B-complex

Also known as b complex, vitamin b complex, b-vitamin complex.

Last reviewed October 9, 2026 · Jump to references

What is B-complex?

In plain words

B-complex is a mix of B vitamins that help the body use food for energy, make blood cells, and keep nerves working. The body absorbs these vitamins and uses them to support many everyday chemical processes. Researchers study them for vitamin deficiencies and their effects on nerve health and blood function. More is not always better: high amounts of some B vitamins can cause harm, including nerve damage from vitamin B6.

Technical definition

B-complex is a blend of water-soluble B vitamins, typically including thiamine, riboflavin, niacin, pantothenic acid, vitamin B6, biotin, folate, and vitamin B12, with composition varying by product. These vitamins act as coenzymes or coenzyme precursors across multiple enzyme systems rather than at a single receptor, supporting energy metabolism, DNA synthesis, red blood cell formation, and nervous system function. In the United States, B-complex products are generally marketed as dietary supplements and are not FDA-approved to treat disease.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.