The Nrf2/Keap1 interaction is a target in the development of new therapeutic agents, where inhibition of the interaction activates Nrf2 and leads to the generation of downstream anti-inflammatory effects. Peptides that mimic the β-turn in the Keap1 active site and are constrained by a disulfide bridge have high affinity for Keap1 but no intracellular activity. The introduction of a perfluoroalkyl- bridging group to constrain the peptides, coupled with glutamic acid to proline replacement leads to a new peptide with a Ki of 6.1 nM for the Nrf2/Keap1 binding interaction, although this does not translate into intracellular activity