 Subjects with 25OHD level of 20ngml will initially receive a loading dose of 50 000 IU of Vitamin D3 weekly for 8 weeks as is standard clinical practice as recommended by the 2011 Endocrine Society guidelines, and serum 25OHD will be measured again after 8 weeks to ensure that levels are above 20ngml. They will then undergo an 8 weeks washout period in which the subjects will receive 25 000 IU of Vitamin D3 monthly for two months prior to randomization. If subjects are already 20ngml at baseline they will proceed straight to randomisation. 