medication, as vitamin C supplements have the potential to interact with several types of drugs.

What are the preferred sources of vitamin C?

There is no reason to take vitamin supplements if you eat a healthy whole food plant-based diet. Vegetables and fruits are the only good sources of vitamin C.

You can see analytically the list with the richest foods in vitamin C here.

For instance, kale, broccoli, or peppers are foods particularly high in vitamin C.

In conclusion, is 1,000 mg of vitamin C safe?

In general, the daily consumption of 1,000 mg of vitamin C is pretty safe. There are no side effects for most people. Certainly, people who follow medication should consult their health care provider, before taking any supplement.

We need to boost vitamin C intake. In the winter, vitamin C seems to be beneficial against the flu and common cold. It boosts the immune system.

Moreover, we should take at least 1,000 mg of vitamin C during the summer, as well. Vitamin C naturally boosts collagen production, help us with sunburns and has powerful anti-aging properties.

Certainly, eating foods high in vitamin C is the best way to boost your daily intake. Furthermore, taking a 1,000 mg vitamin C tablet won’t do any harm. But, won’t help you further either, if you don’t follow a healthy diet.


  1. NCBI-PMC: Effects of High Doses of Vitamin C on Cancer Patients in Singapore
  2. NCBI Possible adverse health effects of vitamin C and ascorbic acid.
  3. National Institutes of Health – Vitamin C
  4. NCBI Effect of orange juice intake on vitamin C concentrations and biomarkers of antioxidant status in humans.