Vitamin D is a hormone, is steroidal in nature, and is synthesized in the skin on exposure to UVB radiations. The UVB radiations enable conversion of precursor, 7-dehydrocholesterol, into cholecalciferol, that is, vitamin D3. Besides endogenous synthesis, exogenously, vitamin D is obtained in two forms, that is, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D, in the body, is metabolized to several metabolites, most active of which is 1, 25-dihydroxycholecalciferol (commonly called as calcitriol) that has a vital role in the regulation of calcium homeostasis and bones mineralisation. 1 Vitamin D and its analogues have an intricate relationship with the skin. They are well known and used for the treatment of topical condition such as psoriasis. They work by regulating keratinolytic differentiation and enforcing immunomodulatory actions. The vitamin is also involved in controlling multiple intracellular pathways which are responsible for the melanin synthesis and melanocyte survival. 2 Maxacalcitol, an active analogue of vitamin D3, is proved to effectively treat comedones, 3,4 and a few studies also report antineoplastic activity 5. Low vitamin D levels in the serum are associated with increased risk of chronic diseases such as hypertension, inflammation, diabetes, and cancer. The hypotheses that local conversion of vitamin D3 into its active metabolite 1, 25-dihydroxycholecalciferol in healthy cells in colon, breast, and prostate can prevent malignancy by inducing cellular maturation, apoptosis, and inhibiting angiogenesis while enhancing the expression of genes that control cellular proliferation is established. 6 Observational studies in humans showed that level of vitamin D3 metabolites is inversely related to coronary artery calcifications. Vitamin D metabolites displayed promising effect in significantly reducing the incidences of angina and myocardial infarction. 7 In another study, it was reported that vitamin D acts as a natural modulator or regulator of immunity. The epidemiologic studies indicate the essential role of vitamin D in the pathogenesis of several systemic and organ-specific diseases such as type 1 diabetes mellitus, rheumatoid arthritis, and
