To develop a drug to treat hair loss, we evaluated the effects of Laminaria japonica extract mixed with growth factor. After topical application of the L. japonica growth factor mixture to a six-week-old C57BL/6 mouse model, analysis of hair re-growth was determined using a high-resolution hair analysis system, as well as, photographic and histologic analysis. Depilated areas were completely covered with fully-grown hair in all study groups (control group, L. japonica extract group, and L. japonica extract mixed with growth factor group) and the hair re-growth score was the highest in the group treated with L. japonica supplemented with insulin-like growth factor-1 (IGF-1). The width and length of the hair follicles showed a significant increase in the groups treated with L. japonica mixed with IGF-1, compared to the control groups. Groups treated with L. japonica mixed with growth factor showed significantly increased gene expression of IGF-1 and decreased expression of transforming growth factor (TGF)-β, compared to the control groups. We confirmed that IGF-1 was more effective in promoting hair growth than vascular endothelial growth factor (VEGF). Therefore, we suggest that L. japonica mixed with IGF-1 could successfully be used to treat patients with alopecia; however, clinical trials and additional studies on the side effects of the mixture are necessary.