High-frequency double electron-electron resonance (DEER) distance measurements using different Gd3+ tags (Gd-DOTA and Gd-C1) were carried out on transmembrane helical peptides (ca. 0.15-nmol; WALP peptides) in a model membrane. The ability to pick up small distance variations, the chemical flexibility of the tags, and the remarkable absolute sensitivity, make this approach attractive for studies of membrane proteins. Copyright ? 2013 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim.