One hundred ten patients with partial-thickness rotator cuff tears (PTRCTs) were randomized to receive either PRP with normal saline (n=55) or PRP with vitamin C (n=55). The primary outcome was pain reduction, assessed using the Visual Analog Scale (VAS). Secondary outcomes included improvements in the American Shoulder and Elbow Surgeons (ASES) score and the Constant score. Assessments were conducted at baseline, one month, and three months post-injection. Both groups demonstrated significant improvements in pain and functional scores over time. Although group B (PRP + vitamin C) showed slightly greater improvements, the differences were not statistically significant. Overall, the results indicate that PRP injections are effective in reducing pain and improving function within three months, regardless of the addition of vitamin C. These findings support PRP as a non-surgical treatment for PTRCTs, though the incremental benefit of vitamin C remains unclear.