Vitamin B2 (Riboflavin)

General Info


Vitamin B2 is absorbed from the upper part of the small intestine, and best absorbed when taken with food. Approximately 15 percent is absorbed if taken alone versus 60 percent absorption when it is taken with food. The conversion of riboflavin into its coenzymes takes place in the majority of cells throughout the body, but mainly in the cells of the small intestine, liver, heart, and kidney.

Dietary Origins

The best sources of vitamin B2 are found in liver, and dairy products. Moderate sources include avocados, dark green vegetables, eggs, fish including salmon and tuna, meats, mushrooms, and oysters.


Vitamin B2, Riboflavin, is a water-soluble B vitamin, which is an important factor in oxidative and enzyme dependent processes of the body. It is also essential for the metabolism of carbohydrates, fats, and proteins. Making it essential for normal growth and development, lactation, physical performance, reproduction, and good health. Deficiency is rare because vitamin B2 is readily available in many food sources. However, storage in the body is minimal, and when dietary intake is insufficient, signs of deficiency can occur within one week. Making it essential to be supplied daily.

Toxicities & Precautions


There are no known toxicities or precautions associated with riboflavin.

Functions in the Body

Antioxidant Activity

Shown to have antioxidant activity, both by itself, and as part of the cellular oxidation-reduction reactions.

Energy Production

Plays a role in the conversion of carbohydrates to energy.


Riboflavin is necessary for growth and reproduction of healthy skin, hair, and nails.

Symptoms & Causes of Deficiency

Vitamin B2 deficiencies primarily affect the eyes, skin and mucous membranes of the gastrointestinal tract. Deficiencies rarely occur alone, but most often as a component of multiple-nutrient deficiencies. Cheilosis (kīlō′sis) a classic sign of riboflavin deficiency is characterized by cracks around the corners of the mouth, soreness and burning of the lips, inflamed mucous membranes. Riboflavin deficiency can also affect the eyes, causing burning, itching, reddening, tearing, and eyes that tire easily. Other symptoms that can develop include dry, itchy, scaly skin and scaling eczema of the face and genitals. In severe long-term deficiency, damage to nerve tissue can cause depression and hysteria.

Riboflavin is heat stable, but very sensitive to light. Because it is a water-soluble vitamin, large amounts are lost by evaporation when cooking. Since the vitamin exists in the germ and bran of grains, milling and processing of grains results in large losses. Individuals at greatest risk for riboflavin deficiency include alcoholics, elderly, and premature infants. Women taking oral contraceptives have an increased need for vitamin B2. Individuals with hypothyroidism are likely as well to have what amounts to a riboflavin deficiency.