A derivative comprising a GLP-1 analogue having a Trp at a position corresponding to position 8 of GLP-1 (SEQ ID NO: 1) and wherein a substituent comprising at least eight consecutive -CH 2 -groups and at least one functional group with a pKa < 7 is attached to a Lys residue of the GLP-1 analogue; wherein the derivative is of formula I: (P-L) U -B-GLP1, wherein GLP1 is a GLP-1 analogue having a Trp at a position corresponding to position 8 of GLP-1 (SEQ ID NO: 1) comprising a peptide of the formula: Xaa 7 -Trp-Glu-Gly-Thr-Xaa 12 -Thr-Ser-Asp-Xaa 16 -Ser-Xaa 18 -Xaa 19 -Xaa 20 -Glu-Xaa 22 -Xaa 23 -Ala-Xaa 25 -Xaa2 6- Xaa 27 -Phe-Ile-Xaa 30 -Xaa 31 -Leu-Xaa 33 -Xaa 34 -Xaa 35 -Xaa 36 -Xaa 37 -Xaa 38 -Xaa 39 -Xaa 40 -Xaa 41 -Xaa 42, wherein Xaa 7 is L-histidine; Xaa 12 is Phe; Xaa 16 is Val; Xaa 18 is Ser; Xaa 19 is Tyr; Xaa 20 is Leu; Xaa 22 is Gly or Glu; Xaa 23 is Gin; Xaa 25 is Ala; Xaa 26 is Arg or Lys; Xaa 27 is Glu or Lys; Xaa 30 is Ala or Glu; Xaa 31 is Trp; Xaa 33 is Val; Xaa 34 is Arg; Xaa 35 is Gly; Xaa 36 is Arg or Lys; Xaa 37 is Gly, Lys, or Pro; Xaa 38 is Glu, Lys, or absent; Xaa 39 is Gly or absent; Xaa 40 is Gly or absent; Xaa 41 is Ser or absent; and Xaa 42 is Lys or absent; wherein (P-L) is the substituent attached to a Lys residue of the GLP-1 analogue via an optional Branching group and comprising a Protracting moiety and a Linker, U represents the number of substituents (P-L) in the derivative and is 1 or 2, wherein each substituent (P-L) comprises (i) a Protracting moiety selected from Chem. 10, Chem. 11, Chem. 12, Chem. 13, and Chem. 14: and (ii) a Linker comprising at least one linker element selected from Chem. 15, Chem. 16, Chem. 17, and Chem. 18: wherein R is -COOH; each of s, x, y, z, and p independently represents an integer in the range of 8-20; each of n, m, and q independently represents an integer in the range of 0-4; and each of k, I, and t independently represents an integer in the range of 1-5; and (iii) wherein the Branching group if present comprises a Branched linker selected from Chem. 19 and Chem. 20: wherein u and v independently represents an integer in the range of 0-5 and each w represents an integer in the range of 0-2, with the provisos that when u is 0 v is an integer in the range of 1-5, and when v is 0 u is an integer in the range of 1-5; which derivative is capable of activating the human GLP-1 receptor; or a pharmaceutically acceptable salt, amide, or ester thereof. Xaa 7 -Trp-Glu-Gly-Thr-Xaa 12 -Thr-Ser-Asp-Xaa 16 -Ser-Xaa 18 -Xaa 19 -Xaa 20 -Glu-Xaa 22 -Xaa 23 -Ala-Xaa 25 -Xaa2 6- Xaa 27 -Phe-Ile-Xaa 30 -Xaa 31 -Leu-Xaa 33 -Xaa 34 -Xaa 35 -Xaa 36 -Xaa 37 -Xaa 38 -Xaa 39 -Xaa 40 -Xaa 41 -Xaa 42, wherein Xaa 7 is L-histidine; Xaa 12 is Phe; Xaa 16 is Val; Xaa 18 is Ser; Xaa 19 is Tyr; Xaa 20 is Leu; Xaa 22 is Gly or Glu; Xaa 23 is Gin; Xaa 25 is Ala; Xaa 26 is Arg or Lys; Xaa 27 is Glu or Lys; Xaa 30 is Ala or Glu; Xaa 31 is Trp; Xaa 33 is Val; Xaa 34 is Arg; Xaa 35 is Gly; Xaa 36 is Arg or Lys; Xaa 37 is Gly, Lys, or Pro; Xaa 38 is Glu, Lys, or absent; Xaa 39 is Gly or absent; Xaa 40 is Gly or absent; Xaa 41 is Ser or absent; and Xaa 42 is Lys or absent; wherein (P-L) is the substituent attached to a Lys residue of the GLP-1 analogue via an optional Branching group and comprising a Protracting moiety and a Linker, U represents the number of substituents (P-L) in the derivative and is 1 or 2, wherein each substituent (P-L) comprises (i) a Protracting moiety selected from Chem. 10, Chem. 11, Chem. 12, Chem. 13, and Chem. 14: and (ii) a Linker comprising at least one linker element selected from Chem. 15, Chem. 16, Chem. 17, and Chem. 18: wherein R is -COOH; each of s, x, y, z, and p independently represents an integer in the range of 8-20; each of n, m, and q independently represents an integer in the range of 0-4; and each of k, I, and t independently represents an integer in the range of 1-5; and (iii) wherein the Branching group if present comprises a Branched linker selected from Chem. 19 and Chem. 20: wherein u and v independently represents an integer in the range of 0-5 and each w represents an integer in the range of 0-2, with the provisos that when u is 0 v is an integer in the range of 1-5, and when v is 0 u is an integer in the range of 1-5; which derivative is capable of activating the human GLP-1 receptor; or a pharmaceutically acceptable salt, amide, or ester thereof. (i) a Protracting moiety selected from Chem. 10, Chem. 11, Chem. 12, Chem. 13, and Chem. 14: and (ii) a Linker comprising at least one linker element selected from Chem. 15, Chem. 16, Chem. 17, and Chem. 18: wherein R is -COOH; each of s, x, y, z, and p independently represents an integer in the range of 8-20; each of n, m, and q independently represents an integer in the range of 0-4; and each of k, I, and t independently represents an integer in the range of 1-5; and R is -COOH; each of s, x, y, z, and p independently represents an integer in the range of 8-20; each of n, m, and q independently represents an integer in the range of 0-4; and each of k, I, and t independently represents an integer in the range of 1-5; and (iii) wherein the Branching group if present comprises a Branched linker selected from Chem. 19 and Chem. 20: wherein u and v independently represents an integer in the range of 0-5 and each w represents an integer in the range of 0-2, with the provisos that when u is 0 v is an integer in the range of 1-5, and when v is 0 u is an integer in the range of 1-5; which derivative is capable of activating the human GLP-1 receptor; or a pharmaceutically acceptable salt, amide, or ester thereof.