Ipamorelin in 2026: FDA Category 2 Status, Sequence and Non-Coded Residues

Ipamorelin acetate is in Category 2 of FDA's interim compounding policies under section 503B, with a date added of September 29, 2023, on the FDA page whose content is current as of April 22, 2026. Ipamorelin is a synthetic pentapeptide amide, H-Aib-His-D-2-Nal-D-Phe-Lys-NH2 (C38H49N9O5, 711.85 g/mol, CAS 170851-70-4), and three of its five residues are not among the 20 standard L-amino acids. Of every compound Pepta Labs lists, it is the only one named in that Category 2 table.

What is the FDA status of ipamorelin in 2026?

On September 24, 2026, the FDA compounding page that holds the Category 2 table of the interim policies (content current as of April 22, 2026) shows "Ipamorelin acetate" in that table, with 503B in its category column and a date added of September 29, 2023. The same page also names ipamorelin acetate in its separate table of substances nominated but withdrawn, with a note that it still appears in the Category 2 table because it is in Category 2 under the 503B interim policy.

September 29, 2023 is the date on which FDA added a group of peptides to Category 2. On the April 22, 2026 page, ipamorelin acetate is one of four peptides with a date added of September 29, 2023 in the Category 2 table, and none of the other three is listed by Pepta Labs. The 503A and 503B category lists concern compounding by state-licensed pharmacies and physicians (503A) and by outsourcing facilities registered with FDA (503B). This page records the FDA entries with their dates and states no legal opinion. The status of every peptide named on September 29, 2023 is tabulated in FDA Category 2 peptides 2026, and the wider picture is in peptide legal status 2026.

What is the sequence of ipamorelin?

The sequence of ipamorelin is H-Aib-His-D-2-Nal-D-Phe-Lys-NH2, written in full as 2-methylalanyl-L-histidyl-3-(2-naphthyl)-D-alanyl-D-phenylalanyl-L-lysinamide. "H-" marks a free N-terminal amine and "-NH2" marks a C-terminal primary amide in place of a free acid; peptide sequence notation explains both conventions.

CAS 170851-70-4, C38H49N9O5 and 711.85 g/mol all describe the free base. Ipamorelin has three basic sites (the N-terminal amine, the histidine imidazole and the lysine side-chain amine), so a salt can carry more than one counter-ion per peptide and weighs more per molecule than 711.85. TFA vs acetate and net peptide content covers the difference; net peptide content is not reported per listing.

Which residues in ipamorelin are non-coded, and how do they show on a mass spectrum?

A non-coded residue is an amino acid other than the 20 standard (proteinogenic) L-amino acids. Ipamorelin has three: 2-aminoisobutyric acid (Aib, 2-methylalanine) at position 1, 3-(2-naphthyl)-D-alanine (D-2-Nal) at position 3 and D-phenylalanine at position 4. Only histidine and lysine are standard L-amino acids.

The five residue masses plus NH3 for the free N-terminus and the C-terminal amide sum to C38H49N9O5. Aib and D-2-Nal together add 64.0313 Da, so a pentapeptide amide built only from coded residues in the same pattern (Ala-His-Phe-Phe-Lys-NH2) would sit near 647.35 Da, not 711.39. That is the mass signature a report should show: a deconvoluted monoisotopic mass of 711.39 Da, or 711.85 on an average-mass scale.

The D-residues leave no mass signature. D-Phe and L-Phe share the formula C9H9NO, and a peptide with L-2-Nal or L-Phe at positions 3 or 4 has exactly the same mass as ipamorelin. Such diastereomers can differ in RP-HPLC retention, and chiral amino-acid analysis after hydrolysis assigns configuration directly; mass spectrometry alone cannot. Mass spectrometry and peptide identity covers this limit for every listing.

Calculated ions for ipamorelin

These values are calculated from C38H49N9O5 with monoisotopic atomic masses (C 12.000000, H 1.0078250, N 14.0030740, O 15.9949146) and a proton mass of 1.0072765. The counter-ion is not part of the observed peptide mass, because the salt dissociates in the ion source. The expected mass table lists the same columns for every listed compound.

How is ipamorelin listed and documented?

Both listings show the same identity record: CAS 170851-70-4, C38H49N9O5, 711.85 Da and the sequence above, as lyophilized powder in a sealed glass vial. Testing is independent third-party HPLC purity analysis and mass-spectrometry identity confirmation, commissioned through the purchasing group on a sampled production run from the source; Pepta Labs does not test in-house. Vial labels identify the compound, quantity and research-use designation and do not carry lot or batch numbers. The report is sent by email on request, before an order if wanted, through the report request form; how to verify a peptide COA lists the fields to check. Cost per milligram across sizes is compared on the research peptide price per mg page, and sealed-vial storage is covered in the peptide storage guide. For what a research peptide is and how listings are described, start with what are research peptides.

Frequently asked questions

Is ipamorelin on the FDA Category 2 list in 2026?

Yes. The FDA page with content current as of April 22, 2026 shows ipamorelin acetate in its Category 2 table under the 503B interim policy, date added September 29, 2023, and the 503B category list updated March 21, 2025 also places ipamorelin acetate in Category 2.

Is ipamorelin the same compound as tesamorelin?

No. Ipamorelin is a 5-residue peptide amide, C38H49N9O5, 711.85 g/mol, CAS 170851-70-4, containing Aib, D-2-Nal and D-Phe. Tesamorelin is a 44-residue peptide amide built only from coded amino acids (all L-configured apart from achiral glycine) with an N-terminal trans-3-hexenoyl group, C221H366N72O67S, 5135.86 Da, CAS 218949-48-5 (the acetate is CAS 804475-66-9), UNII MQG94M5EEO. Tesamorelin is about 7.2 times heavier, and the ipamorelin sequence does not occur within it.

What ions should an ipamorelin mass spectrum show?

From the monoisotopic mass of 711.3857 Da, the calculated ions are [M+H]⁺ at m/z 712.39, [M+2H]²⁺ at m/z 356.70 and [M+3H]³⁺ at m/z 238.14, with a possible sodium adduct [M+Na]⁺ at m/z 734.37. The counter-ion does not appear in the peptide mass.

Is the 10 mg vial the same material as the 5 mg vial?

Both listings show the same compound record (CAS 170851-70-4, C38H49N9O5, 711.85 Da, H-Aib-His-D-2-Nal-D-Phe-Lys-NH2) and the same reported 99.2% RP-HPLC purity. They differ in nominal quantity, 5 mg or 10 mg per vial, and in price. The report covers the sampled production run, not an individual vial.

How many residues does ipamorelin have?

Ipamorelin has five residues: Aib, His, D-2-Nal, D-Phe and Lys, with a C-terminal primary amide. Three of the five (Aib, D-2-Nal and D-Phe) are not among the 20 coded L-amino acids.

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