In autumn and winter, especially in northern latitudes like Germany, sunlight is usually insufficient to produce enough of the body's own vitamin D3. Many people spend more time indoors during the winter, which further reduces sunlight and thus vitamin D synthesis. A deficiency can manifest as fatigue, lack of energy, low mood, or increased susceptibility to infections—typical symptoms of winter fatigue and a weakened immune system.
This seasonal gap presents a clear need—both on the consumer side (self-care in winter) and on the product side (need-based formulations).
Which micronutrients play a role according to studies?
| Nutrient / Mineral | Potential Benefits According to Research / Mechanisms |
|---|---|
| Vitamin D₃ | Supports the immune system: Vitamin D receptors are found on many immune cells; vitamin D influences both the innate and adaptive immune systems. A deficiency is associated with increased susceptibility to infections (e.g., respiratory infections). Mood, energy, and muscle and bone health also suffer from deficiencies—relevant to fatigue and the "winter blues." |
| B vitamins (especially vitamin B12, but also other B vitamins) | play a key role in energy metabolism and the conversion of nutrients into usable energy—relevant against fatigue and exhaustion. Deficiencies (e.g., due to a vegan diet or limited food variety in winter) increase the risk of energy deficiency or exhaustion. |
| Minerals (e.g., magnesium, iron, zinc, and possibly selenium) | Magnesium is essential for many cellular processes—including energy production, nerve and muscle function—and can alleviate fatigue and exhaustion when there is a deficiency. Minerals such as iron, zinc, and selenium are important for the immune system—a deficiency can weaken the immune system. |
Furthermore, there is evidence that when combined—e.g., vitamin D + magnesium + B12—the effects on immune function and stress/energy balance may be synergistic.
Light & Shadow
For vitamin D, there is considerable evidence linking adequate levels to reduced susceptibility to infections, especially respiratory infections—suggesting supplementation during the winter months.
However, the results are not consistent: Some meta-analyses show that vitamin D supplementation does not always reduce the frequency of infections—depending on the population, dosage, and study design.
For B vitamins, magnesium, and other minerals, the data is often more limited: The positive effect on fatigue and energy metabolism is well-documented—particularly in individuals with insufficient levels.
Important: The benefit is usually measurable when a deficiency or suboptimal levels are present—less so when levels are adequate.
There is considerable evidence that vitamin D₃, B vitamins, and minerals play a beneficial role in mitigating winter fatigue and immunological risks—especially during seasons with low light and limited food variety. But blanket, high-dose supplementation is not automatically justified; Actual needs depend heavily on individual nutritional status.
Important Note
Excesses or excessive doses can be risky—especially with fat-soluble vitamins like vitamin D. Supplementation should ideally be based on a blood test or a clearly documented deficiency.
Supplements are not a substitute for a healthy diet, exercise, or sufficient sunlight—a holistic approach remains essential.
Effects can vary significantly depending on age, health status, diet, and lifestyle—therefore, it's not a one-size-fits-all approach.
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Quellen
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8423507/
- https://ods.od.nih.gov/factsheets/ImmuneFunction-HealthProfessional/
- https://www.mdpi.com/2072-6643/12/1/228
- https://vitaminforschung.org/wissenswertes/vitamine-und-immunabwehr
Disclaimer
For legal reasons, we would like to point out that some of the above statements require further research and studies to scientifically prove them. Therefore, not all statements can currently be accepted by conventional medicine.
The information contained in this article regarding legal regulations, approvals, and possible uses of raw materials is based on careful research and our current state of knowledge (as of July 2025). However, we assume no liability for the completeness, accuracy, or timeliness of the information.
The legal framework for food and food supplements is subject to constant change. Therefore, the manufacturer or distributor is always responsible for checking the applicable regulations, EU regulations, and approval lists for the use of raw materials and health-related claims.
In case of legal uncertainty, we recommend consulting legal experts or the relevant authorities.