AbstractTripeptides containing lysine such as Arg‐His‐Lys (AHK) and Gly‐His‐Lys (GHK) are known to modulate biological regeneration. Here, we synthesized and evaluated the biological effects of dimeric peptide derivatives on the proliferation of human follicle dermal papilla cells (HFDPCs) in an in vitro model. Treatment of dimeric peptide derivatives stimulated the proliferation of HFDPCs more when compared to the group treated with AHK. Dimeric peptide derivatives also stimulated the phosphorylation of mitogen‐activated protein kinases extracellular signal‐regulated kinase (ERK1/2). In particular, peptide No. 20 Arg‐Trp‐Lys (AWK') was found to promote the phosphorylation of ERK1/2 most strongly. In addition, peptide No. 20 (AWK') activated mRNA expression of hair regeneration‐related genes such as VEGF, FGF‐2, and FGF‐7. Our results suggest that dimeric peptide derivatives exert a stimulating effect on HFDPC proliferation through activation of ERK1/2 signaling and without significant cytotoxicity. These results provide important data for the development of peptide‐based hair‐regenerative agents and treatment of alopecia.