Last updated: August 12, 2021

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Welcome to ReviewBox Brasil! Today we are going to talk about a vital substance for our health: vitamin D. Although it is synthesised in the body through exposure to the sun and, to a lesser extent, through the ingestion of certain foods, it is not uncommon to need vitamin D supplementation. But, amidst so many options, we will show you in this article what you should check before buying the ideal vitamin D.


  • Essential for bone health, the immune system and for preventing or treating various diseases, vitamin D is vital for human beings.
  • In excess, however, this vitamin can be very harmful to the body.
  • Therefore, we will show you how, when and how much vitamin D you should take and how to choose the best supplement.

The best Vitamin D: Our Picks

Those looking for vitamin D need the right dosage and proven quality. Knowing this, manufacturers are increasingly investing in customised options. Therefore, below we will present to you the best Vitamin D options available on the market today.

Buying Guide

It may seem like a simple task to purchase Vitamin D. However, you need to consider many variables before you even start supplementing this substance. That is why we have created this Buying Guide with all the information you will need to make the best decision when buying Vitamin D.

Mulher tomando comprimido de vitamina.

Vitamin D is vital for the good health of our bodies. (Source: Valerii Honcharuk / 123RF)

What is vitamin D?

Vitamin D was named so because it was the fourth substance discovered, after vitamins A, B and C. But the fact is that it is not a vitamin. It is actually a pro-hormone. In other words, vitamin D is a precursor of hormones which are synthesized by the organism. Even so, it is commonly referred to as a vitamin.

In general terms, vitamin D is necessary for the maintenance of the bone tissue and the immune system.

But the fact is that this vitamin controls 270 genes, including cells of the cardiovascular system. Vitamin D is even used to treat autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. Acquired mainly through exposure to sunlight, the fact is that between 60 and 80 per cent of Brazilians have Vitamin D insufficiency or deficiency. This is because, over the decades, people's habits have changed. Because of the high rates of skin cancer, the population has increased the use of sunscreens, besides staying longer in closed places. But because it is essential for the human body, the absence of vitamin D in the body can cause a series of complications and diseases. Therefore, in many cases, laboratory-produced supplementation is necessary for the prevention and treatment of a series of diseases.

How to obtain vitamin D?

Vitamin D can be absorbed by the body through exposure to the sun, food intake or supplementation. The sun accounts for 80% to 90% of the vitamin D the body receives. Foods of animal origin also have vitamin D, but not in sufficient quantity to benefit the body. Therefore, to avoid lack of the substance, experts recommend that you expose yourself to the sun for a period of 15 to 20 minutes every day. If you have dark or black skin, the time of exposure to the sun should be 45 minutes to 1 hour a day. The curious thing is that the best time to expose yourself to the sun and ensure vitamin D is the same period when doctors recommend more attention to avoid skin cancer.

Mulher deitada na grama tomando sol.

The sun is the best source of vitamin D for your body. (Source: silviarita / Pixabay)

To actually absorb vitamin D, you should sunbathe between 10am and 4.30pm. To ensure protection from the damaging effects of this period, experts warn that you just need to avoid prolonged sun exposure between 12pm and 3pm. You also need to keep your body free of clothes and sunscreen, since the amount of vitamin D that will be absorbed is proportional to the amount of skin that is exposed.

Despite protecting the skin against cancer, the fact is that sunscreen inhibits the retention of vitamin D by up to 95%.

So to suppress your vitamin D needs while protecting your skin from the damaging effects of the sun, you should only use sunscreen for the recommended period of time to get the vitamin. It is also worth noting that even windows hinder the absorption of vitamin D. This is because ultraviolet rays of type B (UVB), which are able to activate the synthesis of vitamin D, cannot pass through glass. In general, exposure to the sun will guarantee good quantities of the substance. But this is not the rule. That's why it is important to be monitored by a doctor to check if supplementation is necessary. It is also worth remembering that vitamin D derived from sunlight is only effective in spring and summer. Therefore, during the rest of the year, especially in winter, vitamin D supplementation is recommended.

Are foods rich in Vitamin D sufficient as supplementation?

As we have seen, the quantity of vitamin D present in food is small. Therefore, food alone is not enough to guarantee vitamin D in the organism. Nevertheless, they can act as supplements. All the food sources of vitamin D are of animal origin, since the vegetable sources cannot synthesize the vitamin. But even the food with the highest amounts of the substance, salmon, contributed only 6.85% of daily vitamin D needs. In addition, foods rich in vitamin D are also very high in saturated fat. That is, when eaten in large quantities can lead to vascular disease. Still, depending on your nutritional need, your doctor may recommend that you supplement sun exposure and supplementation with foods rich in this vitamin. It is therefore important that you know which foods contain the most vitamin D. Check out the table below with the main ones:
Amount of vitamin D (IU) Percent Daily Value of vitamin D
Salmon (100g) 685 6.85%
Tuna (100g) 227 2.27%
Sardines (100g) 193 1.93%
Egg (unit) 43.5 0.43%
Cheddar cheese (50g) 12 0.12%
Beef (100g) 15 0.15%

What can Vitamin D deficiency cause?

Vitamin D deficiency can cause a range of health problems, including 17 types of cancer. A lack of it increases the risk of heart problems, osteoporosis, flu and colds, and autoimmune diseases such as multiple sclerosis and type 1 diabetes. In pregnant women, vitamin D deficiency increases the risk of miscarriage, favours pre-eclampsia and raises the chances of the child being autistic. In addition, lack of vitamin D can cause gestational diabetes, premature birth and infections. The main factor causing the deficiency is lack of sunshine, as people spend large periods of time indoors. To better understand what the lack of this substance generates in our body, see below the main consequences of vitamin D deficiency:

  • Depression: Low levels of vitamin D can be associated with cardiovascular and neurological diseases, including depression.
  • Bone problems: Deficiency of this nutrient can cause rickets in childhood and osteoporosis in adulthood.
  • Heart disease: Those who are deficient in this nutrient are twice as likely to suffer a heart attack.
  • Diabetes: The lack of this substance favours the disease.
  • Loss of muscle strength: The absence of the vitamin leads to loss of strength and increases the risk of falls and fractures.
  • Autoimmune diseases: Vitamin D can contribute to the onset of some diseases and is already being used to treat autoimmune diseases.
  • Cancer: A lack of vitamin D can lead to several types of cancer, including breast cancer, prostate cancer and melanoma.
  • Autism: As vitamin D is important for brain development, it helps prevent autism during pregnancy.
  • Respiratory problems and colds: Children with vitamin D deficiency are more likely to developrespiratory infections. Adults contract more colds.

It is important to emphasize that any type of treatment with vitamin D supplements should only be carried out by doctors. This is because, as we will see below, excess consumption can cause health problems.

Who should use Vitamin D supplements?

Besides natural sources, vitamin D can also be found in the form of supplements. And, in general, people who have vitamin D deficiency and insufficiency are advised by their doctors to take the supplementation. In addition, the supplement can also be used in the treatment of some diseases. To find out whether you should take supplementation, a blood test is required. Recently, the Brazilian Society of Clinical Pathology/Laboratory Medicine (SBPC/ML) announced the change in the Vitamin D reference value. Until then, the value considered normal for the amount of vitamin D detected by the exam was above 30 ng/mL. However, nowadays, values starting from 20 ng/mL are being accepted as normal. Therefore, according to SBPC, patients whose results are between 20 and 30 ng/mL do not need vitamin D replacement. Check below the reference values of vitamin D that can be detected in the blood test:
Reference value Indication
Less than 10 ng/mL Vitamin deficiency
Between 10 and 20 ng/mL Vitamin insufficiency
Greater than 20 ng/mL It is desirable for healthy population
Between 30 and 60 ng/mL It is recommended for risk groups such as elderly, pregnant women, patients with osteomalacia, rickets, osteoporosis, inflammatory and autoimmune diseases

What is the importance of Vitamin D in the elderly?

Older people produce less vitamin D in response to sun exposure because of age-related metabolic issues. The amount of the substance produced in a 70-year-old, for example, is on average a quarter of that synthesised by a 20-year-old. It is therefore important that older people talk to their doctors about the possibility of taking vitamin D supplements. In addition, it is recommended that, when taking supplements, the person should stay hydrated and maintain a balanced diet. This will serve to prevent health problems, especially in the kidneys.

What are the side effects of Vitamin D?

When taken in the recommended amounts, vitamin D has no side effects. However, when taken in excess it can harm the kidneys by causing increased calcium absorption. Therefore, it is important that consumption of more vitamin D than the recommended amount is only done under medical supervision. It is important to note that excess vitamin D can only be taken by supplementation.

Excess vitamin D can cause serious damage to health, especially to the kidneys. The excess only occurs with inadequate use of supplementation.

The sun and food do not cause an excess of vitamin D in the body. This is because, as we have seen, foods do not contain large amounts of the substance, and obtaining it through the sun's rays is regulated by the skin. That is, our skin stops the production of vitamin D when it reaches the necessary values. However, taking too much vitamin D through supplements without medical advice can be very dangerous. There is a risk of an increase in the concentration of calcium in the blood and this can affect the kidneys, which can even lose their function.

What is the recommended dosage of Vitamin D supplementation?

The amount of supplement to be taken varies according to age, the dose of the medicine and the degree of vitamin deficiency in the person. Therefore, it is fundamental to have a medical evaluation and follow-up. Even so, according to several studies carried out recently, the orientation for people over 50 kg is to consume between 1,000 and 4,000 international units (IU) of vitamin D every day. The same goes for pregnant and lactating women. For children, the guideline is to ingest up to 1,000 IU of vitamin D for every 5 kg of weight. In other words, if a child weighs 30 kg, for example, he can take up to 6,000 units of vitamin D per day.

Vitamina D e suco de laranja em mesa próxima à piscina.

To know the daily dose of Vitamin D supplementation you need medical follow-up. (Source: Divulgação Senhora Vitamina / Amazon)

But as these values vary according to the profile of the person and the context of their health condition, overweight people, for example, can take up to 3,000 IU daily. On the other hand, people over the age of 70 may be recommended supplements of up to 3,500 IU per day.

What is the best time to consume the Vitamin D supplement?

It is worth remembering that as it is fat-soluble, vitamin D is best absorbed in the presence of a fat source. A study by the Cleveland Clinic in the United States has shown that taking vitamin D with the main meal of the day can increase the concentration of the vitamin in the blood by up to 50%.

Experts recommend that the best time to take the vitamin D supplement is during lunch. In addition, the meal should contain some type of fat, whether it is of vegetable or animal origin.

What are the advantages and disadvantages of Vitamin D?

As we have seen, the presence of the correct amount of vitamin D in our body is essential for our health. So, the great advantage of vitamin D is that it facilitates the absorption of calcium by the body. And calcium is essential for the healthy development of bones and teeth. With this, the vitamin is able to reduce the risks of fracture and osteoporosis. But besides improving bone health, vitamin D has the advantage of preventing diseases such as obesity and diabetes. Another advantage of this vitamin is that it helps tone muscles, promote greater gains in strength and muscle mass and prevent falls.

Homem fazendo flexão ao ar livre.

Besides the advantage for bones and immune system, Vitamin D strengthens muscles and mass gain. (Source: rawpixel / Pexels)

In addition, Vitamin D prevents high blood pressure and cardiovascular diseases such as heart attacks and strokes. Vitamin D is also a potent inhibitor of cancer cell growth, being able to even reduce metastasis. The only disadvantage of vitamin D is that, if consumed in excess (which can only occur through supplementation), it can cause serious damage to health, especially to the kidneys. Below you will find the main advantages and disadvantages of vitamin D:

  • Increases the absorption of calcium and phosphorus
  • Strengthens bones and teeth, tones muscles and increases muscle mass
  • Improves balance and strengthens the immune system
  • Prevents premature aging and improves cardiovascular health
  • Prevents some types of cancer, such as colon, rectal and breast cancer
  • Prevents diseases such as obesity, diabetes, hypertension and multiple sclerosis
  • In excess, through supplementation, it is harmful to health

How much does it cost?

The price of Vitamin D varies a lot depending on the manufacturer, the dosage, the quantity and the components of the formula. But, in general, you will find Vitamin D costing between £15 and £350. Of course, you don't need to buy the most expensive one. In general, it is possible to get a quality vitamin for an affordable price, depending on your usage needs.

Where to buy it?

You will find Vitamin D for sale in pharmacies, supplement shops, department stores and hypermarkets such as Lojas Americanas and Extra. Even so, we suggest you make your purchase at online shops such as Amazon Brasil. By doing so, you not only guarantee more brand and price options, but you also get Vitamin D from the comfort of your own home.

Purchase criteria: Factors to consider before buying Vitamin D

As we have seen, the first step you should take before including vitamin D supplementation in your routine is to get your blood tested and have it monitored by your doctor. After that, you need to understand what differentiates one product from another among the many vitamin D options available in the market today. For this reason, we have selected the main factors that should be taken into account before buying vitamin D:

Below, we will explain each of these factors in detail for you to make the best decision and invest in the vitamin D that will actually meet your needs.


The first factor you should take into account before buying Vitamin D is the type of the substance used as an active ingredient. There are several types of vitamin D, but the two most important forms are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is of animal origin. It is synthesised in the skin from cholesterol after exposure to a reasonable amount of sunlight. Vitamin D2, on the other hand, is of plant origin and is only available from food. The fact is that vitamin D3 is much more effective than vitamin D2 when it comes to increasing blood levels of this vitamin in the body. In addition, vitamin D3 is stored in adipose tissue much more effectively than vitamin D2.

Pote com cápsulas de vitamina.

The most common active ingredient found in supplements is Vitamin D3. (Source: mel_gama/ Pixabay)

You can find vitamin D supplements made with both the active ingredient of D3 and D2. The latter is generally more relevant for those with dietary restrictions, such as vegetarians and vegans. Still, the most common is that you will find D3, since this type is considered more complete and effective. Below, you can see the main differences between vitamin D3 and vitamin D2:

Vitamin D3 Vitamin D2
Active ingredient Colecalciferol Ergocalciferol
Origin Animal Plant
Efficiency Higher Lower
Storage Higher Lower
Recommendation People without dietary restriction Vegans and vegetarians


Supplements are available in liquid or capsule form.

Another factor that is important for you to check is the form in which vitamin D is presented. Vitamin D supplements are generally available in liquid or capsule form. The fact is that the right choice of this factor may or may not make it easier to take and absorb the vitamin. In general, children and the elderly benefit much more from the drop form because it is easier to digest. But it is also possible to find vitamin D injections, although more rarely. This form is used in cases where a person needs to replace the deficiency quickly.


Next, we recommend that you take into account the concentration of vitamin D in each dose of the supplement. This value (measured in IU, international unit) varies enormously depending on the brand manufacturer. Ideally, together with your doctor, you should define the recommended daily dose you need to consume. On the market, you can opt for products containing between 200 IU and 500 IU of vitamin D in each capsule. But if you opt for the liquid version of the supplement, this concentration is usually 200 IU of vitamin D in each drop.

Frasco de Vitamina D líquida.

Vitamin D concentration varies between brands and format, whether in capsules or drops. (Source: Olha Kozachenko / 123RF)


It is also essential that you take into consideration the quantity of capsules or the total in millilitres of Vitamin D in each bottle. This choice will mainly reflect on the practicality of use and the final price of the product. But this will also depend on your doctor's prescription. To give you an idea, you can opt for Vitamin D packs that contain between 30 and 300 tablets. For vitamin D in liquid form, you can choose from bottles containing between 20 ml and 150 ml. (Source of the highlighted image: puhhha /123RF)