Abstract Hair loss is a prevalent disorder negatively affecting the quality of life and mental health. However, current treatment options are limited, highlighting the urgent need for the development of new therapies. Growing evidence has proven that stem cell-derived nutrient medium and exosome are novel approaches to future hair loss therapy. Limelight (CB-EVs) is an umbilical cord blood-derived exosome product. This study was to investigate the safety and efficacy of Limelight (CB-EVs) for hair growth ex vivo. Our analysis revealed that concentrations of Limelight (CB-EVs) below 5 U/ml demonstrated no cytotoxicity in vitro through MTS assay. In hair follicle culture, concentrations of 0.1, 0.01, and 0.001 U/ml significantly promoted hair elongation while maintaining hair bulb diameter. Analysis of the hair growth cycle indicated a reduced transition from the anagen phase to the catagen phase. Overexpression of Laminin V and Collagen XVII were seen by immunohistochemistry staining. These results endorse the exosome product, Limelight (CB-EVs), offers a safe and effective method for stimulating hair growth ex vivo.