Ulimorelin (INN, USAN) (developmental code name TZP-101) is a drug with a modified cyclic peptide structure which acts as a selective agonist of the ghrelin/growth hormone secretagogue receptor (GHSR-1a).

[1] Unlike many related drugs, ulimorelin has little or no effect on growth hormone (GH) release in rats.

[3] It has been researched for enhancing gastrointestinal motility, especially in gastroparesis[4] and in aiding recovery of bowel function following gastrointestinal surgery, where opioid analgesic drugs used for post-operative pain relief may worsen existing constipation.

[5][6][7][8] While ulimorelin has been shown to increase both upper and lower gastrointestinal motility in rats,[8] and showed promising results initially in humans,[4][6] it failed in pivotal clinical trials in post operative ileus.

[7] A common side effect of ghrelin is reduced blood pressure.