The pathogenesis of primary focal hyperhidrosis (PFH) is still not clear. PFH is thought to be a genetic disease. Whether activin A receptor type 1 (ACVR1) is involved in the pathogenesis of PFH is unknown. In this study, the expression of ACVR1 in sweat glands of patients with PAH was detected by western blot and immunofluorescence. The primary sweat gland cells obtained from primary axillary hyperhidrosis (PAH) patients were transfected with acvr1 vector. Cell proliferation, apoptosis and cell cycling of gland cells were measured after transfection with acvr1 vector. The mRNA and protein expression of aquaporin 5 (AQP5) and Na:K:2Cl Cotransporter 1 (NKCC1/SLC12A2) were detected. Our data showed that ACVR1 expression in axillary sweat gland tissue of PAH patients was significantly higher than that of normal control group. The function of ACVR1 was further investigated in the gland cells obtained from PAH patients. Compared with NC group, ACVR1 overexpression significantly promoted the proliferation of sweat gland cells and inhibited the apoptosis of sweat gland cells. Meanwhile, ACVR1 overexpression significantly reduced the percentage of cells in G0/G1 and G2/M phases, and increased the percentage of cells in S phase. In addition, ACVR1 overexpression significantly promoted the expression of AQP5 and NKCC1 at both mRNA and protein levels. Together, ACVR1 expression is related to PFH and ACVR1 overexpression can promote the proliferation of sweat gland cells and inhibit apoptosis by promoting the expression of AQP5 and NKCC1. (C) 2020 Elsevier Inc. All rights reserved.