Vitamin C

Last Updated: September 28 2022

Vitamin C is an essential vitamin with antioxidant properties. It is frequently supplemented to ward off the common cold, though its efficacy is questionable, and likely low.

Vitamin C is most often used for


Vitamin C, or L-ascorbic acid, is a water-soluble essential vitamin. It is a very popular dietary supplement due to its antioxidant properties, safety, and low price.

Vitamin C is often supplemented to reduce the symptoms of the common cold. However, vitamin C is unable to reduce the frequency of colds in a healthy population. An athlete who frequently undergoes intense physical activity can expect to cut the risk of getting a cold in half. Supplemental vitamin C is able to reduce the duration of a cold by 8-14% in any population, when it is taken as a daily preventative measure, or at the beginning of a cold. Though superloading vitamin C (5-10g daily) is said to be more effective, further research is needed to determine the accuracy of this claim.

Supplementation with vitamin C can lower uric acid levels, making it a potential candidate for reducing the risk of gout.

Vitamin C is capable of being both an antioxidant and pro-oxidant, depending on what the body needs. Vitamin C also required for various biological processes, including the synthesis of collagen, L-carnitine, and norepinephrine (aka noradrenaline). These functions mean vitamin C may have beneficial effects on brain health, depression, cortisol levels, pancreatic health, and blood flow. By protecting the testes from oxidative stress, vitamin C may also preserve testosterone levels.

Vitamin C is often supplemented as a way of reducing the risk of cardiovascular disease, however existing evidence suggests it is generally ineffective for this purpose.

What else is Vitamin C known as?
Note that Vitamin C is also known as:
  • Ascorbic Acid
  • Ascorbate
  • L-ascorbic acid
  • 2-(1 2-dihydroxyethyl)-4 5-dihydroxy-furan-3-one
Vitamin C should not be confused with:
Dosage information

According to the WHO, most adults need only 45 mg of vitamin C per day, but more recent research has shown this number to be too low. The minimum has been set at 75 mg for women and 90 mg for men in the U.S., and 95 mg for women and 110 mg for men in the E.U.

Moreover, a 2022 study using 110 mg as its starting number recommended adding 10 mg per 10 kg (22 lb) above 60 kg (132 lb) of body weight.[293]

Any of these numbers are easily attained through the diet, so supplementation of such low doses is usually unnecessary. Higher doses of vitamin C, up to 2,000 mg, are used to support the immune system (for athletes) or reduce the duration of the common cold.

Most studies on vitamin C prescribe one dose per day. The claim that taking 2,000 mg up to five times a day to optimally reduce cold symptoms is not sufficiently tested and requires more evidence.

Join our supplement information course

Enter your email to get a FREE five-day course on supplements. 100% backed by science, we take an independent and unbiased approach to figure out what works (and what's a waste of time and money).

    The only 100% independent company. While everyone sells supplements, we only analyze research.

    Examine Database