Beyond energy boosts: a clinical review of the vitamin B complex and associated supplementation

Abstract

The vitamin B complex is a group of water-soluble vitamins composed of eight B vitamins: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate/folic acid (B9) and cobalamin (B12). Vitamins are crucial for optimal physiological functions, and thus adequate amounts of vitamins need to be supplied through the diet since they are not synthesised endogenously by the human body. Vitamin B deficiency may occur for a variety of reasons, and depending on the specific vitamin and its functions, symptoms may vary. Due to potential deficiencies, vitamin B supplements are considered to mitigate these effects. Available vitamin B supplementation ranges from Schedule 0 (over-the-counter) to Schedule 4 (scheduled preparations), in various formulations and routes of administration, however, specific dosages need to be considered to prevent toxicity. Vitamin B supplements are not only used for direct supplementation but also to support the function of pharmacotherapy or mitigate adverse drug reactions. This review provides a broad overview of the vitamin B complex, particularly its deficiencies, indications for supplementation, available supplements and potential drug-vitamin interactions.