Tested 25 Vitamin D3 Stiftung Warentest, supplements in December 2025. Many products were over-dosed or combined with unnecessary additives. Read our clear, easy English guide to the results, what they mean, and what to do next
Introduction — in short
Stiftung Warentest, Germany’s major consumer test organization, published a large Vitamin D test in December 2025. They checked 25 dietary supplements that claim to contain Vitamin D (mostly D3). The headlines were striking: many products were judged unnecessary for most people and several had doses higher than recommended for general daily use. (Stiftung Warentest)
Table of Contents
This article explains the findings in plain English. You will learn:
- What Stiftung Warentest tested and why it matters.
- How many products passed or failed.
- The safety and dosage advice they give.
- Practical steps you can take if you take Vitamin D.
Trusted citations are included so you can read the original test if you want. (Stiftung Warentest)
What did Stiftung Warentest test?
Stiftung Warentest examined 25 vitamin D products sold in Germany. The list included well-known brands, drugstore brands and some pharmacy products. Testers looked at:
- The actual amount of Vitamin D in the product.
- Whether the label dose fits official recommendations.
- If the product contains unnecessary other vitamins or minerals.
- Risks from over-dosing or wrong labeling. (Stiftung Warentest)
Their lab tests measured the real vitamin D content and compared it to what the manufacturer claims. They also evaluated whether the daily dose suggested by the product matched safe limits set by German authorities. (Stiftung Warentest)
Main finding in one sentence
Most tested Vitamin D products are either unnecessary for many people or have doses higher than recommended for general, unsupervised use. Only a few products were recommended outright. (n-tv)
How many products were recommended?
According to the published results:
- Only a small number (around 2 out of 25) were clearly recommended without reservations.
- Several products were described as “suitable with restrictions” because their dose was slightly above the conservative recommendation or because the actual content varied a little from the label.
- Many were judged “less suitable” or “not suitable” due to high doses or unnecessary combinations with other substances. (Stiftung Warentest)
(If you want the exact product list and ratings, check Stiftung Warentest’s test page for the full table.) (Stiftung Warentest)
Why were so many products criticized?
There are three big reasons:
- Overdosing in everyday products.
Stiftung Warentest noted that many supplements offer doses above 800 International Units (I.E.) per day as a standard daily intake. For general preventive use without medical supervision, German advice commonly recommends doses up to 800 I.E./day. Higher doses may be used in special medical situations but should be taken under a doctor’s control. Some products marketed for everyday use provide much higher daily amounts, which can encourage unsupervised overuse. (Stiftung Warentest) - Unnecessary combinations.
Some Vitamin D products include extra vitamins or minerals (for example vitamin A or high amounts of calcium). These combinations are often unnecessary for otherwise healthy people. They can raise the risk of exceeding safe total intake if you also eat fortified foods or take other supplements. (Stiftung Warentest) - Labeling and content variance.
In some cases, the lab measurement did not match the label exactly. Even small variation matters because Vitamin D doses are given in small micro amounts and because safety margins are narrow for long-term high intake. (Stiftung Warentest)
What dose does Stiftung Warentest recommend for everyday use?
Stiftung Warentest cites German expert groups and safety advice that a preventive, unsupervised daily dose for most adults is up to 800 I.E. (20 µg) per day, especially during the sun-poor months (October to March). Doses higher than this should generally be taken only under medical advice and monitoring. (Stiftung Warentest)
Note: Other international bodies (like the EFSA) give different upper limits for safety, but Stiftung Warentest focuses on what German authorities (DGE, BfR) recommend for food supplements and general preventive use. Always compare official local guidance. (DIE WELT)
Safety — what are the risks of too much Vitamin D?
Vitamin D is fat-soluble. That means the body stores it. Too much over a long time can cause high calcium levels in blood. This can lead to:
- Nausea and vomiting.
- Frequent urination and thirst.
- Kidney stones and, in rare severe cases, kidney damage.
- Bone and muscle pain. (n-tv)
Stiftung Warentest warns that long-term, unsupervised use of high-dose supplements can raise these risks. That is why they favor lower daily doses for general consumers. (Stiftung Warentest)
Who actually needs Vitamin D supplements?
According to the test and public health guidance, supplements are useful or recommended for:
- Infants and young children for rickets prevention (follow pediatric guidelines).
- Older adults or people over ~65 who go out less and have lower skin production.
- People with very dark skin living in northern climates.
- People who spend almost no time outdoors (e.g., housebound).
- People with certain medical conditions or medications that affect vitamin D metabolism. (Stiftung Warentest)
For most healthy adults who spend time outside, eat some Vitamin D foods (fatty fish, eggs) and have normal weight, routine supplementation may not be necessary. Testing and medical advice can help decide. (Stiftung Warentest)
Practical advice — what should you do now?
- Don’t panic. If you already take a standard low-dose supplement (≤ 800 I.E./day) and you are not in a risk group, you are probably fine. (Stiftung Warentest)
- Check the label. Look at how many International Units (I.E.) of Vitamin D the product provides per daily dose. If it regularly gives more than 800 I.E. and you have no medical reason, consider switching to a lower dose or talk to your doctor. (Stiftung Warentest)
- Avoid multiple overlapping supplements. If you use multivitamins plus a standalone Vitamin D product, you might be taking more than intended. Add up total Vitamin D intake from all sources. (Stiftung Warentest)
- Talk to your doctor before high doses. If a product claims 1,000 I.E., 2,000 I.E., or offers weekly depot doses, ask a doctor whether that is appropriate and whether a blood test is needed. High doses sometimes have a place in medical treatment but need monitoring. (Stiftung Warentest)
- Test only if needed. Routine testing in healthy people is not always useful. Testing is most helpful for at-risk groups or when a doctor suspects deficiency. (Stiftung Warentest)
How to pick a safer Vitamin D3 product
- Prefer single-ingredient Vitamin D3 products with a clear I.E. per dose.
- Choose a dose that fits the 800 I.E./day conservative rule for general use.
- Avoid products with large amounts of additional minerals or high doses of vitamin A.
- Buy from reputable sellers and check independent test reports (like Stiftung Warentest) for lab results. (Stiftung Warentest)
Quick case: Vigantolvit and others
Stiftung Warentest gave a nuanced rating to some common brands. For example, the Vigantolvit product was judged suitable to prevent deficiency for many users when used at recommended low doses, while other branded supplements with higher daily doses were judged less appropriate for general use. Always check the individual product pages for details. (Stiftung Warentest)
FAQ — short answers
Q: Is Vitamin D3 different from Vitamin D?
A: Vitamin D3 (cholecalciferol) is the natural form made in skin and used in most supplements. It is usually the preferred form for raising blood levels. (Stiftung Warentest)
Q: Can Vitamin D cause kidney damage?
A: Long-term very high intake of Vitamin D can raise blood calcium and harm kidneys. That’s why high doses need medical supervision. (n-tv)
Q: Should I stop my Vitamin D?
A: Don’t stop without thinking. If you are in a risk group or have a doctor’s prescription, continue as advised. If you take a high-dose everyday product without medical reason, discuss switching to a lower dose. (Stiftung Warentest)
Q: Where can I read the full Stiftung Warentest report?
A: The full test and product tables are on Stiftung Warentest’s site (test.de). We cited the report at the top of this article. (Stiftung Warentest)
Short summary — the bottom line
Stiftung Warentest’s December 2025 Vitamin D test sends a clear message: many over-the-counter Vitamin D supplements are set up as if everyone needs high doses — but for most people, that is unnecessary and can be risky. Choose products carefully, favor moderate doses (up to 800 I.E./day) for unsupervised use, and consult a doctor for testing or high-dose therapy. (Stiftung Warentest)
Sources (trusted)
- Stiftung Warentest — Vitamin-D-Präparate im Test (December 2025). (Stiftung Warentest)
- Detailed product page: Vigantolvit Vitamin D3 test result. (Stiftung Warentest)
- News summary: Ärzteblatt / n-TV coverage of the Stiftung Warentest Vitamin D test. (aerzteblatt.de)
Here is a clear, professional medical disclaimer suitable for your Vitamin D3 Stiftung Warentest blog article on Healthytolk.com:
Disclaimer
The information provided in this article is for educational and informational purposes only and is not intended as medical advice. Vitamin D3 requirements vary based on age, health status, lifestyle, and individual medical conditions. Always consult a qualified healthcare professional before starting, stopping, or changing any dietary supplement, especially if you are pregnant, breastfeeding, taking medication, or managing a medical condition. Test results and opinions cited from Stiftung Warentest are based on available data at the time of publication and should not replace personalized medical guidance.