This is a randomized, double-blind, multicenter, 6-month follow-up trial of low (400 IU/day) versus high (4000 IU/day) dose vitamin D supplementation in individuals with pre- and early stage 1 hypertension and vitamin D deficiency. A total of 530 participants (265 participants per treatment arm) will be randomized between 3 sites. Approximately 2,250 participants will be screened between the 3 sites. Vital signs, 24-hour ambulatory blood pressure monitoring, clinical laboratory safety tests and adverse event assessments will be performed to evaluate the effectiveness of the two doses of vitamin D on blood pressure. Blood samples will be stored for future biomarker assessments. The total duration of the study is anticipated to be 18 months, assuming a 12 month enrollment period.

Inclusion Criteria:

• Males or females 18 to 50 years of age
• Systolic blood pressure of 120 to 159 mmHg and Diastolic blood pressure ≤99 mmHg
• Vitamin D deficiency, defined as 25-hydroxyvitamin D <25 ng/ml
• No use of any anti-hypertensive medication in last 3 months or anticipated or planned use in next 6 months
• No use of vitamin D supplementation in last 3 months, defined as vitamin D found in a multivitamin or supplement totaling >400 IU per day or anticipated or planned use in next 6 months

Exclusion Criteria:

• Use of any anti-hypertensive medication in last 3 months or anticipated or planned use in next 6 months
• Use of vitamin D supplementation in last 3 months, defined as vitamin D found in a multivitamin or supplement totaling >400 IU per day or anticipated or planned use in next 6 months
• Use of St. John's wart, rifampin, any treatment for HIV, orlistat, oral glucocorticoids, phenobarbital, phenytoin, mineral oil, or bile acid sequestrants in the last 3 months or anticipated or planned use in next 6 months
• Female who is pregnant, nursing, or of childbearing potential and planning or anticipating pregnancy in next 6 months
• History of diabetes mellitus (including Type 1, Type 2 and diet controlled)
• Serum creatinine >2.0 mg/dl or estimated Glomerular Filtration Rate (GFR) <30 ml/min
• Calcium >10.0 mg/dl or phosphorus >5 mg/dl
• History of kidney stones
• Body mass index >38 kg/m2
• Known cardiovascular disease: defined as prior myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass or stroke
• History of cirrhosis or severe liver disease (defined as history of GI bleeding from liver disease, jaundice or ascites)
• Current heavy alcohol use: defined as drinking 5 or more drinks per occasion on 5 or more days in the past 30 days
• History of ulcerative colitis, Crohn's disease, celiac disease, colostomy, pancreatic enzyme deficiency, short bowel syndrome, gastric bypass, cystic fibrosis, or dumping syndrome.
• Allergy to coconut
• Regular use or planned use of artificial tanning lights in next 6 months
• Use of any investigational product or device in last 3 months or planned use in next 6 months
• Any condition which could limit the ability to complete and comply with 6-month follow up
• Unwillingness or inability to comply with study requirements
• Inability to provide informed consent