https://www.selleckchem.com/products/ldc7559.html To assess the effect of platelet-rich plasma as a conservative therapy in individuals with partial-thickness rotator cuff tears or tendinopathy on pain, and function. Embase, MEDLINE, CENTRAL, Web of Science, CINAHL, PEDro, and the grey literature (to 31 March 2021). Randomized controlled trials in English that reported short-term (6 ± 1 months), or long-term (⩾1 year) outcomes (shoulder pain or function) were conducted. Two independent reviewers screened the literature, completed the assessment of the Cochrane's risk of bias and extracted the data. Mean difference or standardized mean difference was used for continuous data. Heterogeneity was identified with test. A total of 11 studies were eligible, and nine studies (  = 629) were included in this meta-analysis, that showed statistically significant short-term effects of platelet-rich plasma on pain relief (MD = -1.56; 95% CI -2.82 to -0.30), Constant-Murley score (MD = 16.48; 95% CI 12.57 to 20.40), and Shoulder Pain and Disability Index (MD = -18.78; 95% CI -36.55 to -1.02). Nonetheless, no long-term effect was observed on pain and function, except Constant-Murley score (MD = 24.30; 95% CI 23.27 to 25.33). The results of minimal important difference reached the minimal clinically important difference, except American Shoulder and Elbow Surgeons. For subgroup analysis, differences of pain relief were statistically significant in platelet-rich plasma-treated groups with double centrifugation, single injection, and post-injection rehabilitation. Our results suggested platelet-rich plasma had positive effects on pain relief and functional improvement for partial-thickness rotator cuff tears and rotator cuff tendinopathy, although the effects may not last for a long time. Our results suggested platelet-rich plasma had positive effects on pain relief and functional improvement for partial-thickness rotator cuff tears and rotator cuff tendinopathy, although the effects