This is double blind randomized controlled trial study using 92 subject with diabetes mellitus type 2divided into 2 group, one group as control and other group as vitamin D group. At the end of study the study subject only left 40 subjects in each group. Vitamin D group received vitamin D 5000 IU and the control group received calcium carbonate, microcrystalline cellulose, magnesium stearate, sodium starch glycolate for 6 months. The goal of this study was to determine whether suplmentation Vitamin D 5000 IU for 6 months have any effect on HbA1c, insulin, HOMA-IR nd VCAM-1 in Diabetes mellitus type 2

Both supplementation tablet were made in the same shape, color, odor and packaging. The study was conducted from August 2024 until March 2025. The inclusion criteria in this study were male and females age 18 - 65 years old, had been diagnosed T2DM, duration T2DM ≤ 3 year, HbA1c > 6,5 %, used single antidibetic, were willing to follow the protocol of the study, and were willing to participate in this study after receiving explanations, by signing informed consent. The exclusion criteria were used insulin therapy, had liver disease, renal, disease, pregnant women, or breast feeding women, alergy, hypercalsemia, had been consuming vitamin D in three months before the study. During the study semiquantitative recording of food frequency was carried out at the beginning of the study, after 3 month and 6 months supplementation.

Subjects who passed the initial screening (age, duration of T2DM, taking one type of oral antidiabetic drug) were subjected to laboratory screening consisting of albumin, SGPT, calcium, creatinine. Furthermore subjects who met the inclusion and exclusion criteria were randomized and examined for blood pressure, pulse rate, body weight, height, abdominal circumference followed by drawing venous blood samples. Blood sampling was performed 3 times, namely at the beginning of the study, after 3 months and 6 months supplementation. Subjects were asked to fast 12 hours before venous blood sampling. A 10 ml venous blood was drawn from each subject, made into serum and frozen at minus 20 degree Celcius for use in the simultaneous determination of fasting blood glucose, HbA1c, vitamin 25(OH)D, fasting insulin, HOMA-IR and VCAM-1 concentrations, after the total number of subjects was reached. In addition albumin, SGPT, calcium and creatinine were also examined to monitor adverse event. The determination of vitamin 25(OH)D was performed by method direct competitive chemiluminescent immunoassay (CLIA), determination of insulin was performed by method sandwich enzyme linked immunosorbent assay .(ELISA), while VCAM-1 was determined by enzyme immunoassay

Inclusion Criteria:

• male and females age 18 - 65 years old
• had been diagnosed T2DM,
• duration T2DM ≤ 3 year
• HbA1c > 6,5 %
• used single antidibetic
• were willing to follow the protocol of the study and were willing to participate in this study after receiving explanations, by signing informed consent.

Exclusion Criteria:

• used insulin therapy
• had liver disease, renal disease
• pregnant women, or breast feeding women
• alergy
• hypercalsemia
• had been consuming vitamin D in three months before the study.