The collagen production of human dermal and corneal fibroblasts in contact with solutions of the peptide amphiphile (PA) C16-KTTKS is investigated and related to its self-assembly into nanotape structures. This PA is used in antiwrinkle cosmeceutical applications (trade name Matrixyl). We prove that C16-KTTKS stimulates collagen production in a concentration-dependent manner close to the critical aggregation concentration determined from pyrene fluorescence spectroscopy. This suggests that self-assembly and the stimulation of collagen production are inter-related.