The study design will be a prospective randomized double blind parallel design comparing Vitamin D with Placebo. This study will be conducted in Jordan University Hospital (JUH). The participants will be Healthy males and females with vitamin D deficiency (18 to 49 years old). All eligible males and females who agree to participate in the study will sign an informed witnessed consent form at the beginning of the study. The expected duration of participants participation will be around 120 days and the number of visits for each participant will be 6 visits divided as follows; the first visit will be before 7 days of the initiation of the trial (screening period), the second on day zero of the treatment period, the third on day 30, the fourth on day 60, the fifth on day 90 and the sixth or the last visit will be on day 104 (after 14 days of the last treatment). Therefore the treatment period will be 90 days and the post treatment follow up period will be 14 days.