B complex: what are the vitamins and what are they for?

Several minerals and vitamins are important to keep our bodies healthy and functioning properly. Each of these nutrients acts in a unique way in the body – influencing from aesthetic issues to the prevention of serious diseases.

In this sense, we can highlight a group of vitamins that is abundant in our body and that has the most diverse actions. We’re talking about complex B !

Understand better what are the vitamins that are part of this group, what are their main functions and where to find them. Check out:


What is the B complex?

The B complex is composed of the following vitamins: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 ​​(pyridoxine), B7 ( biotin ), B9 ( folic acid ) and B12 (cobalamin) .

This set of vitamins is of utmost importance for our organism, considering that each one of them assists several essential functions – such as the production of red blood cells, protection of the immune system, etc.

In general, they can be found in many foods that are easy to find and include in our diet. For example, meats (rich in vitamin B12) or green leaves (rich in vitamin B9).

However, a nutritionist can recommend supplementation of these vitamins with the use of multivitamins when necessary. This can occur due to pre-existing diseases (such as cancer ) or malabsorption of nutrients by the body.

Which vitamins are part of the B complex and what are they for?

We know that there are many vitamins essential for the full functioning of the body. Complex B’s are examples of this.

In general, they act in the metabolism, supply of energy to the body, immune system, health of hair, nails and skin. In addition, for pregnant women they are of paramount importance, considering that they impact on the formation of the fetus (especially vitamin B9).

Check out all the vitamins of this complex and their main functions:

  • B1 (Thiamine) – assists the body in the production of new cells and also acts in the protection of the immune system;
  • B2 (Riboflavin) – has a powerful antioxidant action, which combats the action of free radicals and prevents premature aging and the development of heart disease. It is also essential for the production of red blood cells, responsible for transporting oxygen to the body;
  • B3 (Niacin) – its main function is to increase the levels of HDL cholesterol (popularly called “good cholesterol”);
  • B5 (Pantothenic Acid) – is responsible for breaking down fats and carbohydrates to provide energy, in addition to acting on the production of sex hormones and reducing stress. It also promotes healthy skin, and may even reduce the signs of aging (from topical and / or nutritional use);
  • B6 (Pyridoxine) – together with vitamins B12 and B9, helps to regulate the levels of homocysteine ​​(substance associated with heart disease). It also influences mood and sleep patterns, as it helps the production of serotonin and melatonin (hormones that act on the feeling of well-being and other processes);
  • B7 (Biotin) – it is known as “beauty vitamin”, as it helps to maintain the good appearance of nails, hair and skin. More than that, it participates in the metabolism of proteins, carbohydrates and fat, acts in the production of antibodies and fatty acids;
  • B9 (Folic Acid) – especially important for pregnant women, as it supports the baby’s growth and prevents congenital neurological problems;
  • B12 (Cobalamin) – works with vitamin B9 in the production of red blood cells and helps iron to create the protein that transports oxygen: hemoglobin.

What are the symptoms of a lack of B vitamins?

As we have seen, the B vitamins impact on numerous essential functions of our organism. Therefore, several problems (serious or not) may be due to the deficiency of these nutrients.

Among the most common symptoms of lack of B vitamins, we can mention:

  • Changes in mood;
  • Metabolism problems;
  • Excessive tiredness;
  • Dizziness;
  • Muscle weakness;
  • Loss of hair;
  • Headaches;
  • Anemia;
  • Weak and / or brittle nails;
  • Cramps.
  • Low immunity.

Therefore, if you have one or more of the symptoms mentioned and persist, it is ideal to seek help from a professional. Thus, from exams, it will be possible to obtain the correct diagnosis and know if the problem is (or not) linked to the lack of some vitamin B.

What are the causes of the lack of B vitamins?

In general, when we suffer from a lack of vitamins and minerals in our body, it is a problem related to inappropriate eating habits. That is, it usually occurs due to a diet low in nutrients.

However, in some cases, the person may be suffering due to malabsorption of vitamins by the body – even with a balanced and healthy diet.

This reinforces the need to periodically follow up with a professional, in order to ensure that the levels of nutrients are within the normal range. Thus, if you have a problem, you can have access to the correct diagnosis.

That is, knowing the vitamin deficiency, the doctor may order tests in order to understand the cause of this problem.

It is worth mentioning that some symptoms can serve as a warning for the lack of vitamins in general. Among them, the main ones are excessive fatigue and changes in mood (which can influence discouragement and even depression ).

So, stay tuned (a) to changes in your body and if necessary seek help!

Where to find vitamin B?

Like many vitamins, those of the B complex can be found in a variety of foods. Which makes it even easier to eat, considering that there are many options and we can include some in our routine.

When this is not possible, or even in some nutritional treatments, they can also be ingested through the use of supplements. Remembering that this should only be done with prior guidance.

Read more: Spirulina: what it is for, benefits and harms and how to use

Here are the foods in which you can find each type of vitamin B and some supplement options:


As mentioned, B vitamins are present in many foods. Here are some options you can include in your diet to absorb each type of vitamin B:

  •  B1 (Thiamine) – whole grains, peanuts, beans, spinach, kale, molasses, wheat germ;
  • B2 (Riboflavin) – almonds, rice, milk, yogurt, eggs, Brussels sprouts, spinach, soybeans;
  • B3 (Niacin) – yeast, beef, milk, eggs, beans, green vegetables;
  • B5 (Pantothenic Acid) – avocado, yogurt, eggs, meat, vegetables;
  • B6 (Pyridoxine) – chicken, turkey, tuna, salmon, lentils, sunflower seeds, cheese, rice, carrots;
  • B7 (Biotin) – barley, liver, yeast, pork, chicken, fish, potatoes, cauliflower, egg yolk, nuts;
  • B9 (Folic Acid) – green leaves (especially the darker ones), asparagus, beets, salmon, root vegetables, milk, bulgur wheat, beans;
  • B12 (Cobalamin) – fish, seafood, dairy products, eggs, beef and pork.

These are some examples of foods that have B vitamins. However, if you are deficient in one (or more), a nutritionist may formulate a special diet with the listed foods and others.

In addition, the professional will also be able to indicate the best form of preparation for each food, in order to make the most of all its nutrients.

Read more: Biotin is fattening? What are the side effects?


For people who are unable to maintain a balanced and healthy diet that provides the necessary amounts of vitamins (such as those of the B complex), supplementation may be necessary. This also applies to those who have nutrient absorption dysfunction.

As we have seen, all type B vitamins perform very important functions in our body and that is why it is essential to maintain their adequate levels.

In this sense, when necessary, you should count on the guidance of a professional to choose the correct supplementation for your case. This is important because just as the lack of vitamins is bad, its excess (hypervitaminosis) can also be harmful.

Thus, a nutritionist will know the best according to the conditions of each patient.

Among the supplements that can be prescribed by the doctor in these cases, there are some options such as:

  • B-Vit ;
  • EMS B complex ;
  • Belcomplex B ;
  • B-Suprin ;
  • Compleximed B Tablets or Drops – indicated only for lack of vitamins B1, B2, B3, B5 and B6.

How to take B vitamin supplement?

To find out the best way to take multivitamins according to your case, it is necessary to follow the instructions of the doctor responsible for the treatment.

The administration of vitamins can vary according to your routine and also according to your needs. For example, some people need to take the supplement every day, while others may use it in smaller doses.

However, it is worth mentioning that in many cases it is indicated that the vitamin supplement (orally) is taken at mealtime – mainly lunch or dinner. Thus, there is a better absorption of nutrients by the body.

Check out some useful information regarding the dosage (that is, the indicated dose) and the times to take the vitamins:


As mentioned, it is the doctor (a) who will make the exact indication about the appropriate dose for your case, which will provide a safe and effective treatment.

However, the packaging of the supplements also has information about what is recommended and what is the ideal daily amount.

Therefore, based on the analysis of the deficiencies of the patient’s organism and the indications for the supplement, it will be possible for the professional to define the necessary dose.

It is worth noting that currently, options in the form of jelly candies or gums are also available on the market. These can be an alternative for people who have difficulty taking medications in drops and / or pills, for example.

If you want to opt for this type of treatment, it is also recommended to align with the doctor, considering that there may be divergences in comparison with the more traditional supplements.

See some dosage indications for different B complex supplements:

  • B-Suprin – 1 tablet daily;
  • B-Vit – 25 drops (1 mL), 2 to 3 times a day. Or 1 tablet daily.
  • EMS B Complex – 1 tablet 3 times a day;
  • Vitgold Multivamy Gummies (vitamin B6 and B12 only) – 1 to 3 gums per day.


There is no pre-defined schedule that suits everyone. However, in general, the recommendation is always to take vitamin supplements with meals (preferably lunch or dinner).

This indication is because the body tends to better absorb the nutrients of the supplement when together with food. Therefore, there is a greater guarantee of effectiveness.

The doctor will also be able to make recommendations based on your routine, if necessary.

Can you take it every day?

-Yeah . Almost all vitamin supplements are in daily use, considering that they need to be taken daily for the body to keep the rates balanced. However, this should be done with guidance to ensure safe doses.

We are constantly eliminating substances from the body, including some nutrients. Therefore, this is why we need to constantly replenish vitamins and minerals – which can be done by eating or using supplements.

However, in some cases, the doctor may not recommend daily use. For this reason, it is extremely important to consult and follow professional recommendations, not using any substance indiscriminately (not even multivitamins).

Vitamin B complex: injectable or compressed?

In many of the cases where supplementation is required, it is commonly indicated to do this from oral solutions or tablets. But there are times when it may be necessary to administer the B vitamins injectable – a procedure performed in a hospital setting.

This form of administration can be recommended for patients in the treatment of gastrointestinal disorders, celiac disease, cancer, Crohn’s disease , hypothyroidism , genetic problems, among others. Considering that these factors can negatively influence the absorption of nutrients.

It is also quite common that it is indicated for pregnant women during prenatal care, since vitamin B9 (folic acid) is essential for a good development of the fetus. Therefore, to ensure an even greater effectiveness of supplementation, the obstetrician may indicate that the mother inject the vitamins.

Other people who may also need B vitamins injectable are those who follow vegan or vegetarian diets. This is because they stop eating some (or all) animal foods – the main source of vitamin B12.

It is worth mentioning that injectable administration is recommended, basically, when there are severe cases of vitamin deficiency, due to the guarantee of faster absorption.

This fact is related to the way vitamins enter the body. For example, when we take supplements orally, the B vitamins are metabolized in our intestines, which takes some time.

In the case of injectable administration, the vitamins go directly into the bloodstream, which increases the rate of absorption and nutritional retention.

How long does it take to take effect?

The effect time may vary according to each person, considering that each organism absorbs nutrients at a rate.

But, after a few weeks of using B complex supplementation or changing eating habits (prioritizing foods rich in these vitamins), it is already possible to notice positive changes in the exams.

However, significant results usually appear only after a few months .

As mentioned, we are constantly eliminating substances from the body, including those that are beneficial to health – such as vitamins and minerals.

Therefore, it is not enough to have some care for a short period of time. It is always necessary to prioritize a balanced diet rich in nutrients in order to maintain good health and the body in full working order.

It is worth mentioning that the ideal is to always try to do this from the diet. In other words, supplements are never the first option to keep vitamin levels up to date.

Recalling that there are cases where factors other than diet influence the absorption of nutrients. As, for example, when the person suffers from diseases that damage the intestinal mucosa (cancer, Crohn’s disease, etc.).

In these situations, specific treatment is required and is usually done in a hospital environment.

What is the price and where to buy?

The price * for supplements may vary by brand. In addition, factors such as product availability in your region can also interfere.

But, remember, the ideal is always to buy the prescribed option. In this sense, to help you find the product with the best value, you can choose the platform Consulta Remédios , which compares prices in your locality. And you still get it right at home!

Check the price of some of the B complex supplement options:

  • Complex B EMS – the box with 20 pills varies between R $ 10 and R $ 25;
  • Compleximed B Tablet (indicated only for lack of vitamins B1, B2, B3, B5 and B6) – the box with 100 tablets is around R $ 22;
  • Beneroc – the box with 100 pills varies between R $ 27 and R $ 36;
  • Complex B Medquímica – the flask with 100mL is between R $ 5 and R $ 10.

In addition, some of these vitamins may also be present in the multivitamin formula or in combination with other substances.

As is the case with supplements such as Centrum (R $ 40 to R $ 100 a box of 60 tablets) or Gummies Multivitamin (R $ 88 a package with 100 gums).

* Prices consulted in July 2020. Prices may change.

Vitamin B complex is fattening?

No . The B vitamins do not cause weight gain, considering that they are nutrients that have no calories.

However, what can actually cause a change in the balance is the way of preparing some foods that contain these vitamins – or the amount ingested. This reinforces the need to always try to maintain a healthy and balanced diet, avoiding preparations that involve frying or excess fat.

More than that, it is worth paying attention to the label of supplements. For example, vitamins that are marketed in the form of jelly candies or gums may contain sugar or dyes in their composition.

In such cases, the supplement is causing you to eat calories. But following the recommended usage, you will hardly feel any significant changes in weight.

Complex B supplement: do you have contraindications?

Complex B supplementation is not indicated for people who have already been hypersensitive to any ingredient in the formula. It is also not recommended that use be made by children under 12 years of age , except with medical advice.

Another case of contraindication is related to people who suffer from Parkinson’s (CNS disorder that affects movements) and who are using levodopa alone.

Remembering that to ensure safe use, seek professional guidance!

Can vitamin B complex give side effects?

-Yeah . Although it is not very common for people to experience adverse reactions due to the B vitamins, this can happen.

Side effects do not occur very often due to the fact that they are nutritional substances necessary for the functioning of the body.

However, from supplementation with B vitamins, some people may experience complications such as:

  • Diarrhea;
  • Nausea;
  • Vomiting;
  • Intestinal cramps;
  • Hypersensitivity reactions – which can include symptoms such as inhibition of lactation, itching, facial redness and tingling.

If you experience any of these symptoms during complex B supplementation, it is appropriate to discontinue use and seek immediate medical assistance.