The invention relates to a derivative of a GLP-1 analog, which analog comprises a first K residue at a position corresponding to position 18 of GLP-1(7-37) (SEQ ID NO: 1), a second K residue at another position, and a maximum of twelve amino acid changes as compared to GLP-1(7-37); which derivative comprises two protracting moieties attached to said first and second K residue, respectively, via a linker, wherein the protracting moiety is selected from Chem. 1, Chem. 2, and Chem. 3: HOOC—(CH2)x—CO—*  Chem. 1: HOOC—C6H4—O—(CH2)y—CO—*  Chem. 2: R2—C6H4—(CH2)z—CO—*,  Chem. 3: in which x is an integer in the range of 6-18, y is an integer in the range of 3-17, z is an integer in the range of 1-5, and R2 is a group having a molar mass not higher than 150 Da; and the linker comprises *—NH—(CH2)2—(O—(CH2)2)k—O—(CH2)n—CO—*.  Chem. 4: wherein k is an integer in the range of 1-5, and n is an integer in the range of 1-5; or a pharmaceutically acceptable salt, amide, or ester thereof. The invention also relates to the pharmaceutical use thereof, for example in the treatment and/or prevention of all forms of diabetes and related diseases, as well as to corresponding novel peptides and side chain intermediates. The derivatives are suitable for oral administration.