In a 2021 study, researchers associated a vitamin D supplementation regimen consisting of 0.5 mcg of vitamin D daily for 8 weeks with significant increases in CD4 counts.
Similarly, in a 2022 study, 4 months of vitamin D supplementation boosted CD4 counts in children and adolescents with low CD4 counts and insufficient vitamin D levels.
However, it did not boost CD4 counts in young people with sufficient or deficient vitamin D levels.