Vitamin C (L-Ascorbic acid)

Nowadays, you can see vitamin c everywhere, especially in the drug store. The article here is to better understand this product.

What is L-Ascorbic acid?

L-Ascorbic acid is an antioxidant, also known as Vitamin C (VC), naturally found in food and used as a vitamin supplement. It is a colorless, odorless crystal powder that is easily soluble in water and insoluble in organic solvents. Stable in acidic condition, but will be oxidized under the condition of oxygen, heat, light and alkaline substances in the air.

The chemical structure is similar to glucose and is a polyhydroxy compound. Its two adjacent enol-type hydroxyl groups on the 2nd and 3rd positions in the molecule are easily dissociated to release H+, so it has the property of acid.

Food sources

The main food source of Vitamin C (L-Ascorbic acid) is from fresh vegetables and fruits. The high source in vegetables like pepper, garland chrysanthemum, bitter gourd, beans, spinach, potatoes, leeks, etc. And The fruits like jujube, fresh dates, strawberries, citrus, lemon and so on are high with VC.

It has two forms, L-type and D-type, but the latter has no biological activity. We called Vitamin C in the market is usually the L form. L-ascorbic acid,  which is synthetically produced.


Ascorbic acid is the one of food antioxidants. It is necessary to form collagen, an important protein used to make skin, scar tissue, tendons, ligaments, and blood vessels. It is also essential for the healing of wounds, and for the repair and maintenance of cartilage, bones, and teeth.

Vitamin E and beta-carotene are two other well-known antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals, which are by-products that result when our bodies transform food into energy. The build up of these by-products over time is largely responsible for the aging process and can contribute to the development of various health conditions such as cancer, heart disease, and a host of inflammatory conditions like arthritis. Antioxidants also help reduce the damage to the body caused by toxic chemicals and pollutants such as cigarette smoke.

L-Ascorbic acid vs Ascorbic acid

As mentioned above, there are two types of ascorbic acid: L-type and D-type. L Type can be derived from both natural (in fruits and vegetables) and synthetic manufacturing process (in most other supplements), it is called Vitamin C and has all the benefits, while D has the same antioxidant properties performance but not the vitamin C content and structure of L, and is not used for any form of vitamin supplements.

Although the chemical properties of D-ascorbic acid is same with L-ascorbic acid, but it is molecularly different. It is this molecular difference that makes it impossible for D-ascorbic acid to be synthesized by your body and cannot be used as a vitamin supplement. D-ascorbic acid has no biological activity and cannot called VC.



Chemical FormulaC6H8O6
Molecular Weight176.1
FunctionIt is mainly used to production of various medicines as clinically important material for supplementary cure practice in different sectors. When used as a food additive, it acts as superior and reliable agent in nutrition, antiseptic and flour processing aspects. It also helps enhance the immune system of animals when used in feed additives.
SolubilityFreely soluble in water, sparingly soluble in ethanol (96%).
Melting Pointabout 190ºC, with decomposition


Manufacturing process

The manufacturing process of is from fermentation, two microbial are used, The ‘Black acetic acid bacteria’ is used in the 1st step fermentation. ‘Bacillus megaterium’ and ‘Gluconobacter oxydans’ are used in the 2nd step fermentation. Totally 24 processes are needed to get the finished product- Vitamin C. Below is the brief flow chart and you’ll see how is L- ascorbic acid made and where does it come from fermentation and chemical synthesis.



The benefits including form antibodies and collagen, the repairment of tissue (including some redox); the metabolism of phenylalanine, tyrosine and folic acid; the utilization of iron and carbohydrates; the synthesis of fat and protein; the maintenance of immune function, hydroxyl And serotonin; maintain the integrity of the blood vessels; promote the absorption of non-heme iron and other necessary. Also, it has the benefits of anti-oxidation, anti-free radicals can inhibit the formation of tyrosinase, so as to achieve whitening, blemish effect.

In humans, VC is a highly effective antioxidant that is used to reduce the oxidative stress of ascorbate peroxidase substrates. There are many important biosynthetic processes that also require it to participate.



VC is important for many body functions.

It is involved in the hydroxylation reaction. Hydroxylation is an essential step in the synthesis and decomposition of many important substances in the body. VC must be involved in the hydroxylation process.

Function in hydroxylation reaction

  • Promote collagen synthesis. In the absence of VC, collagen synthesis is impaired, resulting in scurvy.
  • Promote the synthesis of neurotransmitters (5-hydroxytryptamine and norepinephrine).
  • Promote hydroxylation of steroids. Patients with high cholesterol should supplement sufficient amounts of VC.
  • Promote the hydroxylation and detoxification of organic substances or poisons. Vitamin C can increase the activity of mixed-function oxidases and enhance the detoxification (hydroxylation) process of drugs or poisons.

Reduction function

VC can be oxidized or reduced in the body, so it can be used as a hydrogen donor, but also as a hydrogen acceptor, which plays an important role in the process of redox in vivo.

  • Promote antibody formation. The high concentration of VC helps the reduction of cystine in food proteins to cysteine, which in turn synthesizes antibodies.
  • Promote the absorption of iron. It can reduce the hard-to-absorb trivalent iron to easily absorbed ferrous iron, which promotes iron absorption. In addition, sulfhydryl groups such as ferrous iron complex enzymes can also be made active in order to function effectively. Therefore, VC is an important auxiliary drug for the treatment of anemia.
  • Promote the formation of tetrahydrofolate. Vitamin C can promote the reduction of folic acid to play a role in tetrahydrofolate, it also has a certain effect on megaloblastic anemia.
  • Maintain the activity of sulfhydrylase.

Other functions

  • Detoxification. After adding a large amount in the body, it can alleviate the toxic effects of heavy metals such as lead, mercury, cadmium, and arsenic on the body.
  • Cancer prevention. Many studies have shown that VC can block the carcinogen N-nitroso compound synthesis and prevent cancer.
  • Scavenging free radicals. The process by which VC can be converted to semi-deoxy ascorbic acid and dehydroascorbic acid by stepwise electron donation removes superoxide (O2), hydroxyl radical (OH), organic radicals (R*), and organic peroxides from the body. Radical (ROO · ) and other free radicals; tocopherol free radicals reduced to tocopherol, the reaction of ascorbic acid generated by the free radical under certain conditions can be NADH2 system enzymes reduced to ascorbic acid.

Mechanism of action

The metabolism and conversion of vitamin C in the body are still inconclusive, but it can be determined that the final metabolite of VC is excreted in the urine. If the concentration in the urine is too high, the pH in the urine can be lowered to prevent the growth of bacteria, so it can prevent urinary tract infection.

Oxalic acid is one of the metabolites. Its output varies from person to person. An average of 16-64 mg of oxalic acid a day is excreted in the urine. Most people worry that too much oxalic acid can cause stones. In fact, the content of oxalic acid in the body, besides part of them from the metabolism, most of it is from directly intake food, or amino acid food metabolism. It is known from experiments that even if a high amount of VC is ingested, the amount of oxalic acid in the urine does not increase. Therefore, there is no need to worry about the problem of stones.

Vitamin C is excreted through the kidneys, so the kidney has a function of regulating the excretion rate of VC. When the amount in the tissue is saturated, the excretion will increase; when the tissue content is insufficient, the excretion will decrease. Intrahepatic metabolism, excreted in a small amount by the kidneys as prototype or metabolites. When the plasma concentration is greater than 14 μg/ml, the urinary excretion increases. Can be cleared by hemodialysis.



In food

It can be used as nutritional supplements, Antioxidants, Color protection agents in food. As Vitamin C (L-Ascorbic acid) is not sour and soluble in water, it is easy to use. Ascorbic acid is generally used for jams, canned fruits, transparent hard candies, fruit juices and etc. Sodium Ascorbate is used in ham, sausages, fish cakes to fix the flesh color and keep it fresh. If ascorbic acid is used, the pH will decrease and the water retention will be affected. It has the effects of preventing oxidation and stabilizing the color of chilled aquatic products.

In the feed

It can be used in feed additives. Not like Vitamin B series, which used widely in feed than food, Vitamin C is used much in food than feed.

In cosmetic

Its salts are used in a variety of cosmetics and personal care products including makeup, as well as skin and hair care products as antioxidants to slow deterioration caused by exposure to the air and also to control the PH of the finished product.


Side effects

  • Redness and warm feeling of the skin, or flushing
  • Headache
  • Nausea, vomiting, or diarrhea
  • Upset stomach during or after eating
  • Feeling faint

Allergy symptoms

Seldom people are allergic to Ascorbic acid. When taking a vitamin C supplement or a beverage that contains ascorbic acid, such as fortified juices, the allergy symptoms may include asthma, headaches, itching, fatigue, skin rashes, runny nose, sniffling, wheezing and congestion. Common skin allergy symptoms include hives, eczema and general skin itching.

Is VC bad?

Generally, it is safe and not bad but the large dosage may have some side effects:

  • Long-term use of 2 ~ 3g daily can cause scurvy after drug withdrawal.
  • Long-term use of large amounts can cause urate, cysteine, or oxalate stones.
  • A large number of applications (daily dosage of 1g or more) can cause diarrhea, bright red skin, headache, frequent urination (above 600mg daily), nausea and vomiting, and stomach cramps.

Dosage per day

Recommendations for vitamin C dosage by adults have been set by various national agencies:

  • 40 milligrams per day: India National Institute of Nutrition, Hyderabad
  • 45 milligrams per day or 300 milligrams per week: the World Health Organization
  • 80 milligrams per day: the European Commission Council on nutrition labeling
  • 90 mg/day (males) and 75 mg/day (females): Health Canada 2007
  • 90 mg/day (males) and 75 mg/day (females): United States National Academy of Sciences.
  • 100 milligrams per day: Japan National Institute of Health and Nutrition.
  • 110 mg/day (males) and 95 mg/day (females): European Food Safety Authority
US vitamin C recommendations (mg per day)
RDA (children ages 1–3 years) 15
RDA (children ages 4–8 years) 25
RDA (children ages 9–13 years) 45
RDA (girls ages 14–18 years) 65
RDA (boys ages 14–18 years) 75
RDA (adult female) 75
RDA (adult male) 90
RDA (pregnancy) 85
RDA (lactation) 120
UL (adult female) 2,000
UL (adult male) 2,000



Market demand will increase

Global Vitamin C (L-Ascorbic acid) market is expected to witness growth over the forecast period owing to increasing demand from industries including food & beverage, pharmaceuticals, chemicals, personal care and cosmetics. In addition, growing demand for potassium, calcium and sodium salts of ascorbic acid as an antioxidant food additive is expected to drive the market over the next six years. Uncertain raw material supply and resulting price fluctuations are anticipated to hamper the market growth (in 2017 market). Now the market price seems go down to a normal level.

China is the big Vitamin c manufacturer, and almost all VC in global market is from China. Manufacturers and suppliers in China like:

  • DSM
  • CSPC Pharma
  • Shandong Luwei
  • Northeast Pharma
  • Ningxia Qiyuan
  • Zhengzhou Tuoyang

The export quantity from China has increased year by year, with 131,000 tons exported in 2016 and 148,000 tons exported in 2017. However, compared with the domestic total production capacity of 200,000 tons, the industry is still in surplus. Since 2012, the unit price of export has remained at around 3.6 U.S. dollars per kilogram for a long a period of time, resulting in a loss in the entire industry. In 2017, with the government strict control in environment pollution and other conditions, the price of Vitamin C increased a lot even more than USD10/kg.

From January to December of 2017, China exported 148,796 tons of vitamin c, increased of 13.4% compared with that in 2016. From January to December of 2017, the amount of China’s exports was US$ 879,741,000, an increase of 104.1% than 2016.

China Vitamin C Export Quantity from 2012 – 2017


China Vitamin C Export Amount (1000USD) from 2012 - 2017

China Vitamin C Export Amount (1000USD) from 2012 – 2017


China Vitamin C Export average price from 2012 – 2017



Leave a Comment

Send this to a friend

Hi, this maybe interesting you: Vitamin K3 Menadione Nicotinamide Bisulfite (MNB), this is the link: