Needle-free iontophoresis-driven β-adrenergic sweat rate test

•Iontophoresis provided successful transdermal delivery of drugs required to induce β-adrenergic sweat rate responses, including non-ionized or poorly ionized isoproterenol and aminophylline.•Modelling test responses by a nonlinear mixed-effects approach allowed evaluating metrics of CFTR-dependent effects while integrating inter- and intra-subject variability.•Secretory capacity and kinetic rate of CFTR-dependent sweating were blunted in CF. In carriers, kinetic rate was apparently lowered and secretory capacity was preserved.•The work promotes advances in the precision of biomarkers, needed to accelerate drug development in CF.