Background: Chromium dinicocysteinate (CDNC) is a unique chromium complex consisting of chromium, niacin, and L-cysteine. Previous preclinical and clinical studies support the safety and efficacy of CDNC in modulating oxidative stress, vascular inflammation, and glycemia in type 2 diabetes. Objective: Herein, we report the results of several exploratory analyses conducted on type 2 diabetic subjects who previously participated in a 3-month randomized, double-blind, placebo-controlled trial and were treated with only metformin as standard diabetic care in addition to receiving the test supplementations. Design: Results from 43 metformin users, who were randomly assigned to receive either placebo (P, n=13), chromium picolinate (CP, 400 µg elemental Cr3+/day, n=12), or CDNC (400 µg elemental Cr3+/day, n=18), were analyzed for blood markers of vascular inflammation, insulin resistance, and oxidative stress at baseline and at 3 months of supplementation. Results: A statistically significant decrease in insulin resistance in the CDNC-supplemented cohort compared to placebo (p=0.01) was observed at 3 months. The CDNC group also demonstrated a significant reduction in insulin levels (p=0.03), protein carbonyl (p=0.02), and in TNF-α (p=0.03) compared to the placebo group. The CP group only showed a significant reduction in protein carbonyl levels (p=0.03) versus placebo. Conclusions: When controlling for diabetes medication, CDNC supplementation showed beneficial effects on blood markers of vascular inflammation, insulin resistance, and oxidative stress compared to placebo. The findings suggest that CDNC supplementation has potential as an adjunct therapy for individuals with type 2 diabetes.