The copper(II) complex with GHK shows protective effects in bleomycin-induced pulmonary fibrosis, significantly decreasing the levels of proinflammatory cytokines and oxidative stress, by blocking the progression of epithelial–mesenchymal transition and repressing Transforming Growth Factor-beta1 (TGFβ1) and Suppressor of Mothers against Decapentaplegic2/3 (Smad2/3) signaling pathways [213]. Here, TGFB1 is linked to pulmonary fibrosis.