Vitamin D is sometimes used to support or treat backache, particularly when there is a suspicion of deficiency. Scientific evidence suggests that vitamin D deficiency is associated with musculoskeletal pain, including chronic back pain. Several observational studies have found a correlation between low serum 25(OH)D levels and the prevalence of back pain, especially in older adults and certain populations at risk for deficiency. Some small intervention studies and randomized controlled trials have shown that vitamin D supplementation may reduce pain scores or improve function in individuals with low baseline vitamin D levels and non-specific musculoskeletal pain, which can include backache.

However, the overall strength of the evidence is moderate at best. Large meta-analyses and systematic reviews often report conflicting results: while supplementation may benefit those with clear deficiency, it does not appear to significantly reduce back pain in the general population or in those with normal vitamin D status. There is also no robust evidence that vitamin D supplementation is effective for specific causes of back pain, such as herniated discs or spinal stenosis. Therefore, scientific support exists primarily for individuals with documented deficiency, rather than as a general remedy for backache.

In summary, the link between vitamin D and backache is supported by some scientific evidence, especially in deficient individuals, but the benefit for the wider population is unclear. Supplementation should be considered when deficiency is confirmed or highly suspected.