What is Ipamorelin?

Five amino acids and a development code

Ipamorelin is a wholly synthetic pentapeptide: five amino-acid units linked into a short chain. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, and its development code was NNC 26-0161. The design came from GHRP-1 by removing the central Ala-Trp pair; the original characterization describes the resulting selective growth-hormone secretagogue.

There is economy in that origin that I admire. A shorter sequence still produced a strong GH response, with less stimulation of the other hormones measured. The molecule’s later reputation can obscure how specific that original achievement was.

“Ipamorelin acetate” identifies a salt form. The extra word changes the chemical description, while the need for evidence about clinical use remains.

From hormone research to bowel recovery

The animal characterization appeared in 1998; human pharmacokinetics followed in 1999. The later clinical programme concerned postoperative ileus, temporary bowel slowing after surgery. The published Phase 2 study in 2014 missed its primary endpoint.

A history told entirely around anti-aging or body composition sits awkwardly beside that sequence. The clinical problem that actually received a published randomized trial was recovery of bowel function. Claims about sleep, muscle or fat loss need their own clinical results.

Is Ipamorelin FDA approved?

Ipamorelin has no FDA-approved indication and has never been approved as a drug by any regulatory authority. Compounding status and drug approval are separate regulatory questions.

On FDA’s page current as of April 22, 2026, ipamorelin acetate appears in Category 2 under the 503B interim policy and in a separate table of substances whose nominations were withdrawn. FDA supplies no withdrawal date. That record leaves its safety warnings in place; withdrawal of a nomination provides no clearance.

At the October 29, 2024 Pharmacy Compounding Advisory Committee meeting, the vote was 0 yes, 12 no and 1 abstention against placing each form on the 503A Bulks List. As of October 1, 2026, FDA had published no rule, and neither form appeared on the 503A or 503B Bulks List.

For me, regulatory acceptance would be an extraordinary description of that record. A statement about a withdrawn nomination needs the surrounding status, including the continuing 503B listing.

Sport and research labels

Ipamorelin is prohibited in sport at all times under WADA category S2. The critical review of peptide use in sport discusses its promotion, safety concerns and the detection framework. The short blood half-life supplies no assurance about avoiding an anti-doping test.

A research label establishes no approved human use and offers no proof of pharmaceutical identity, purity or sterility. I would want those quality questions settled separately from any argument about the molecule’s mechanism. The safety page explains the clinical gaps.