Is vitamin B complex good for increasing energy?

While vitamin B-12 can boost energy, concentration and mood in people suffering from deficiencies of the vitamin, it cannot do so for people who already receive sufficient vitamin B-12, according to Healthline. The average adult only needs 2.4 micrograms of vitamin B-12 daily.

Vitamin B-12 helps convert food into glucose, which the body uses for energy, states Healthline. It also helps in the production of red blood cells, bone marrow and some elements of DNA. People who are most at risk for vitamin B-12 deficiency are AIDs patients, patients with celiac or Crohn's disease, vegans, patients undergoing chemotherapy, and people who take antiseizure medications or prescription antacids.