AOD-9604

1 Identity

Growth-hormone-derived synthetic peptide fragment with one intramolecular disulfide. Traded interchangeably — and incorrectly — as "hGH fragment 176-191", which is a different molecule.

Sequence

H-Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe-OH — one-letter YLRIVQCRSVEGSCGF. Sixteen residues, all L. Free N-terminal alpha-amino group on the appended tyrosine; free C-terminal carboxyl on Phe16. One intramolecular disulfide, Cys7-Cys14 in this numbering, corresponding to hGH Cys182-Cys189. No acetylation, no amidation, no non-proteinogenic residue. Supplied as the acetate salt — one reagent catalog writes the article as C78H123N23O23S2 . XC2H4O2 with X unspecified — or as the trifluoroacetate. The N-terminal tyrosine is an appended, non-native residue: it does not reconstitute hGH position 176, which is phenylalanine.

Molecular formula

C78H123N23O23S2 (disulfide-closed free base)

Average mass

1815.100 Da (C78H123N23O23S2).

Monoisotopic mass

1813.86036 Da. [M+H]+ m/z 1814.8676; [M+2H]2+ m/z 907.9375; [M+3H]3+ m/z 605.6274.

Salt / variant note

Three chemically distinct molecules circulate under overlapping trade names, and the market's own alias line propagates the error. (1) AOD-9604 proper, Tyr-hGH(177-191): C78H123N23O23S2, 1815.10 average / 1813.8604 monoisotopic. (2) TRUE hGH fragment 176-191. Position 176 of mature 191-residue hGH is phenylalanine, not tyrosine — the native fragment is H-Phe-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe-OH, C78H123N23O22S2, 1799.10 average / 1797.8654 monoisotopic. It has the identical carbon, hydrogen, nitrogen and sulfur count as AOD-9604 and differs by exactly one oxygen, 16.00 Da. The N-terminal tyrosine of AOD-9604 is therefore a non-native appended residue and does not reconstitute hGH position 176; the trade practice of selling the two names interchangeably substitutes a 1799 Da molecule for an 1815 Da one, and the 16 Da offset is the same magnitude as a methionine or tyrosine oxidation, so an analyst working from habit will read it as a degradation product rather than as the wrong peptide. (3) hGH(177-191) with no N-terminal addition, C69H114N22O21S2, 1651.92 average / 1650.7970 monoisotopic — 163.18 Da lighter, sold as "HGH Fragment 177-191". Two further process variants sit within one nominal mass of the target: fully reduced AOD-9604 with two free thiols, C78H125N23O23S2, 1817.12 / 1815.8760, plus 2.02 Da; and the C-terminal amide, C78H124N24O22S2, 1814.12 / 1812.8763, minus 0.98 Da. Disulfide-scrambled monomer and covalent dimer are exactly isobaric with the target and invisible to accurate mass entirely.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

In-vitro and rodent literature, plus a completed sponsor-run clinical program by the original Australian developer comprising dose-ranging work and a 12-week randomized placebo-controlled Phase IIb study, reported in a small number of peer-reviewed papers and reviews. Development was discontinued and there is no marketing authorization in any jurisdiction. No second sponsor has replicated the human work and no controlled human study of any size has been published in the last decade.

4 Storage & specification

Storage

Lyophilized powder, -20 degrees C plus or minus 5 degrees C, desiccated, protected from light, in the sealed original vial. Disulfide-containing peptides degrade under freeze-thaw cycling and in alkaline solution, so the vial ships and is stored dry and no reconstituted presentation exists. These are the conditions under which the article is filled, labeled and stored.

Shelf life

Provisional 18 months at -20 degrees C plus or minus 5 degrees C, shorter than the catalog default for linear peptides because of the disulfide, with disulfide-scrambled and dimeric species by SE-HPLC and total related substances as the stability-indicating attributes. This provisional interval is the retest date printed on the label, limited by the stability-indicating attributes named above.