Nikhil Prasad Fact checked by:Thailand Medical News Team Mar 27, 2026 1 hour, 37 minutes ago
Medical News: A new study has found that long-term supplementation with vitamin D3, also known as cholecalciferol, may be associated with a reduced risk of developing Long COVID. Researchers observed that individuals who maintained adequate vitamin D3 levels before infection were less likely to experience persistent symptoms months after recovery. This
Medical News report explores the findings and what they could mean for public health.
Long COVID Continues to Challenge Recovery
Long COVID is a condition where symptoms persist for months after the initial infection has resolved. These symptoms can affect multiple systems in the body, including the brain, lungs, and muscles. Common complaints include fatigue, breathlessness, cognitive difficulties, and ongoing physical discomfort. Understanding why some individuals develop these prolonged symptoms while others recover fully remains a key area of research.
Study Examines Vitamin D3 Specifically
The research focused specifically on vitamin D3 (cholecalciferol), not general vitamin D. Vitamin D3 is the form naturally produced by the body through sunlight exposure and is commonly used in supplements.
The study included 132 adults who had recovered from COVID-19. Among them, 50 individuals had been taking vitamin D3 supplements regularly for at least two years before infection. These individuals were compared with similar patients who were not taking supplements. Long COVID was defined as the presence of at least two symptoms lasting six months after recovery.
The researchers were from the Institute of Endocrine and Metabolic Sciences at Università Vita-Salute San Raffaele and IRCCS Ospedale San Raffaele in Milan, Italy.
Supplementation Linked to Lower Long COVID Rates
Overall, 22.7 percent of participants developed Long COVID. However, the rate was lower among those taking vitamin D3.
Only 14 percent of individuals on long-term vitamin D3 supplementation developed Long COVID, compared to 28 percent of those without supplementation. The association appeared stronger at higher daily doses.
Participants taking at least 1000 IU per day had a lower rate of Long COVID at about 10.5 percent, compared to 27.6 percent in those not taking supplements. In matched comparisons that accounted for age, gender, health conditions, and disease severity, Long COVID occurred in 11.6 percent of those taking vitamin D3 versus 32.6 percent in those without supplementation.
Lower Vitamin D3 Levels May Increase Risk
The researchers also found that individuals who developed Long COVID had lower vitamin D3 levels before infection. This suggests that deficiency may increase susceptibility to prolonged symptoms.
Vitamin D3 levels showed a moderate ability to predict Long COVID risk, indicating that maintaining adequate levels may be important.
Obesity Also Identified as a Risk Factor
The study confirmed that obesity was associated with a higher risk of Long COVID. H
owever, even after adjusting for body weight and other health conditions, vitamin D3 supplementation remained associated with a lower risk.
This suggests that the relationship between vitamin D3 and Long COVID is not solely explained by other underlying factors.
Limitations and the Need for Further Research
Despite the promising findings, the study has limitations. It was observational and conducted in a single center with a relatively small sample size. This means it cannot prove that vitamin D3 directly prevents Long COVID.
Other factors such as lifestyle, diet, and sun exposure may also influence outcomes.
Conclusion
The findings suggest that long-term vitamin D3 supplementation, particularly at doses of 750 to 1000 IU per day or higher, is associated with a lower risk of developing Long COVID. Maintaining adequate vitamin D3 levels before infection may play an important role in recovery outcomes. However, larger studies are needed to confirm these findings and better understand the relationship.
The study findings were published in the peer reviewed Journal of Endocrinological Investigation.
https://link.springer.com/article/10.1007/s40618-026-02858-8
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