"Vitamin B" is really eight different vitamins that share a family name and a lot of teamwork. Here's a clear, one-page guide to what each one does, how much you need, and where it comes from.
Written by Vita Globe Editorial Team | Reviewed against Institute of Medicine Dietary Reference Intakes, NIH guidance and peer-reviewed research
What are the 8 B vitamins and what do they do?
The eight B vitamins are thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), B6, biotin (B7), folate (B9) and B12. Most act as coenzymes that help turn food into energy; folate and B12 are also essential for making DNA and healthy red blood cells, and several support the nervous system[2][3].
Caveat: Each B vitamin has its own recommended amount; the figures below are for adults aged 19–50 and differ in pregnancy, breastfeeding and older age[1].
Sources: IOM DRIs 1998 · Kennedy 2016 · Tardy et al. 2020 · Verified 2026-09-27
In this article
What are the 8 B vitamins, at a glance?
All eight are water-soluble, and they are grouped together because they work so closely with one another in metabolism[2]. Here's the quick reference. Amounts are the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) for adults 19–50[1].
| Vitamin | Main job | Adult daily amount (men / women) |
|---|---|---|
| B1 – Thiamin | Carbohydrate metabolism, nerve function | 1.2 mg / 1.1 mg |
| B2 – Riboflavin | Energy production; helps activate other B vitamins | 1.3 mg / 1.1 mg |
| B3 – Niacin | Forms NAD/NADP, used in hundreds of reactions | 16 mg NE / 14 mg NE |
| B5 – Pantothenic acid | Makes coenzyme A for energy and fat metabolism | 5 mg (AI) |
| B6 – Pyridoxine | Protein metabolism, neurotransmitters | 1.3 mg |
| B7 – Biotin | Fat, carbohydrate and protein metabolism | 30 mcg (AI) |
| B9 – Folate | DNA synthesis, cell division | 400 mcg DFE |
| B12 – Cobalamin | Red blood cells, nerves, DNA synthesis | 2.4 mcg |
Wondering about the gaps in the numbering? Several compounds once labeled B vitamins (such as "B4" and "B8") were later found not to be essential vitamins and were dropped from the list. Inositol, sometimes marketed as "vitamin B8," is one example: the body can make it, so it isn't classed as a vitamin.
Which B vitamins power energy metabolism?
Five of the eight are best known as the "energy team":
- Thiamin (B1) helps enzymes break down glucose, the body's main fuel[2].
- Riboflavin (B2) forms FAD and FMN, coenzymes used in energy production and in converting other B vitamins, such as B6 and folate, into their active forms[2].
- Niacin (B3) becomes NAD and NADP, which carry energy through countless metabolic reactions. Its nicotinic acid form can cause flushing at higher doses[6].
- Pantothenic acid (B5) is needed to make coenzyme A, central to burning fat and carbohydrate[2].
- Biotin (B7) helps enzymes that build fatty acids and make glucose. Deficiency is rare[7].
None of these is a stimulant. They're the machinery, not the fuel. A 2020 review found that supplementing them helps fatigue mainly when status is inadequate[3].
Which B vitamins matter most for blood, nerves and the brain?
Three B vitamins work especially closely together in the "one-carbon" (methylation) cycle, which the brain, nerves and blood cells depend on[2]:
- Vitamin B6 is needed to make neurotransmitters such as serotonin and dopamine, and for protein metabolism[2].
- Folate (B9) is essential for making DNA and for cell division, which is why it's so important before and during early pregnancy[4]. Read more in folate vs. folic acid: what's the difference?
- Vitamin B12 works with folate to make DNA and healthy red blood cells, and keeps nerves working properly. It's found naturally only in animal foods[5].
Because folate and B12 are so intertwined, high folic acid intake can mask the anemia of B12 deficiency while nerve damage progresses[4][5]. That's one reason some people prefer a formula that includes both. For more on B12 forms, see methylcobalamin vs. cyanocobalamin.
Where do you get each B vitamin from food?
| Vitamin | Good food sources |
|---|---|
| Thiamin | Whole and enriched grains, pork, legumes |
| Riboflavin | Dairy, eggs, lean meats, fortified cereals |
| Niacin | Poultry, fish, meat, peanuts, fortified grains |
| Pantothenic acid | Found widely: meat, eggs, mushrooms, avocado, whole grains |
| Vitamin B6 | Poultry, fish, potatoes, chickpeas, bananas |
| Biotin | Eggs, meat, fish, seeds, nuts |
| Folate | Leafy greens, beans, lentils, fortified grains |
| Vitamin B12 | Meat, fish, eggs, dairy, fortified plant foods |
A varied diet covers most people's needs. Vegans are the big exception for B12, which must come from fortified foods or supplements[5].
Do you need all eight in a supplement?
Not necessarily. "B complex" isn't a standardized term, so products differ in which B vitamins they include and how much of each. Some people need one nutrient specifically (for example B12 for a vegan, or folic acid before pregnancy), while others prefer broad coverage. We compare the two approaches in Is B-Complex actually "better" than a single B vitamin?
Whatever you choose, read the Supplement Facts panel. It tells you exactly which B vitamins are in a product and how much of each.
The honest summary
- There are eight B vitamins, each with its own job and recommended amount[1].
- Most help turn food into energy; folate and B12 are vital for DNA and red blood cells[2].
- A varied diet covers most needs; B12 is the main gap for vegans[5].
- Check labels: "B complex" formulas vary.
Our option
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One gummy a day with six B vitamins, including niacin, B6, folate and B12, plus vitamin C and inositol. It's vegan, gluten-free and non-GMO, and tested by an independent third-party lab. See what's actually inside and check the product page's Supplement Facts for exact amounts.
Frequently asked questions
Which B vitamin is the most important?
None is more important than the others; you need all eight. B12 and folate get the most attention because shortfalls are more common in certain groups and have serious effects.
What is vitamin B complex made of?
A B complex combines several B vitamins in one product. Which ones, and how much of each, varies by brand, so check the label.
Are there really only 8 B vitamins?
Yes. The numbering skips because some compounds once called B vitamins were later reclassified. Inositol, sometimes called "B8," isn't officially a vitamin.
Can you take too much of the B vitamins?
Some have upper limits for adults, including niacin (35 mg), B6 (100 mg) and folic acid (1,000 mcg from supplements and fortified foods)[1]. Others, like B12, have no established upper limit[5].
Is biotin a B vitamin?
Yes, biotin is vitamin B7. For hair and skin claims, see our Biotin 101 guide; evidence in healthy people is limited[7].
Sources
- Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academies Press; 1998. doi:10.17226/6015
- Kennedy DO. B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review. Nutrients. 2016;8(2):68. doi:10.3390/nu8020068
- Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A. Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence. Nutrients. 2020;12(1):228. doi:10.3390/nu12010228
- National Institutes of Health, Office of Dietary Supplements. Folate: Fact Sheet for Health Professionals. ods.od.nih.gov
- National Institutes of Health, Office of Dietary Supplements. Vitamin B12: Fact Sheet for Health Professionals. Updated July 2, 2025. ods.od.nih.gov
- National Institutes of Health, Office of Dietary Supplements. Niacin: Fact Sheet for Health Professionals. Updated November 18, 2022. ods.od.nih.gov
- National Institutes of Health, Office of Dietary Supplements. Biotin: Fact Sheet for Health Professionals. Updated January 10, 2022. ods.od.nih.gov
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking medication, or caring for a child.
