Hello dear I understand your concern Yes vitamin D cause hair loss. Please note the Vitamin D status definition: Severe deficiency Deficiency Sufficiency 20 ng/mL Risk of toxicity 50 ng/mL So your are in deficiency state. Vitamin D is immunomodulator. It has hormone action, maintain bone and calcium metabolism. It also prevent diabetes, hypertension, heart disease, various cancer, bone fracture So take treatment to prevent future complication You should take 50,000 IU/week for 8 week. You can also take stoss therapy: 3-6 lakh units over 1-5 days keep the serum levels of 25(OH)D 30 ng/dL which is considered to be the optimal level. Exposure to sunlight for 2 hour / week with open hand , forearm and face, feet between 10 am to 12 noon However, to maintain vitamin D level in the sufficiency range the duration of UVR exposure particularly in relation to time of the day, season or skin pigmentation, remains to be determined. Excessive exposure to sunlight does not lead to vitamin D toxicity. Take following advice: Dietary and supplemental sources of vitamin D: Oily fish such as salmon, mackerel and sardines, cod liver oil, liver and organ meats,fortified milk. Hair loss is due to nutritional deficiency. Take revital multivitamin tablet. Hope this may help you. Contact HCM for further health query Best regards Dr. Sagar