Vitamin D in winter deserves attention, but not automatically a high dose. To assess your status, distinguish the season, actual blood results and additional intake. A dark month alone does not establish how much a particular person needs.
Why German winter sunshine is insufficient
According to the German Nutrition Society, or DGE, sunlight in Germany from October to March is insufficient to ensure adequate vitamin D production. At the same time, the body's stores contribute to winter provision. Little current sunshine is therefore not equivalent to an already established deficiency. [1]
For an initial personal review, record how much time you usually spend outdoors and whether your circumstances have changed. An extended period spent mainly indoors is different from a single rainy weekend.
20 micrograms are not a universal loading regimen
In the absence of production by the body, the DGE gives an estimated intake of 20 micrograms daily from age one; this equals 800 international units. The figure refers to total intake under that condition, not an additional deficiency treatment suitable for everyone. [2]
| Information | What to record | What it does not establish |
|---|---|---|
| Everyday routine | Time outdoors and longer-term limitations | An exact dose calculated from hours |
| Existing products | Vitamin D per daily serving of every supplement | That different product names prevent overlapping intake |
| Blood testing | Date, result, unit and reason for testing | A dose based solely on someone else's laboratory report |
| Treatment | Prescribed amount and agreed monitoring | That an online plan may replace the prescription |
When blood testing or advice is useful
The DGE recommends assessing vitamin D status when deficiency is reasonably suspected or risk factors are present rather than through general screening. Very limited outdoor time and older age can alter the situation. Blood 25-hydroxyvitamin D is generally used for assessment. [1]
Bring existing results and supplements to a consultation. Ask specifically why supplementation is indicated, how long it is intended to continue and whether monitoring is needed. Tiredness alone is not enough to attribute symptoms to vitamin D.
Avoid overlapping intake
Our calculation example: a multivitamin containing 10 micrograms and a single-ingredient supplement containing 20 micrograms together provide an additional 30 micrograms. This illustrates addition, not a recommended dose. Weekly preparations also belong in the overview and must not accidentally be used daily.
Do not independently change a medically prescribed treatment. Tanning beds are not a recommended solution for vitamin D provision either. [1] A sensible winter plan requires neither a tanning goal nor as many combined products as possible.
Frequently asked questions
Does everyone automatically become vitamin D deficient in winter?
No. The season does not replace individual assessment.
Are 800 international units a high-dose treatment?
Here, this number is the conversion of the DGE estimated intake, not a personal treatment plan.
Should everyone have a preventive blood test?
The DGE recommends testing for reasonable suspicion or risk factors, not indiscriminately for everyone.
Should I combine several vitamin D products?
First record their existing amounts and establish whether additional intake is needed.
Further reading
Check multivitamins for overlapping intake and read product information correctly.
Sources
- German Nutrition Society: Vitamin D questions and answers
- German Nutrition Society: Vitamin D reference values
Editorially updated: September 28, 2026. Calculation example, not a personal prescription. Natur Total also operates a supplement shop.
