How to Take Vitamin D: 2021 Recommendations

how to take vitamin d

Until recently, the norms of how to take vitamin D in Europe were very different from those established, for example, in the United States. Previously, the maximum allowed dosage for the registration of food additives and for food products in Europe was considered to be a dosage of 600 international units (IU, IU), which in the United States, for example, passes along the lower limit.

how to take vitamin d2

The previously recommended intake of vitamin D3 (200 IU) in the CEE region was almost 2 times lower than the norm for infants!

Thus, the release of some vitamin D3 capsules at a dosage of 600 IU balanced exactly on the verge between the European maximum and the minimum American consumption.

This dosage still remains as reasonable as possible for daily consumption from food sources (which include supplements).

But in the case of the slightest deficiency, or even for people over 70 years old, this dosage will be insufficient, and you may need to drink many capsules, which is not always convenient.

What is Vitamin D?

Vitamin D

Vitamins D are fat-soluble vitamins that play an important role in calcium absorption and bone health, as well as immune function.

Our skin produces vitamin D when exposed to sunlight, but due to the risk of skin cancer, many people avoid sun exposure or use sunscreen that prevents the body from producing vitamin D.

Many types of milk and dairy products, as well as orange juice, are also fortified vitamin D. However, many of us do not get enough vitamin D and need supplements.

There are two forms of vitamin D supplementation:

  1. vitamin D2 (ergocalciferol);
  2. vitamin D3 (cholecalciferol).

It is important to understand the differences when choosing a vitamin D supplement.

What is the difference between vitamin D, D2, and D3?

The term “vitamin D” is a misnomer because you will not find anything labeled simply “vitamin D” in the vitamin rows of pharmacies. Rather, you will choose vitamin D2 (what is vitamin D2?) Or vitamin D3 (what is vitamin D3?). Usually, when vitamin D is mentioned, it is implied that it is vitamin D2. In this article, when vitamin D is mentioned, it will refer to vitamin D2. The names can be confusing because often, patients go to the pharmacy looking for vitamin D and are surprised that there are D2 and D3 there.

Vitamin D2 comes from plant sources like wild mushrooms and fortified foods like milk or grains. Its strength is usually measured in international units, which are abbreviated as “ME” on the label. 50,000 IU capsules are available by prescription only, while lower doses are available over the counter. Vitamin D is less expensive to produce, which is why it is most commonly found in fortified foods.

Vitamin D3 comes primarily from animal sources such as fish oil, oily fish, liver, and egg yolks. When your skin is exposed to sunlight, it produces vitamin D3. For this reason, it is sometimes called the sunshine vitamin. Its strength is also measured in international units. All forms of vitamin D3 are available over the counter.

Consumption Rates

Average consumption in different countries is 2.5-11.2 μg / day (100-448 IU). The established level of need in different countries is 0-11 μg / day (0-440 IU). The permissible upper level of consumption is 50 μg / day. (2000 IU)

The physiological requirement for children is 10 mcg/day. (400 IU)

The specified physiological requirement for adults is 10 mcg/day. (400 IU), for people over 60 years old – 15 mcg/day. (600 IU)

The new recommended dosage has already doubled (from 200 to 400 IU), and the maximum allowed dosage has increased by more than 3 (from 600 to 2000 IU).

How to Take Vitamin D

There are Western formulas on the market with a high concentration of vitamin D3 per capsule. The decision to purchase such formulas is often made under the influence of purely quantitative indicators. But bigger is not always better! Vitamin D3 is fat-soluble and accumulates in the body. Therefore, long-term consumption of high dosages exceeds the established European ones, as well as many established international norms.

In connection with the update of the regulations, we are releasing both the version with the maximum allowed high content of vitamin D3 in Europe (2000 IU) and the version with the previously maximum established and now recommended, for example, for the elderly, dosage: 600 IU. This dosage will be enough for adequate nutritional intake of vitamin D outside of its deficiency or hypovitaminosis, and one can of 400 capsules will be enough for more than a year.

If you suspect you have vitamin D deficiency, we recommend taking analysis and consulting your doctor to determine the required dosage. If this dosage is high, it is more convenient and profitable to take it with the version with a higher vitamin D3 content of 50 mcg (2000 IU).

Importance of Vitamin D

Vitamin D capsule

The main functions of vitamin D are associated with maintaining the homeostasis of calcium and phosphorus, the implementation of bone mineralization processes.

Lack of vitamin D leads to impaired metabolism of calcium and phosphorus in bones, increased demineralization of bone tissue, which leads to an increased risk of osteoporosis.

How Vitamin D3 Deficiency Affects Women

Vitamin D3 affects the quality of sex life. Women with low blood levels of vitamin D3 tend to have worse sex life than women with good levels of vitamin D3. Endocrinologists at Sisli Etfal Teaching and Research Hospital in Turkey report this in the journal International Urology and Nephrology. The researchers asked 108 women between the ages of 22 and 51 to complete a Female Sexual Function Index questionnaire. Sexologists use this questionnaire to determine the quality of women’s sexual functioning, measuring it in points.

Women who score more than 26.55 points usually have a good quality of sex life, and those with lower scores are more likely to have certain problems.

In parallel, the scientists measured the concentration of vitamin D3 in the blood of the women interviewed.

High and Low Blood Levels of Vitamin D: Research Results

Women who scored high on the Female Sexual Function Index and therefore did not have sexual problems had higher blood levels of vitamin D than women with lower scores.

how much vitamin d should i take

The Female Sexual Function Index questionnaire contains questions about “desire, arousal, hydration, orgasm, satisfaction, and genital pain” that women have experienced during lovemaking over the past four years. Women with high vitamin D levels performed better on all factors than women with low vitamin D. In addition, hormone concentrations were measured, including estradiol, testosterone, LH, FSH, DHEA, thyroxine, and TSH in the blood of women. And here, there was no difference in hormone levels between women with a high score and those who had a low score on the index of female sexual function.

Thus, it is unlikely that vitamin D affects sexual functioning through hormonal status since it was not associated with vitamin D. What the mechanism of the association found, the researchers were unable to determine.

Scientists’ Conclusions on the Effect of Vitamin D Deficiency in Women on Sex Life

This study showed that levels of vitamin D3 deficiency are lower in women with sexual dysfunction, as noted in the Female Sexual Function Index Questionnaire,” the researchers write. “However, further studies with a large sample size are needed to understand the pathophysiology of female sexual dysfunction caused by vitamin D3 deficiency.

High Vitamin D Levels Allow Covid-19 Virus to Be Nearly Symptomatic

There are categories of people who can hardly tolerate infection with the covid-19 virus, but the infection has little effect on their health after the illness. Most often, of the symptoms of Covid, they only notice a dry cough. This can be due to the high level of vitamin D or the artificial UV radiation from the tanning bed, which promotes the synthesis of vitamin D in the body. This is evidenced by a study that Martina Kralj, a dermatologist at the Karlovac General Hospital in Croatia, will soon publish in clinical reports.


How the Immune System With High Levels of Vitamin D in the Body Copes With Covid-19

The protagonist of Dr. Kralj’s publication is a 66-year-old man who suffers from a dry cough while being examined by doctors. He has a mild fever but no other symptoms. However, since the case is taking place in the era of the coronavirus, doctors decide to examine this patient properly. He has all the parameters of a person who usually ends up in intensive care due to infection with the Covid-19 virus.

He is not only over 65 years old but also obese, smoked a lot in the past, and quit smoking 6 years ago. He has type 2 diabetes, has high blood pressure, and is on medication for both diseases.

The man also has a joint disease, for which he takes powerful medications that undermine his immune system. And in the course of the examination, to top it off, it turns out that he probably has a kidney defect. Doctors decided to test this man for covid-19. The first PCR test, which should show the presence of coronavirus or viruses similar to it, is positive. After a few weeks, the second test is negative. In the blood of the man, the researchers found antibodies to the dangerous virus. So, the person was infected with the coronavirus, but his immune system has already coped with it.

It was great, but why didn’t he get into intensive care? A possible explanation is that the man had relatively high levels of vitamin D. His blood contained 92.2 nanomoles of 25-OH vitamin D3 per liter (at a rate of 75 nmol / L). This patient was exposed to UV radiation in a tanning bed for several months before the discovery of the fact of infection with covid-19, which was part of the fight against skin disease.


When a covid-19 infection has serious consequences, this situation is usually the result of a virus knocking out T-reg immune cells.

T-reg cells stop immune responses after neutralizing the pathogen, preventing unnecessary tissue damage by the immune system. Vitamin D increases the activity and production of T-reg cells.

Possible Role of Vitamin D on the Course and Outcome of Covid-19: Conclusion

In conclusion, we point to the likely possible role of vitamin D as a positive modifier in the course and outcome of COVID-19, and suggest that routine 25-OH-vitamin D3 status determination may be considered a useful tool for, at least roughly, assessing the outcome of COVID-19. 19, as well as for deciding whether to supplement vitamin D3,” writes Kralj.


  1. Vitamin D3 deficiency is associated with female sexual dysfunction in premenopausal women.Masum Canat, Lütfi Canat, Feyza Yener Öztürk. Int Urol Nephrol. 2016 Nov;48(11):1789-95.
  2. Vitamin D and COVID‐19 in an immunocompromised patient with multiple comorbidities—A Case Report. Martina Kralj Hrvoje Jakovac. Clin Case Rep. 2021;00:1-7.

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