According to a study published in 'Gynecological Endocrinology', the Vitamin-D replacement therapy significantly leads to decline in symptoms.

This observational study was performed to investigate the Vitamin-D level in patients with primary dysmenorrhea and estimate the effect of Vitamin-D replacement on symptoms. A total of 100 patients aged 18–30 years followed-up with primary dysmenorrhea diagnosis were involved in this study. Pain severity was estimated using visual analog scale. The 25-hydroxy vitamin D(25(OH)D) levels of the patients were noted, and as per the measurement results, the replacement therapy was used. After that, a follow-up of 3 months was done. At the end of these 3 months, the 25(OH)D level was measured, and the VAS score was examined again after the therapy. 

It was found that 25(OH)D level was insufficient in 23.0%, deficient in 45.0%, and severely deficient in 32.0% of the patients. The VAS score was found to be inversely proportional to 25(OH)D level.

There was a significant reduction in VAS scores after Vitamin-D treatment in all the three groups. The amount of decrease in VAS score was higher in the patients with severely deficient levels of 25(OH)D as compared to the patients with deficient or insufficient levels. In this study, a significant and negative correlation was established between Vitamin-D and symptoms concerning dysmenorrhea.