BPC-157 Acetate

1 Identity

Tissue-repair and cytoprotective peptides. CAS 1628202-19-6 is the number one seller carries for the acetate; CAS 137525-51-0 also circulates for the same sequence.

Sequence

The same pentadecapeptide as the BPC-157 entry — H-Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val-OH, GEPPPGKPADDAGLV — isolated as its acetate salt rather than as the trifluoroacetate or the L-arginine salt. Acetate is a counterion held by ionic interaction with the two protonatable centers of the peptide, the N-terminal alpha-amino group and the Lys7 epsilon-amino group; it is not covalently attached, it is not an N-acetyl group, and this article is not N-acetyl-BPC-157. That distinction is the single most consequential fact in this record: the acetate salt and the N-acetylated peptide are different molecules, 42.04 Da apart on the peptide ion, and they are routinely confused in trade literature.

Molecular formula

Peptide C62H98N16O22; article C62H98N16O22 . X C2H4O2, with x determined on every lot. One seller prints the article formula in exactly this form, with the stoichiometry written as x — that is, undeclared at the catalog level. A specification written for an acetate article has to carry the salt formula C62H98N16O22 . X C2H4O2 and an acceptance range for x; where it states only the free-base formula and mass, a 5 mg nominal fill is undefined by between 4 percent and 8 percent.

Average mass

Peptide 1419.556 Da (C62H98N16O22) on IUPAC 2021 conventional atomic weights; 1419.53 also circulates, and the formula gives 1419.556. The article has no single average mass until x is fixed: at x=1 the salt is C64H102N16O24, 1479.608 Da, 95.94 percent net peptide; at x=2, C66H106N16O26, 1539.660 Da, 92.20 percent net peptide; at x=3, C68H110N16O28, 1599.712 Da, 88.74 percent net peptide. Two protonatable centers set the chemically sensible ceiling at two moles, and any lot certifying more than two should be asked to explain the third. The number that goes on the label is net peptide in mg, not salt mass.

Monoisotopic mass

Peptide 1418.7042 Da neutral; [M+H]+ m/z 1419.7115, [M+2H]2+ m/z 710.3594. The salt has no monoisotopic mass of its own in practice: acetate dissociates in the electrospray source and is never observed on the peptide ion, so the mass spectrum of this article is identical in every particular to that of the free peptide, of the trifluoroacetate salt and of the arginate. Mass spectrometry cannot distinguish any of the four salt forms, which is why counterion determination is a separate release test and not an inference from the mass spectrum.

Salt / variant note

(1) N-acetyl-BPC-157, C64H100N16O23, 1461.59 avg / 1460.71472 mono — the covalently acetylated peptide, +42.037 Da on the peptide ion. This is a different molecule from the acetate salt and it is the confusion this record exists to prevent; unlike the counterion, the N-acetyl group survives electrospray and is directly visible, so the two are trivially separable IF anyone looks. (2) the trifluoroacetate salt of the same peptide, sold under the same name, up to roughly 14 percent counterion by mass against 4.1 to 7.8 percent for the acetate — so a 10 mg vial of TFA salt and a 10 mg vial of acetate salt differ by roughly 0.7 mg of delivered peptide, and neither mass spectrum can tell you which you have. (3) the L-arginine salt, carried as its own article in the catalog, also sold as "BPC-157". (4) The free peptide with no counterion at all, which is not a normal article of commerce but is what a certificate implies when it prints C62H98N16O22 with no salt statement. (5) All backbone variants carried at the BPC-157 entry apply here identically: C-terminal amide -0.98 Da, des-Gly1 -57.02 Da, and the mass-silent Asp11-Gly13 isoaspartate. (6) stoichiometric variants of this article itself, x=1 to x=3, differing by 120 Da of formula weight and by 7.2 percentage points of net peptide, all sold as "BPC-157 acetate".

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.

The literature is that of the free peptide — a salt form has no separate literature, and no study identified specifies which salt was used. That absence matters: the rodent literature summarized in Vasireddi 2025 (systematic review) and McGuire 2025 (scoping review), the rat tendon work of Chang 2011, and the two registered human trials NCT02637284 (Phase 1, oral, results not posted) and NCT07437547 (Phase 2, subcutaneous, recruiting as of August 2026) do not state a counterion. The evidence base is graded D. No marketing authorization in any jurisdiction, no pharmacopeial monograph, and specifically no monograph that would fix an acetate specification.

4 Storage & specification

Storage

Lyophilized powder, -20 degrees C plus or minus 5 degrees C, desiccated with in-pack desiccant, sealed under nitrogen in amber or foil-overwrapped borosilicate serum vials, protected from light, handled below 30 percent relative humidity when open. The acetate salt is more hygroscopic than the trifluoroacetate, and water uptake in an opened vial directly changes the net peptide content on which the label claim rests, so the equilibrate-to-room-temperature-before-opening instruction is printed on the label and not left to the technical note. 2 to 8 degrees C is acceptable for transit and for working stock held no longer than 30 days.

Shelf life

Provisional 24 months at -20 degrees C plus or minus 5 degrees C, assigned by protocol. The indicating attributes are the Asp11-Gly13 isoaspartate content by the resolving RP-HPLC method, water by Karl Fischer, and acetate molar ratio — the last because acetate can be lost from an opened or poorly sealed vial, which raises apparent net peptide without any change in the peptide itself. Three-lot ICH Q1A protocol with a 6-month accelerated arm at 25 degrees C and 60 percent relative humidity; the interval is shortened on data and never extended without a completed dataset.