Vitamin D is one of the 24 micronutrients that are crucial for your physical health and vitality. Normally, your body produces the vitamin itself with the help of the sun. However, a deficiency of the sun vitamin can be observed among Germans, especially in the winter months.
In our big vitamin D supplements guide 2021 we want to introduce you to the different vitamin D supplements with their advantages and disadvantages. In addition, you will find all important information on the topic of vitamin D here. This should enable you to find the right preparation for you.
- 1 Weekly newsletter with the best personal finance tips
- 2 The most important facts
- 3 The Best Vitamin D supplements: Our Picks
- 4 Buying criteria: These are the factors you can use to compare and evaluate vitamin D supplements
- 5 Guide: Questions you should ask yourself before buying a vitamin D supplement
- 5.1 What is vitamin D?
- 5.2 How does vitamin D work?
- 5.3 Which works better - vitamin D2 or vitamin D3?
- 5.4 When and for whom is a vitamin D supplement useful?
- 5.5 What is the optimal vitamin D level?
- 5.6 What are the side effects of taking vitamin D?
- 5.7 How do I recognise a vitamin D deficiency?
- 5.8 What vitamin D supplements are available?
- 5.9 How much do vitamin D supplements cost?
- 5.10 What alternatives are there to vitamin D supplements?
- 5.11 What is the best way to take vitamin D?
- 5.12 What foods naturally contain vitamin D?
- 5.13 Should I take vitamin D in combination with other nutrients?
The most important facts
- Vitamin D is mainly known for its bone-strengthening effect. It also plays an important role in calcium and phosphate balance and in other metabolic processes in the body.
- Most vitamin D is produced in the skin with the help of the sun and a small amount is taken in with food. If it is not possible to meet your needs in this way, we recommend taking vitamin D supplements.
- A vitamin D deficiency can impair the normal bodily functions of humans, weaken the immune system and promote diseases.
The Best Vitamin D supplements: Our Picks
Buying criteria: These are the factors you can use to compare and evaluate vitamin D supplements
In the following we would like to show you which factors you can use to compare and evaluate vitamin D supplements. This will help you make your decision. In summary, these are the criteria:
In the following paragraphs, we present what is important in the individual criteria.
The dosage form is the most important distinguishing feature of vitamin D supplements. As already described in detail above, vitamin D is available in the form of tablets, capsules and drops. The different dosage forms all have advantages and disadvantages. The type of vitamin D preparation is often decisive for the price.
The dosage is a decisive factor in buying a vitamin D supplement from many points of view. In general, you should prefer lower-dose vitamin D3 products to higher-dose supplements. This way you can better adjust the dose to your needs.
For example, if you take tablets with a dosage of 10,000 I.U. but only need 5,000 I.U., this is not healthy for your body in the long run.
On the other hand, taking a low-dose vitamin D supplement can also be very tedious. Nobody likes to swallow five tablets or capsules in a row to reach their daily dose of vitamin D. Before buying, calculate how many tablets, capsules or drops you would need to take to reach your daily dose with the product you want. At the same time, you can calculate the cost per dose. This allows you to compare vitamin D supplements in different doses, and you are sure to get the cheapest deal.
Each product has a best-before date (MHD). It tells you how long the effect of the preparation is guaranteed. The shelf life of vitamin D supplements varies depending on the dosage form. Vitamin D drops usually contain little to no additives and have the shortest shelf life.
We recommend that you adjust the package size to the expiry date and your required dose. After the expiry date, there may be an increased risk of side effects. If you have found a product at home that is past its best-before date, you should dispose of it properly for safety reasons.
Ingredients, additives and allergens
Depending on the form of administration, vitamin D supplements contain different ingredients, additives and allergens. Ideally, a vitamin D supplement should be free of additives and allergens such as maize, soy, yeast, peanut, gluten and lactose. For vegetarians and vegans, supplements must also not contain gelatine or other ingredients of animal origin. Additives often serve only technological purposes. They can trigger pseudoallergic reactions. Particularly sensitive persons, allergy sufferers and children should avoid these substances. Additives include:
- Colourings and preservatives
- Thickeners and gelling agents
- Acidulants and flavour enhancers
- Magnesium stearate
Understanding the composition of a vitamin D product is not always easy. Choosing the right product often takes a lot of time, especially for vegetarians, vegans and allergy sufferers. Additives are often only listed as E-numbers. If you are unsure about the ingredients, it is best to contact the manufacturer.
Guide: Questions you should ask yourself before buying a vitamin D supplement
What is vitamin D?
Vitamin D is not a vitamin in the true sense of the word, but a hormone. Unlike other vitamins, vitamin D can be produced in the body with the help of UV-B radiation. In humans, vitamin D is largely produced in the skin under the influence of sunlight and is only absorbed to a small extent through food. Vitamin D is involved in the regulation of important metabolic processes and is responsible for the regulation of entire systems of the human organism.
How does vitamin D work?
Effect on bone health
Vitamin D plays an important role in bone metabolism. The sunshine vitamin ensures that calcium and phosphate are absorbed from the intestine and incorporated into the bones. It thus plays an important role in bone mineralisation. A high vitamin D level leads less often to bone fractures(1). This was found in a study that examined people between the ages of 65 and 85. The risk of bone fracture was reduced by 22 percent in people who received vitamin D supplements.
Effect on muscles
Vitamin D also plays an important role in supplying your muscles. Muscles need vitamin D as a nutrient. A balanced vitamin D level in your body strengthens muscle performance. This is especially true for older people over the age of 60. Taking vitamin D capsules can significantly improve the functions of the lower extremities of the musculoskeletal system and relieve symptoms (2).
Vitamin D deficiency is particularly common among athletes. This leads to reduced muscle function and muscle weakness. Studies provide inconsistent results regarding the effect of vitamin D supplementation on muscle function in athletes.
Some studies see a positive influence of vitamin D supplements on muscle performance, others deny such an effect. A 2019 meta-study concluded that vitamin D supplementation positively affects muscle strength in the lower extremities, but not in the upper extremities (3).
Effect on the immune system
Vitamin D is also important for a functioning immune system. If there is a serious deficiency of the sun vitamin, the body's own defences are weakened. Vitamin D helps produce defence cells and substances and prevents inflammatory immune reactions. In addition, it seems that people with high vitamin D levels get sick less often (4).
Scientists disagree about whether vitamin D can prevent cancer. What is certain is that vitamin D influences the immune system, which is important for the defence against cancer cells (5). In a review from 2014, a research team summarised all the previously published studies on this topic - a total of 18 studies with around 50,000 people (6). The results are sobering. The researchers believe it is possible that low vitamin D levels are not the cause of certain diseases such as cancer, but merely the consequence.
Which works better - vitamin D2 or vitamin D3?
Your body can process both vitamin D2 and D3, but to different degrees.
While vitamin D2 has long been considered equivalent to vitamin D3, recent research suggests that vitamin D3 may be significantly more effective than vitamin D2. Vitamin D3 causes vitamin D levels to rise much faster than vitamin D2 (7).
When and for whom is a vitamin D supplement useful?
In addition to meeting its acute needs, it also stores vitamin D reserves in fat and muscle tissue, which it can fall back on in winter. If you belong to one of the following groups of people, however, you should think about your vitamin D supply:
- Elderly people
- People with dark skin
- Chronically ill people
- Pregnant and breastfeeding women
- Babies and small children
- Night shift workers
Older people often only rarely come into contact with the sun or the skin's ability to produce vitamin D decreases. This can quickly lead to a vitamin D deficiency. People whose skin is more pigmented need more sunlight for their body's vitamin D production than less pigmented people.
Light-skinned people also need to be careful: If you always use sunscreen outside, UVB radiation will not reach your skin. In this way, you largely prevent the production of vitamin D.
Risk groups also include people who suffer from chronic gastrointestinal, liver or kidney diseases or who take medicines that impair vitamin D metabolism (e.g. antiepileptic or cytostatic drugs). Likewise, pregnant and breastfeeding women, infants and small children have an increased vitamin D requirement. Night shift workers or people who do not show much naked skin due to their job or for cultural or religious reasons can also benefit from an additional vitamin D intake.
What is the optimal vitamin D level?
Some studies indicate that a good normal value must be at least 30 ng/ml. Moreover, a higher normal value or a value slightly above the normal range is said to have more positive effects than a value below 30 ng/ml (1, 8, 2).
The goal is therefore to maintain a level above 30 ng/ml in both children and adults in order to reap the full health benefits of vitamin D. The German Nutrition Society (DGE) speaks of a desired vitamin D supply in terms of bone health at a blood concentration of at least 20ng/ml. If the body's own vitamin D formation is lacking, this concentration is achieved with an intake of 20 micrograms of vitamin D per day.
|Vitamin D supply||values in ng/ml||values in nmol/l|
|Vitamin D deficiency||below 20||below 50|
|Vitamin D deficiency||20 to 35||50 to 80|
|Good to high vitamin D levels||35 to 90||80 to 225|
|Vitamin D over-supply||90 to 150||225 to 374|
|Toxic vitamin D level||above 150||above 374|
The concentration of 25-hydroxyvitamin D in blood serum is used as a marker for assessing supply because it reflects vitamin D intake through diet and the body's own vitamin D production. Vitamin D values can be expressed in two different units, ng/ml or nmol/l. 1 ng/ml corresponds to 2.5 nmol/l. At a normal value, there are usually no health consequences to worry about. These only become apparent in the case of an undersupply or, at the latest, a severe vitamin D deficiency below 20 ng/ml.
The only way to find out your vitamin D level is to take a blood test. If you tell your doctor about symptoms that occur with a vitamin D deficiency, he or she will carry out a blood test. However, vitamin D blood tests are usually not necessary. What you get in vitamin D in spring, summer and autumn will usually supply your body in winter as well. Vitamin D is stored in the body for several months.
What are the side effects of taking vitamin D?
Poisoning due to excessive intake of supplements, high-dose medication or high consumption of fortified foods is possible because vitamin D, as a fat-soluble vitamin, can be stored in fat and muscle tissue.
Vitamin D is responsible for the absorption of calcium from food. If vitamin D is overdosed by food supplements over several months, this can lead to so-called hypercalcaemia, an excessive absorption of calcium. This is manifested by fatigue, exhaustion, bone pain, muscle weakness, severe thirst, nausea, vomiting, stomach pain, difficulty walking and confusion. As a result, kidney problems can also occur due to increased calcium absorption.
Your body can benefit from vitamin supplementation in many ways. However, you should not overdo it with the dosage. But there is no need to worry too much, because hypercalcaemia is only observed at a daily vitamin D dosage of about 40,000 IU. Even at very high doses of around 10,000 IU daily, however, no symptoms of hypercalcaemia could be found (9, 10).
How do I recognise a vitamin D deficiency?
- Susceptibility to infections
- poor wound healing
- Decline in performance
- Muscle and joint pain
- Hair loss
- Cardiac arrhythmia
What vitamin D supplements are available?
Each form has its advantages and disadvantages. Whether you choose vitamin D in tablets or capsules or in liquid form as drops depends solely on your preferences and needs. The following is a brief overview of the different forms of vitamin D.
Vitamin D drops
Vitamin D drops can be dosed individually and are easier to swallow than capsules or tablets. They also contain little or no additives. Therefore, drops are the ideal form of administration for babies and small children to cover their vitamin D needs.
With drops, the vitamin is already in an oily solution, which allows your body to absorb and utilise the vitamin D optimally. Studies have shown that liquid vitamin D (dissolved in oil) increases vitamin D levels more quickly than other forms of administration (12, 13).
Since vitamin D drops often do not contain preservatives, they do not have as long a shelf life as capsules or tablets. When buying vitamin D, check the best-before date and choose the best package size for you. In addition to the short shelf life, the higher price is one of the disadvantages of vitamin D drops.
Vitamin D tablets
Tablets are one of the most popular forms of vitamin D. They are usually very cheap. They are usually very inexpensive and have a long shelf life. Tablets are also a very popular form of administration because of their low price.
Additives are added to vitamin D tablets during production. Although these are considered harmless, they reduce the purity of the preparation. In addition, vitamin D tablets should be taken with meals together with some fat in order to be better absorbed by the body. In one study, the increase in vitamin D levels was lowest when taking vitamin D tablets (12).
Vitamin D capsules
Vitamin D3 soft capsules or softgels are rubbery capsules filled with vitamin D3 already dissolved in liquid. This form of preparation contains virtually no additives and is therefore purer than vitamin D tablets. In addition, the vitamin D absorption from capsules is better than from tablets (12).
As a disadvantage, it should be mentioned that the capsule shells are often made of gelatine and are therefore not suitable for vegetarians and vegans. Capsules are also more expensive to produce than tablets. Unlike drops, however, capsules do not contain vitamin D dissolved in oil. An exception are the so-called soft capsules, which are tightly closed capsules containing vitamin D oil or gel.
How much do vitamin D supplements cost?
|Vitamin D tablets||from approx. 5 euros|
|Vitamin D capsules||from approx. 10 euros|
|Vitamin D drops||from approx. 20 euros|
As a rule, you have to pay for vitamin D supplements yourself. Only if there is an actual deficiency and your doctor prescribes the preparation will the health insurance fund cover the costs. The recommendations of the German Nutrition Society (DGE) are often used as a basis for vitamin D deficiencies, which many critics say is far too low.
What alternatives are there to vitamin D supplements?
In order for your skin to make its own vitamin D, you need to avoid using sunscreen. Otherwise, the UVB radiation cannot be absorbed and converted.
The body's own synthesis varies from person to person and depends on latitude and season. Therefore, the DGE recommends that adults should expose themselves to the sun for about five to 25 minutes per day with uncovered face, hands and parts of arms and legs. The intensity of sunlight from March to October is sufficient for a sufficient formation of the vitamin from (11).
Your diet also contributes an estimated ten to 20 percent to your vitamin D supply. Unfortunately, only a few foods contain appreciable amounts of vitamin D. These include fatty sea fish, certain offal, edible mushrooms and eggs. These products are generally consumed in small quantities.
What is the best way to take vitamin D?
What foods naturally contain vitamin D?
It is important to know that a sufficient intake of vitamin D is not possible through diet alone. Nevertheless, we recommend that you always include foods rich in vitamin D in your diet. The following table (according to Souci/Fachmann/Kraut, 2008) gives you an overview of foods and their vitamin D content:
|Food||Vitamin D (micrograms per 100 grams)|
|Herring||7.80 - 25.00|
|Margarine||2.50 - 7.50|
Should I take vitamin D in combination with other nutrients?
You should also take vitamin K because vitamin D strongly promotes calcium resorption. Vitamin K acts as a counterpart and regulates the increased calcium absorption. If your body is not sufficiently supplied with vitamin K2, excess calcium is deposited in the body and dangerous calcification of organs and vessels is possible.
You should also make sure you have a sufficient supply of magnesium. Your body needs this mineral to convert vitamin D into its active form. If there is not enough magnesium in your body, vitamin D supplementation is of no use. The vitamin remains unused because the transport molecules do not work without magnesium.
Caution: Calcium should only be supplemented by people at risk of osteoporosis to reduce the risk of bone fractures. In healthy people, an oversupply can damage the body.
Image source: Dmitrii Ivanov / 123rf
Trivedi Daksha P, Doll Richard, Khaw Kay Tee. Effect of four monthly oral vitamin D3 (cholecalciferol) supplementation on fractures and mortality in men and women living in the community: randomised double blind controlled trial BMJ 2003; 326 :469
Heike A Bischoff-Ferrari, Thomas Dietrich, E John Orav, Frank B Hu, Yuqing Zhang, Elisabeth W Karlson, Bess Dawson-Hughes, Higher 25-hydroxyvitamin D concentrations are associated with better lower-extremity function in both active and inactive persons aged ≥60 y, The American Journal of Clinical Nutrition, Volume 80, Issue 3, November 2004, Pages 752–758, https://doi.org/10.1093/ajcn/80.3.752
Zhang, Lin & Quan, Minghui & Cao, Zhen-Bo. (2019). Effect of Vitamin D supplementation on upper and lower limb muscle strength and muscle power in athletes: A meta-analysis. PLOS ONE. 14. e0215826. 10.1371/journal.pone.0215826.
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Bjelakovic G u.a. (2014). Vitamin D supplementation for prevention of cancer in adults. Cochrane Database Syst Rev CD007469.
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DGE online: Wie viel Sonne braucht der Körper, um über die körpereigene Bildung ausreichend Vitamin D zu produzieren? Wie ist das im Herbst und Winter im Vergleich zum Sommer?
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