Difference Between Ascorbic Acid and L-ascorbic Acid

Ascorbic Acid vs L-ascorbic Acid

Ascorbic acid is an organic compound, which can act as an acid. Organic acids essentially contain hydrogen and carbon with another element/s. Other types of most common organic acids are acetic acid, lactic acid, formic acid, citric acid, etc. These acids have a –COOH group. Therefore, they can act as proton donors. Ascorbic acid is present in citrus fruits. For example, lime, lemon, oranges can be considered as citrus fruits.

Ascorbic Acid

Ascorbic acid is also a naturally occurring organic acid. It is present in humans, plants and micro organisms. It has the molecular formula of C6H8O6. This is a white color solid, but sometimes may appear in a slight yellow color too. The yellowish color represents the low purity level of ascorbic acid.   Ascorbic acid has the following cyclic structure with acidic groups. 


Ascorbic acid is soluble in water and other polar organic solvents. When dissolved in water, it forms a mild acidic solution. When loose proton from a hydroxyl group is bonded to vinyl carbon, the molecule is stabilized by resonance stabilization. This stability of deprotonated conjugate base of ascorbic acid makes it more acidic than the other hydroxyl groups. Ascorbic acid is an antioxidant like citric acid. Therefore, it reacts with the oxidants of the reactive oxygen species, to yield harmful species. For example, when ascorbic acid reacts with hydrogen peroxide, it forms hydroxyl radicals, which can damage the important molecules in the cells. Ascorbic acid is a reducing agent. When exposed to air, it reduces oxygen to water. When light and metal ions are present, these reducing reactions speed up. In the synthesis of ascorbic acid, glucose becomes the reactant. Most of the animals can synthesize ascorbic acids within their bodies.  Glucose to ascorbic acid conversion takes place in the liver and for that, the enzyme L-gulonolactone oxidase is required. But some animals like bats, primates, guinea pigs and birds cannot synthesize ascorbic acid due to lack of this enzyme. For humans also this is the case. So they should fulfill the ascorbic acid requirement from their diets.

L-ascorbic Acid

L-ascorbic acid is also known as vitamin C, and this is an essential nutrient for humans. This is the form of ascorbic acid, which animals and humans should take into the body, if they cannot synthesize ascorbic acid. This is the l-enantiomer of the ascorbic acid and the d- enantiomer has no significant role in biological systems. As mentioned above, this is the compound which acts as a reducing agent and an antioxidant in biological systems. They are important for the synthesis of collagen, carnitine, neurotransmitters, tyrosine, etc. Further, it is needed as a cofactor for some of the synthesis process. Lack of vitamin C causes the disease called scurvy. Symptoms of this disease are brown spots on the skin, spongy gums and bleeding from mucous membranes.


What is the difference between Ascorbic Acid and L-ascorbic Acid?

• L -ascorbic acid is the l-enantiomers of ascorbic acid.

• L -ascorbic acid is the compound abundant in biological systems than the d-ascorbic acid.

• Some organisms can synthesize l-ascorbic acid inside their bodies.