Vitamin B₂ (Riboflavin) is an essential micronutrient belonging to vitamins of B-complex group which are water-soluble.
Riboflavin is believed to have an important function in the synthesis and transcription of DNA.
Riboflavin participates in redox (oxidation-reduction) reactions to metabolise fats, proteins and carbohydrates to produce energy.
Riboflavin is one of the coenzymes responsible for the energy release in mitochondria from the fatty acids and glucose.
Riboflavin also helps in the metabolism of toxins and drugs and protects the body from their harmful effects.
In various ways vitamin B₂ functions as an antioxidant neutralising the free radicals and protects the body from their ill-effects.
Riboflavin helps in the growth and maintenance of red blood cells. It also supports the health of white blood cells, which are responsible for immunity and protection from antigens.
Many biochemical processes are brought about by the vitamin B_2.
 Pantothenic acid and folate are converted into neurotransmitters by riboflavin for cognizance and memory.
High serum levels of riboflavin are found to connect to excellent performances in memory tests.
Riboflavin is found to alleviate the conditions responsible for migraine.
Vitamin B₂ is found to be important for the healthy eyes and also may help in prevention of cataracts.
Riboflavin keeps the mucous membrane healthy and its role in the health of hair, nails and skin is well-known.

Deficiency
Taken along with food, riboflavin is absorbed in the small intestine. However absorption in empty stomach is very poor.
Small quantities of vitamin B₂ are stored in liver and kidneys. Excess of riboflavin is lost in the urine. Hence daily intake of this vitamin is necessary.
Loss of proteins from the body can also cause loss of this vitamin. In women during pregnancy and periods, deficiency of riboflavin may arise.
In alcoholics and elderly people with impaired absorption deficiency of riboflavin may occur.
Some of the symptoms of deficiency of riboflavin are, cracked lips, cracked corners of mouth, sores in the mouth, general debility, fatigue, sore tongue and sore throat, eye fatigue, light sensitivity, inflamed mucous membrane, dry skin and iron-deficiency anaemia.

Toxicity
As excess of riboflavin is excreted in urine toxicity is rare. However high doses injected into blood stream may show sensitivity.

Sources
Good sources of vitamin B₂ include milk, yeast, almonds, organ meat, nuts, egg, poultry, fish, leafy vegetables, whole grains, legumes, soybeans and dairy products.