The synthetic peptides have the sequence: [RrA\ A2, A6, A8, A11, A12, A15, A20, A21, A22, Nle27, A28, A29, A30]hGH-RH(1 -30)-R2 (SEQ ID NO: 1 ) wherein R1 is Ac, Tfa, or is absent, A1 is Tyr, Dat, or N-Me-Tyr, A2 is Ala, D-Ala, Abu, or D-Abu, A6 is Phe or Fpa5, A8 is Asn, Ala, Gin, Thr, or N-Me-Ala, A11 is Arg, His, or Har, A12 is Orn, or Lys(Me)2, A15 is Abu or Ala A20 is Arg, His, or Har, A21 is Orn, or Lys(Me)2, A22 is Leu, or Orn, A28 is Ser, or Asp, A29 is Arg, Har, Agm, D-Arg, or D-Har, A30 is Arg, Agm, Ada, Amc, Aha, Apa, Har, D-Arg, D-Har, Gab, Gin, D-GIn, Gin-Gab, D-Gln-Gab, or is absent, R2 is -NH2, -OH, -NHR2, -N(R2)2, or -OR2, in which R2 is any of C1-12 alkyl, C2-12 alkenyl, or C2-12 alkinyl, provided that if A29 is Agm then A30 and R2 are absent A1 is N-Me-Tyr only, and pharmaceutically acceptable salts thereof.Linvention concerne les peptides synthétiques de séquence : [RrA\ A2, A6, A8, A11, A12, A15, A20, A21, A22, Nle27, A28, A29, A30]hGH-RH(1 -30)-R2 (SEQ ID NO: 1 ) où R1 est Ac, Tfa, ou est absent, A1 est Tyr, Dat ou N-Me-Tyr, A2 est Ala, D-Ala, Abu ou D-Abu, A6 est Phe ou Fpa5, A8 est Asn, Ala, Gin, Thr ou N-Me-Ala, A11 est Arg, His ou Har, A12 est Orn ou Lys(Me)2, A15 est Abu ou Ala, A20 est Arg, His ou Har, A21 est Orn ou Lys(Me)2, A22 est Leu ou Orn, A28 est Ser ou Asp, A29 est Arg, Har, Agm, D-Arg ou D-Har, A30 est Arg, Agm, Ada, Amc, Aha, Apa, Har, D-Arg, D-Har, Gab, Gin, D-GIn, Gin-Gab, D-Gln-Gab ou est absent, R2 est -NH2, -OH, -NHR2, -N(R2)2 ou -OR2, dans lequel R2 est lun quelconque parmi alkyle en C1-12, alcényle en C2-12 ou alcynyle en C2-12, à la condition que si A29 est Agm, alors A30 et R2 sont absents, A1 est N-Me-Tyr seulement, et les sels pharmaceutiquement acceptables de ces peptides.