Skip to content
Vitamins & Supplements

Vitamins

Vitamin B complex

Reviewed August 2026 · How we write these articles

B-complex vitamin supplement tablets
B-complex dietary supplement tablets Image: Ragesoss / Wikimedia Commons (CC BY-SA 3.0)

Vitamin B complex is a supplemental combination of B vitamins which are essential to the body. The vitamin B-complex group includes B1 (thiamin), B2 (riboflavin), B3 (niacin and niacinamide), B6 (pyridoxine), B12 (cobalamin), folic acid or folate, pantothenic acid, biotin, choline, inositol, and PABA (para-aminobenzoic acid). All of the above are water soluble, and play a key role in several bodily functions, such as protein, fat, carbohydrate, and mitochondrial energy metabolism; maintenance of the liver, skin, hair, mouth, and eyes; plus so much more, which will be covered thoroughly within the following paragraphs.

Vitamin B is found in liver, grain, and other food sources. Vitamin B deficiency can cause beriberi, digestive disturbances, degeneration of the sex glands, and neurological problems. Excessive doses of some B vitamins can also cause nervous system damage. Symptoms of B vitamin deficiency can include oily or scaly skin, upset stomach, headaches, anxiety, moodiness, and heart diseases.

Vitamin B-Complex plays many important roles in the body. Vitamin B complex improves the body's resistance to stress. Aids in digestion, promotes good muscle tone, healthy skin. Vitamin B complex reduces muscle spasms, leg cramps, hand numbness and helps regulate blood pressure. Vitamin B complex is involved in an extremely large and important group of metabolic functions in the human body, such as energy production, Interco versions of one substance to another, detoxification, nerve transmission, blood formation, synthesis of proteins and fats, the production of steroid hormones, the maintenance of blood sugar levels, the maintenance of appetite, the toning of muscles, etc. Combination products can simplify the process of taking individual B vitamins for a range of ailments including alcoholism, depression, diabetes, hair problems, lupus, multiple sclerosis, and stress.

It is needed to counter the effects of stress, and bolster the glands (especially the adrenal glands which become easily exhausted when subjected to stress). B-complex is beneficial for healthy hair, skin and nails, red blood cells, antibody production, prevention of muscle cramps and spasms, and elasticity of body tissues.

Vitamin B1 (thiamin)

Vitamin b1 is absolutely essential to several bodily functions. Thiamine is a coenzyme for the decarboxylation of pyruvate and the oxidation of alpha keto-glutamic acid. Thiamine aids the nervous system and is essential for the functioning of important enzymes. These enzymes have vital roles in the processes that make energy available in the body. Thiamine is essential for the transmission of certain types of nerve signal between the brain and the spinal cord. Depression, poor memory, muscle weakness and stiffness, nerve tingling, burning sensation and numbness, tiredness, headache, loss of appetite and nausea are some of the symptoms and signs of thiamin deficiency.

Vitamin B2 (riboflavin)

Vitamin B2 (riboflavin) is a water-soluble vitamin that supports energy metabolism and biosynthesis of a number of compounds through its coenzyme forms, flavin adenine dinucleotide (FAD) and flavin adenine mononucleotide (FMN). Riboflavin is also required for activation and support of activity of vitamin B6, folate, niacin, and vitamin K. Riboflavin is important to energy metabolism (processing nutrients like protein, fat, carbohydrate and alcohol that have calories to a form of energy that the body can use - ATP), normal eyesight and healthy skin. Riboflavin is vital for normal reproduction, growth, repair and development of body tissues including the skin, hair, nails, connective tissue and immune system. Severe riboflavin deficiency is rare and often occurs with other B vitamin deficiencies.

Vitamin B3 (niacin)

Vitamin B3, also known as niacin, niacinamide, or nicotinic acid, is one of eight water-soluble B vitamins. Vitamin B3 is required for cell respiration, helps in the release of energy and metabolism of carbohydrates, fats, and proteins, proper circulation and healthy skin, functioning of the nervous system, and normal secretion of bile and stomach fluids. Vitamin B3 plays an important role in ridding the body of toxic and harmful chemicals. It also helps the body make various sex and stress-related hormones in the adrenal glands and other parts of the body.

Nicotinic acid (vitamin B3)

Nicotinic acid is a B vitamin essential for the normal function of the nervous system and the gastrointestinal tract. Nicotinic acid is used to lower levels of cholesterol and other lipids (fats) in the blood. Cholesterol is made naturally in the body and is absorbed from the food we eat. Nicotinic acid given in drug dosage improves the blood cholesterol profile, and has been used to clear the body of organic poisons, such as certain insecticides. High-dose nicotinic acid also increases serum levels of high-density lipoprotein cholesterol (HDL-C) and decreases serum levels of lipoprotein.

Nicotinamide (Vitamin B3)

Nicotinamide is a form of vitamin B3 that may preserve and improve beta cell function. Nicotinamide is essential for growth and conversion of foods to energy. It has been used in diabetes treatment and prevention. Nicotinamide, via its major metabolite NAD++ (nicotinamide adenine dinucleotide), is involved in a wide range of biological processes, including the production of energy, the synthesis of fatty acids, cholesterol and steroids, signal transduction and the maintenance of the integrity of the genome.

Vitamin B4 (adenine)

Vitamin B4, also known as adenine, is one of the two purine bases used in forming nucleotides of the nucleic acids DNA and RNA. Adenine forms adenosine, a nucleoside, when attached to ribose, and deoxyadenosine when attached to deoxyribose, and it forms adenosine triphosphate (ATP), a nucleotide, when three phosphate groups are added to adenosine. Adenine is a purine. Purines are six-membered rings attached to five membered rings. When adenine is attached to DNA, it forms a bond with another molecule called thymine, a pyrimidine, on the other side of the DNA strand.

Vitamin B5 (pantothenic Acid)

Pantothenic acid comes in three forms, and it is alternately known as vitamin B5, panthenol and calcium pantothenate. Pantothenic acid is involved in a number of biological reactions, including the production of energy, the catabolism of fatty acids and amino acids, the synthesis of fatty acids, phospholipids, sphingolipids, cholesterol and steroid hormones, and the synthesis of heme and the neurotransmitter acetylcholine. Pantothenic acid is integral to many of the activities of enzymes in the human body. It is necessary for the manufacture of energy from both sugars and fats in the system as well as the utilization of other vitamins.

Pyridoxine (vitamin B6)

Vitamin B6, also known as pyridoxine, is an essential vitamin to aid in the formation of healthy red blood cells and supports more vital bodily functions than any other vitamin. A water-soluble vitamin, vitamin B6 is needed to release energy from the food we eat. Vitamin B6 or pyridoxine is a coenzyme for enzymes involved in amino acid metabolism. Deamination, transamination, and decarboxylation of amino acids are required for synthesis, oxidation, and degradation of critical amino acid derived molecules that participate in hematological, neurological, humoral, and inflammatory processes.

Folic acid (vitamin B9)

Folic acid works closely with vitamins B6 and B12 as well as the nutrients betaine and S-adenosylmethionine (SAMe) to control blood levels of the amino acid homocysteine. Vitamin B9 folic acid has a direct effect on lessening depression. It helps regulate sleep, and appetite. Folic acid is crucial for proper brain function and plays an important role in mental and emotional health. Folic acid is the synthetic form of this vitamin that is found in supplements and fortified foods. Folic acid deficiency is the most common B vitamin deficiency.

Cyanocobalamin, cobalamin (vitamin B12)

Vitamin B12, also called cyanocobalamin or cobalamin, is one of eight water-soluble B vitamins. Cyanocobalamin is considered the most potent vitamin and is one of the last true vitamins that has been classified. Vitamin B12 is an especially important vitamin for maintaining healthy nerve cells and it aids in the production of DNA and RNA, the body's genetic material. Vitamin B12 also works closely together with vitamin B9 (folate) to regulate the formation of red blood cells and to help iron function better in the body. Cyanocobalamin deficiency can cause a range of symptoms including fatigue, shortness of breath, diarrhea, nervousness, numbness or tingling sensation in the fingers and toes.

Orotic acid (vitamin B13)

Pangamic acid (vitamin B15)

Amygdalin (vitamin B17)

Inositol (vitamin Bh)

Inositol is part of the vitamin B-complex. It is required for proper formation of cell membranes. Inositol affects nerve transmission and helps in transporting fats within the body. Inositol differs from inositol hexaniacinate, a form of vitamin B3. Inositol is necessary for the formation of lecithin and functions closely with a B complex vitamin, choline. Inositol is primarily used in the treatment of liver problems, depression, panic disorder, and diabetes. It also aids in the breakdown of fats, helps in the reduction of blood cholesterol, and helps to prevent thinning hair.

L-carnitine (vitamin Bt)

L-carnitine, an amino acid derivative, is found in nearly all cells of the body. L-carnitine transports long-chain fatty acids across the inner mitochondrial membranes in the mitochondria, where they are processed by beta-oxidation to produce biological energy in the form of adenosine triphosphate or ATP. L-carnitine is synthesized in the human body, chiefly in the liver and kidneys, from the essential amino acids L-lysine and L-methionine.

Niacin, vitamins B6 and C, and iron are involved in its biosynthesis. There are at least two major functions of L-carnitine. Long-chain fatty acids require L-carnitine to transport them across the inner membranes of the mitochondria. Another function of L-carnitine is to remove short-chain and medium-chain fatty acids from the mitochondria in order to maintain coenzyme A levels in these organelles.

Para-Aminobenzoic acid (vitamin Bx, PABA)

Para-aminobenzoic acid or PABA is a non-protein amino acid that is widely distributed in nature. It is sometimes referred to as vitamin Bx, but it is neither a vitamin nor an essential nutrient for humans. PABA is an intermediate in the synthesis of folic acid in bacteria. PABA is usually used along with biotin, pantothenic acid, and folic acid in the restoration of hair, often with vitamin E as well. PABA is also used to reduce aging of the skin and lessen wrinkles. PABA ointment is used commonly to prevent and treat sunburns and, with vitamin E, is often applied to other burns. Para-aminobenzoic acid is important in maintaining healthy skin and hair.

Biotin (vitamin B7)

Biotin is a water-soluble vitamin produced in the body by certain types of intestinal bacteria and obtained from food. Considered part of the B complex group of vitamins, biotin is necessary for the metabolism of carbohydrates, fats, and amino acids (the building blocks of protein). Deficiency, uncommon in humans, may result in hair loss, dry scaly skin, cracking in the corners of the mouth (called cheilitis), swollen and painful tongue that is magenta in color (glossitis), dry eyes, loss of appetite, fatigue, insomnia, and depression.

Vitamin B1 is essential for the body to be able to use carbohydrate as an energy source as well as for metabolising amino acids. lack of sufficient thiamine in the diet can cause loss of appetite, poor digestion, chronic constipation, loss of weight, mental depression, nervous exhaustion, and insomnia. Vitamin B1 deficiency is usually connected to alcoholism, malabsorption diseases, and poor diet.

Vitamin B2 is needed to process amino acids and fats, activate vitamin B6 and folic acid, and help convert carbohydrates into the fuel the body runs on adenosine triphosphate (ATP). A deficiency of vitamin B2 (riboflavin) may result in bloodshot eyes, abnormal sensitivity to light, itching and burning of the eyes, inflammation in the mouth, a sore and burning tongue, and cracks on the lips and in the corners of the mouth.

Vitamin B3 (Niacin) works closely with vitamin B1, vitamin B2, vitamin B6, pantothenic acid, and biotin to break the carbohydrates, fats, and proteins in food down into energy. A niacin deficiency often leads to a chronic illness called pellagra, characterized by gastrointestinal problems, lesions of the skin, and dementia. Vitamin B3 deficiency can occur in alcoholics, individuals with poor or irregular diets, and in individuals with medical conditions causing malabsorption from the intestinal tract.

Vitamin B5 (pantothenic acid) is essential for human growth, reproduction and many normal bodily processes. Many foods contain vitamin B5, therefore a deficiency of this nutrient is rare. Vitamin B5 deficiency causes depression, personality changes, heart problems, increased risk of infections, fatigue, abdominal pains, sleep disturbances, numbness and altered sensation in the arms and legs, muscle weakness, cramps, increased sensitivity to insulin.

Vitamin B6 (pyridoxine) supports more vital bodily functions than any other vitamin. Vitamin B6 deficiency is one of the most common nutritional deficiencies. Vitamin B6 deficiency can cause impaired immunity, skin lesions, and mental confusion. A marginal deficiency sometimes occurs in alcoholics, patients with kidney failure, and women using oral contraceptives. Some of these symptoms can also result from a variety of medical conditions other than vitamin B6 deficiency.

Biotin (vitamin B7) helps in the synthesis of fatty acids, in energy metabolism, and in the synthesis of amino acids and glucose. Biotin deficiency results in fatigue, depression, nausea, muscle pains, hair loss, and anemia. Symptoms of a biotin deficiency include hair loss, a dry, scaly rash around the eyes, nose, mouth, and genital area, decreased appetite, nausea and vomiting and failure to thrive in children.

Folic acid (vitamin B9) is important for any stage of human life which involves growth such as pregnancy, lactation and early growth. Folic acid deficiency causes mood disorders and low levels may play a role in depression, possibly due to a reduction in neurotransmitter levels. Folic acid deficiency during pregnancy increases the risk for neural tube defects including cleft palate, spina bifida, and brain damage.

Vitamin B12 (cyanocobalamin, cobalamin) is considered the most potent vitamin and is one of the last true vitamins that has been classified. Vitamin B12 is essential for normal nervous system function and blood cell production. Vitamin B12 deficiency occurs when there is an abnormally low level of vitamin B12 absorbed in the body. Vitamin B12 deficiency results in impairment of the activities of B12-requiring enzymes.

Sources & further reading