B-Complex Vitamins

The B vitamins are a group of essential vitamins. B-Complex Vitamins is used for Meeting nutritional requirements, Folic acid in pregnancy and Conditions of deficiency.

Also called: Biovea (United States) · Bplex (New Zealand) · Benerv (Philippines)

Pronunciation: Not established by these sources..

Generic name: b-complex vitamins
Drug class: Dietary supplement (B vitamin combination); not a drug class as such
Form: Not established by these sources for a combined B-complex product.
Route: Oral (by mouth) — stated general context only; the supplied sources do not describe an administration route for a combination product.
Legal status: Dietary supplement. Dietary supplements are not approved by the US FDA for safety or effectiveness before sale. Specific legal status by country is not established by these sources.

Availability and supply rules vary by country

Trade names by country: United States · New Zealand

Australia: · Full directory

What b-complex vitamins is and how it works

The B vitamins are a group of essential vitamins. MedlinePlus lists the B vitamins as: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B7 (biotin), and folic acid. NCCIH lists the B vitamins as thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), cobalamin (B12), biotin, and folate/folic acid. These vitamins help the process your body uses to get or make energy from the food you eat, and they also help form red blood cells. Not getting enough of certain B vitamins can cause diseases; a lack of B12 or B6 can cause anemia. These sources do not establish a definition or content for a combined 'B-complex' supplement product. (1) (2) (3) (4)

Most people can meet their nutritional needs from food, and the Dietary Guidelines for Americans 2020–2025 recommends that people should aim to meet their nutritional requirements through a healthy eating pattern that includes nutrient-dense foods. Health care providers may recommend supplements for people with certain medical conditions, and some people who do not get enough vitamins and minerals from food alone (including people on low-calorie diets or who avoid certain foods, such as strict vegetarians or vegans) may want to consider taking a vitamin and mineral supplement. If you consume fortified foods and beverages along with dietary supplements, you should make sure that your total intake of vitamins and minerals is not more than the safe upper limits for any nutrients. The science on supplements is often weak, mixed or insufficient, and this page reports no claim beyond the quoted sources.

Mechanism of action: how b-complex vitamins works

The supplied sources do not provide pharmacology for a combined B-complex product. NHS describes the functions of individual B vitamins: thiamin helps break down and release energy from food and keeps the nervous system healthy; riboflavin helps keep skin, eyes and the nervous system healthy and helps release energy from food; niacin helps release energy from food and keeps the nervous system and skin healthy; pantothenic acid helps the body release energy from food; vitamin B6 helps the body use and store energy from protein and carbohydrates and form haemoglobin; biotin is needed to help the body make fatty acids; folate helps form healthy red blood cells and reduce the risk of neural tube defects; vitamin B12 helps make red blood cells and keep the nervous system healthy, release energy from food and use folate. MedlinePlus states that B vitamins help the process the body uses to get or make energy from food and help form red blood cells. (1) (2) (4)

What is B-complex vitamins used for?

Meeting nutritional requirements

The sources state that most people can meet all of their nutritional needs from food. NCCIH notes that some people who do not get enough vitamins and minerals from food alone — including people on low-calorie diets or who avoid certain foods, such as strict vegetarians or vegans — may want to consider taking a vitamin and mineral supplement, and that health care providers may recommend supplements for people with certain medical conditions. Health care providers will recommend a supplement if needed — for example, vitamin B12 if you have difficulty absorbing vitamin B12 from food (including many people over 50 and those with pernicious anemia or digestive disorders) or if you follow a vegan or vegetarian diet that does not include adequate levels of vitamin B12. These sources do not establish that a combined B-complex supplement treats, prevents or cures any condition. (2) (3)

Functions of individual B vitamins (as stated by NHS)

NHS describes the functions of individual B vitamins: thiamin (B1) helps the body break down and release energy from food and keeps the nervous system healthy; riboflavin (B2) helps keep skin, eyes and the nervous system healthy and helps the body release energy from food; niacin (B3) helps the body release energy from food and keeps the nervous system and skin healthy; pantothenic acid helps the body to release energy from food; vitamin B6 helps the body to use and store energy from protein and carbohydrates in food, and helps the body form haemoglobin; biotin is needed in very small amounts to help the body make fatty acids; folate helps the body form healthy red blood cells and reduce the risk of birth defects called neural tube defects in unborn babies; vitamin B12 helps make red blood cells and keep the nervous system healthy, release energy from food, and use folate. These are functions of individual nutrients, not established benefits of a combined B-complex product. (4)

Folic acid in pregnancy

Conditions of deficiency

Not getting enough of certain B vitamins can cause diseases; a lack of B12 or B6 can cause anemia. NHS states that a lack of folate could lead to folate deficiency anaemia and that a lack of vitamin B12 could lead to vitamin B12 deficiency anaemia. These sources do not establish that B-complex supplements treat these conditions. (1) (4)

Before taking b-complex vitamins

Do not take / not appropriate for

The supplied sources do not list contraindications for a combined B-complex supplement. NHS guidance on individual B vitamins includes being advised not to take more than 10mg of vitamin B6 a day in supplements unless advised to by a doctor, and not taking too much of the other B vitamins as this might be harmful. (all products) (4)

Tell your clinician about

Whether you eat fortified foods or beverages (such as cereals or drinks with added vitamins and minerals) in addition to supplements, so that your total intake of vitamins and minerals is not more than the safe upper limits for any nutrients.
Whether you take a blood thinner, such as warfarin (Coumadin and other brand names) — NCCIH states to talk to your health care provider before taking any multivitamin/multimineral or other dietary supplement that contains vitamin K.
If you are pregnant, trying for a baby or could get pregnant, to discuss folic acid advice, including whether a higher dose is advised, and to speak to your doctor first for higher-dose folic acid.
If you are pregnant, note the NHS advice to avoid liver (given in the sources as a source of thiamin, pantothenic acid and folate).
Whether you are over 50, have pernicious anemia or a digestive disorder, or follow a vegan or vegetarian diet, in relation to vitamin B12.
Whether you are a smoker or former smoker, in relation to products providing large amounts of vitamin A (from NCCIH safety guidance on MVMs, not specific to B vitamins).

(2) (3) (4)

B-complex vitamins dosage and how to take it

The supplied sources do not describe how to take a combined B-complex supplement, nor any dose, schedule or duration.
NHS states that you should be able to get all the thiamin, riboflavin, niacin, pantothenic acid, vitamin B6, biotin, folate and vitamin B12 you need from your daily diet, and that if you take supplements you should not take too much as this might be harmful.
NHS states that thiamin, riboflavin, niacin and pantothenic acid cannot be stored in the body, so you need them in your diet every day, and that there are no long-term folate stores, so you need to eat folate-containing foods frequently.
Do not change your supplement dose, product or schedule based on this page; speak to a clinician, pharmacist or prescriber.
Do not use this page to decide to stop or continue any prescribed treatment; that decision belongs to your clinician.

(4)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4)

Missed dose

The sources used do not provide missed-dose instructions for B-complex vitamins. Contact your health care provider or pharmacist for guidance; do not take an extra dose on your own.

Overdose

The supplied sources do not give overdose amounts or management for B-complex supplements. NHS advises not to take too much of the individual B vitamins as this might be harmful, and gives upper limits above which effects are unclear or harm is possible: thiamin 100mg or less a day unlikely to cause harm; riboflavin 40mg or less a day unlikely to cause harm; niacin 17mg or less a day of nicotinic acid or 500mg or less a day of nicotinamide unlikely to cause harm; pantothenic acid 200mg or less a day unlikely to cause harm; vitamin B6 — do not take more than 10mg a day unless advised to by a doctor; biotin 0.9mg or less a day unlikely to cause harm; folic acid 1mg or less a day unlikely to cause harm; vitamin B12 2mg or less a day unlikely to cause harm. If you think you have taken too much, seek advice from a clinician or poison-information service. This page is not a source of overdose guidance. (4)

B-complex vitamins side effects

The supplied sources give limited information on effects of high intakes of individual B vitamins. NHS states that for thiamin, riboflavin, pantothenic acid, biotin and vitamin B12 there is not enough evidence to know what the effects might be of taking high daily doses of supplements. Effects described for other B vitamins are given below.

Effects of high niacin intake

What to notice: Taking high doses of nicotinic acid supplements can cause skin flushes. Taking high doses for a long time could lead to liver damage. There is not enough evidence to know what the effects might be of taking high daily doses of nicotinamide supplements.

What to do: Do not take too much niacin. Speak to a clinician if you have taken high doses. (4)

Effects of high vitamin B6 intake

What to notice: Taking 200mg or more a day of vitamin B6 can lead to a loss of feeling in the arms and legs known as peripheral neuropathy. This will usually improve once you stop taking the supplements, but in a few cases when people have taken large amounts of vitamin B6, particularly for more than a few months, the effect can be permanent. The effect of taking vitamin B6 at doses between 10mg and 200mg is unclear.

What to do: NHS advises: do not take more than 10mg of vitamin B6 a day in supplements unless advised to by a doctor. Do not stop or continue supplements on your own; ask the clinician you see to advise. (4)

Masking of vitamin B12 deficiency by high folic acid intake

What to notice: Taking doses of folic acid higher than 1mg can mask the symptoms of vitamin B12 deficiency, which can eventually damage the nervous system if it is not spotted and treated. This is particularly a concern for older people because it becomes more difficult to absorb vitamin B12 as you get older.

What to do: Do not take too much folic acid; discuss dose with a clinician, particularly if you are older. (4)

General principle for high or multiple supplement use

What to notice: NCCIH states that taking a daily dose of a basic multivitamin/multimineral is unlikely to pose a health risk for healthy people, but taking them at high doses or taking many different supplements may cause adverse side effects.

What to do: Discuss persistent or troublesome symptoms, and any high-dose or multiple supplement use, with a clinician or pharmacist. (2)

Suspected effects of high-dose supplements

What to notice: Loss of feeling in the arms and legs (peripheral neuropathy) possibly related to vitamin B6, skin flushes or possible liver effects related to nicotinic acid, or any symptom you suspect is caused by supplement use.

What to do: Contact a clinician promptly for assessment; let the clinician advise on whether to continue or change the supplement. This page does not provide treatment or dosing instructions. (4)

Serious warnings

Not established for a combined B-complex product — not_established

Symptoms: The supplied sources do not establish emergency warnings specific to a combined B-complex supplement.

Action: For any severe or worrying symptom, seek medical attention promptly and let the clinician you see decide on any treatment change. This page does not provide emergency or treatment instructions. (2) (4)

Vitamin B6-related peripheral neuropathy (high-dose supplement use) — serious

Symptoms: Loss of feeling in the arms and legs, which can become permanent in a few cases when large amounts of vitamin B6 have been taken, particularly for more than a few months.

Action: NHS advises not to take more than 10mg of vitamin B6 a day in supplements unless advised to by a doctor. If you have such symptoms, seek medical assessment promptly and let the clinician advise on the supplement. (4)

Folic acid masking vitamin B12 deficiency — serious

Symptoms: Taking doses of folic acid higher than 1mg can mask the symptoms of vitamin B12 deficiency, which can eventually damage the nervous system if not spotted and treated; this is particularly a concern for older people.

Action: Do not take too much folic acid; seek clinical advice, especially if you are older or have concerns about vitamin B12. (4)

Safety context for supplements in general (NCCIH) — caution

Symptoms: If you consume fortified foods and beverages along with dietary supplements, your total intake of vitamins and minerals could exceed safe upper limits for some nutrients. NCCIH states that taking high doses or taking many different supplements may cause adverse side effects.

Action: Discuss total intake with a clinician or pharmacist. Safe upper limits information is available from the NIH Office of Dietary Supplements Dietary Supplement Fact Sheets as cited by NCCIH. (2)

Interactions

Medicine or test	Effect	Action
Blood thinners (e.g. warfarin, Coumadin and other brand names)	NCCIH states that multivitamins/multiminerals providing nutrients at or up to 100 percent of the Daily Value do not typically interact with medications, but advises that if you take a blood thinner such as warfarin, you should talk to your health care provider before taking any MVM or other dietary supplement that contains vitamin K.	Talk to your health care provider before taking any supplement containing vitamin K. This guidance is about MVM/supplements generally, not a combined B-complex product. (2)
Fortified foods and beverages (e.g. cereals, drinks with added vitamins and minerals)	If you consume fortified foods and beverages along with dietary supplements, your total intake of vitamins and minerals may exceed the safe upper limits for any nutrients.	Check total intake against safe upper limits and discuss with a clinician or pharmacist. (2)
Other supplements and medications	There is no standard or regulatory definition for what nutrients any dietary supplement must contain or at what levels, and manufacturers choose the ingredients and amounts. Taking many different supplements may cause adverse side effects. The supplied sources do not provide specific interaction data for a combined B-complex product.	Give the clinician and pharmacist a complete list of supplements and medicines you take. (2)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy and women who could get pregnant

NHS advises that if you are pregnant, trying for a baby, or could get pregnant, it is recommended that you take a 400 microgram folic acid supplement daily until you are 12 weeks pregnant, starting before you get pregnant, to help prevent neural tube defects such as spina bifida. Some women at increased risk are advised to take a higher dose of 5mg of folic acid each day until 12 weeks pregnant and should speak to their doctor first. NCCIH states that taking excess amounts of vitamin A (preformed retinol form, not beta-carotene) during pregnancy has been shown to increase the risk of birth defects, and that the Dietary Guidelines for Americans 2020–2025 provides recommendations for specific populations, including women who are or may become pregnant. NHS lists liver among sources of thiamin, pantothenic acid and folate with the note: avoid liver if you are pregnant. (2) (4)

Women who breastfeed and people aged 60 and over

NCCIH notes that the Dietary Guidelines for Americans 2020–2025 provides recommendations for specific populations, including women who breastfeed and people ages 60 and over. It also notes that the risk of obtaining insufficient iron from the diet applies to women of childbearing age, pregnant women, infants, young children and teenage girls. NHS states that it becomes more difficult to absorb vitamin B12 as you get older, and that masking of vitamin B12 deficiency by higher-dose folic acid is particularly a concern for older people. (2) (4)

Vegans and vegetarians

NCCIH states that people who avoid certain foods, such as strict vegetarians or vegans, may want to consider taking a vitamin and mineral supplement, and that a health care provider will recommend a supplement such as vitamin B12 if you follow a vegan or vegetarian diet that does not include adequate levels of vitamin B12. NHS states that as vitamin B12 is not found naturally in foods such as fruit, vegetables and grains, vegans may not get enough of it. (2) (3) (4)

People with difficulty absorbing vitamin B12 and certain medical conditions

NCCIH states that health care providers will recommend a supplement if needed — for example, vitamin B12 if you have difficulty absorbing vitamin B12 from food (including many people over 50 and those with pernicious anemia or digestive disorders). NCCIH also notes that health care providers may recommend supplements for people with certain medical conditions. (3) (2)

Smokers and former smokers

NCCIH advises that smokers, and possibly former smokers, should avoid multivitamin/multimineral products that provide large amounts of vitamin A (as preformed retinol or beta-carotene or some combination of the two), as a few studies have linked high supplemental doses of these nutrients with an increased risk of lung cancer in smokers. This is general supplement guidance and not specific to B vitamins. (2)

Young children

NCCIH states that iron supplements are a leading cause of poisoning in young children, so they should be kept out of children's reach. The supplied sources do not provide B-complex-specific guidance for children. (2)

Monitoring

Before starting

The supplied sources do not define a monitoring protocol for a combined B-complex supplement.
NCCIH advises checking that total intake of vitamins and minerals from fortified foods and beverages plus dietary supplements is not more than the safe upper limits for any nutrients, using the NIH Office of Dietary Supplements Dietary Supplement Fact Sheets for safe upper limit information.
Review the product label, including the Supplement Facts panel and the list of all ingredients (ingredients not in the Supplement Facts panel must be listed under 'Other Ingredients'), because there is no standard or regulatory definition for what nutrients a supplement must contain or at what levels.
Discuss with a health care provider whether a supplement is appropriate for your situation, including any medical condition, pregnancy or breastfeeding, and all medicines and other supplements you take.

During treatment

Report any suspected adverse effects to a clinician or pharmacist; NHS advises not to take too much of any B vitamin supplement as this might be harmful.
If taking vitamin B6, note the NHS advice not to take more than 10mg a day in supplements unless advised to by a doctor.
If taking folic acid, note that doses higher than 1mg can mask vitamin B12 deficiency, particularly in older people.
The supplied sources do not provide laboratory monitoring, dose-adjustment or stopping criteria for a combined B-complex supplement.

(2) (4)

Storage

The sources used do not provide storage instructions for B-complex vitamins. Keep supplements out of children's reach, as the sources state that iron supplements are a leading cause of poisoning in young children. Follow the storage directions on the product label.

Professional information

Information context only. Use the current local supplement regulations, the exact product label, and, where relevant, the individual nutrient guidance. This page does not provide dosing, prescribing or treatment guidance.

All regions

Indication: Any B-complex supplement use

Dose summary: No dose is displayed. The supplied sources do not establish a dose for a combined B-complex product. NHS gives UK reference intakes for individual B vitamins in adults (aged 19 to 64): thiamin 1mg a day for men and 0.8mg a day for women; riboflavin about 1.3mg a day for men and 1.1mg a day for women; niacin about 16.5mg a day for men and 13.2mg a day for women; vitamin B6 about 1.4mg a day for men and 1.2mg a day for women; folate 200 micrograms a day for adults; vitamin B12 about 1.5 micrograms a day; and no amount has been set in the UK for pantothenic acid. These are dietary reference intakes for individual nutrients, not a recommended supplement dose for a combined product. NHS states that you should be able to get all the B vitamins you need from your daily diet.

Renal context: The supplied sources provide no renal or hepatic impairment dosing information. Do not infer a web-based adjustment; discuss with a clinician. (4)

Mechanism of action

Hepatic guidance

The supplied sources provide no hepatic impairment guidance for B-complex supplements. NHS notes that taking high doses of nicotinic acid for a long time could lead to liver damage. Discuss with a clinician.

Overdose note

The supplied sources give no overdose management for B-complex supplements. See the tolerable upper-limit statements in the overdose section, which are per individual nutrient in supplement form. Seek advice from a clinician or poison-information service if you suspect excessive intake. (1) (2) (4)

Frequently asked questions

Do I need a B-complex supplement?

The sources state that most people can meet all of their nutritional needs from food. NCCIH notes that some people who do not get enough vitamins and minerals from food alone (including people on low-calorie diets or who avoid certain foods, such as strict vegetarians or vegans) may want to consider taking a vitamin and mineral supplement, and that health care providers may recommend supplements for people with certain medical conditions. Discuss your situation with a clinician. (2) (3)

How much of each B vitamin does a B-complex supplement contain?

Not established by these sources. NCCIH states there is no standard or regulatory definition for what nutrients any dietary supplement must contain or at what levels, and manufacturers choose which vitamins, minerals and other ingredients, and the amounts, to include. Check the product's Supplement Facts panel and label. (2)

What are the upper limits for B vitamin supplements?

NHS gives the following UK advice for supplement forms: thiamin 100mg or less a day is unlikely to cause harm; riboflavin 40mg or less a day unlikely to cause harm; niacin 17mg or less a day of nicotinic acid, or 500mg or less a day of nicotinamide, unlikely to cause harm; pantothenic acid 200mg or less a day unlikely to cause harm; vitamin B6 — do not take more than 10mg a day unless advised to by a doctor; biotin 0.9mg or less a day unlikely to cause harm; folic acid 1mg or less a day unlikely to cause harm; vitamin B12 2mg or less a day unlikely to cause harm. For thiamin, riboflavin, pantothenic acid, biotin and vitamin B12 there is not enough evidence to know the effects of high daily doses. These are per-nutrient statements, not a combined-product dose. (4)

Can high-dose folic acid cause problems?

NHS states that taking doses of folic acid higher than 1mg can mask the symptoms of vitamin B12 deficiency, which can eventually damage the nervous system if it is not spotted and treated, and that this is particularly a concern for older people. (4)

Do B vitamins help prevent or treat COVID-19?

NCCIH states there is not enough scientific evidence to clearly show that taking any dietary supplement helps to prevent or cure COVID-19. The supplied sources make no B-vitamin-specific COVID-19 claim. (2)

What does the science say about multivitamin/multimineral supplements, which are similar products?

NCCIH states that MVMs cannot take the place of eating a variety of foods that are important to a healthy diet; that taking a daily dose of a basic MVM is unlikely to pose a health risk for healthy people, but taking them at high doses or taking many different supplements may cause adverse side effects; and that most studies have shown little or no effect of MVMs on the risk of health problems, with study interpretation difficult because products vary and because people with healthier lifestyles are more likely to take MVMs. This is MVM evidence, not B-complex-specific evidence. (2)

Are B-complex supplements approved for safety and effectiveness?

Dietary supplements are not approved by the US FDA for safety or effectiveness before sale. (1)

What is the mechanism of action of b-complex vitamins?

What is the generic name of B-Complex Vitamins?

The generic name is b-complex vitamins. (1) (2) (4)

What class of drug is b-complex vitamins?

B-Complex Vitamins is classed as: Dietary supplement (B vitamin combination); not a drug class as such. (1) (2) (4)

References

B VitaminsMedlinePlus, U.S. National Library of Medicine · United States · accessed 2026-10-13 · source 1
Vitamins and MineralsNIH National Center for Complementary and Integrative Health · United States · dated 2023-07 · accessed 2026-10-13 · source 2
Bodybuilding and Performance Enhancement SupplementsNIH National Center for Complementary and Integrative Health · United States · dated 2021-01 · accessed 2026-10-13 · source 3
Vitamin BNHS (UK), Vitamins and minerals · United Kingdom · dated 2020-08-03 · accessed 2026-10-14 · source 4

Brand names by country

Single-ingredient b-complex vitamins names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

The Vitamin ShoppeThe Vitamin Shopperegulator source
Vitamin WorldVitamin Worldregulator source
BIOVEABIOVEAregulator source
Nutrition NowNutrition Nowregulator source
MNP Michael's Naturopathic ProgramsMNP Michael's Naturopathic Programsregulator source
up&upup&upregulator source
Higher NatureHigher Natureregulator source
Kirkland SignatureKirkland Signatureregulator source
MyTritionMyTritionregulator source
Superior SourceSuperior Sourceregulator source

New Zealand

Bplexreference source

View brands in additional countries.

Philippines

Benerv, Neurobase, Neuro