BPC-157 testing: purity, mg per vial, salt forms and why half of published samples fail

What a BPC-157 test shows

A BPC-157 test should give three results. LC-MS shows whether the main peptide has BPC-157’s mass. HPLC shows how pure it is. A content assay shows how many mg of BPC-157, as free base, the vial holds. If the vials are for injection research, endotoxin and sterility are separate tests on their own unopened vials.

Test	What it answers for BPC-157	Reported as
Identity (LC-MS)	Measured mass against the calculated monoisotopic mass, 1418.7042 Da	Expected and observed mass, error in ppm
Purity (HPLC)	Main peak as a share of UV peak area	% area, with impurity peaks
Content per vial	mg of BPC-157 as free base, against a reference standard	mg per vial, uncertainty, % of label
Counter-ion (powder)	Share of TFA or acetate in the powder	% of the powder
Endotoxin (LAL)	Endotoxin in the sample	EU per mg and EU per vial
Sterility (USP <71>, 14 days)	Microbial growth over at least 14 days of incubation	Growth or no growth, units tested

BPC-157 is a synthetic pentadecapeptide: 15 amino acids, sequence GEPPPGKPADDAGLV, formula C62H98N16O22. The BPC-157 compound page lists the CAS number (137525-51-0) and the ions an LC-MS run looks for, at m/z 710.3594 (2+) and 473.9087 (3+), both calculated.

BPC-157 test results: about half of published samples fail

Finnrick, a US platform, publishes lab results for samples that buyers and others send in. In its data to 20 September 2026, BPC-157 had 791 published tests: 391 passed, 395 failed and 5 were incomplete. That is about 50% of classifiable samples, and more fails than passes.

For comparison, retatrutide failed about 22% and GHK-Cu about 13% in the same data. Tesamorelin (54%) and CJC-1295 (72%) failed more often, and so did TB-500 (175 of 282 tests in Finnrick’s snapshot of 25 September 2026).

Finnrick’s default standard, Purity Focus, passes a sample only if the identity is right, purity is at least 99.5%, and the fill is within ±35% of the label claim. Overfill fails as well as underfill. The published counts do not say which requirement each failed sample missed, so a fail can be a wrong peptide, an empty vial, a 99.0% purity result or a vial at half its label. The guide to peptide fail rates compares more products and explains the caveats.

How a lab confirms BPC-157 identity

BPC-157 is small next to the GLP-1 peptides: about 1,419 Da against about 4,100 to 4,800 Da for semaglutide, retatrutide and tirzepatide. Its doubly charged ion at m/z 710.36 is easy to measure, and the sequence is fully known, so an observed mass that matches within a few ppm is strong evidence of the right molecule.

Two limits remain:

• Retention time alone is not proof. ICH Q6A says retention time alone “is not regarded as being specific”. A UV peak at the expected time says nothing about the mass.
• Mass cannot see isomers. A version of the peptide with one D-amino acid has exactly the same mass. Only the HPLC separation can show it, which is why identity and purity are two tests.

Salt forms: acetate, arginate and free base

BPC-157 is sold as different salt forms, such as the acetate and the arginate. The salt adds weight to the powder without adding peptide. The FDA’s Pharmacy Compounding Advisory Committee, at its meeting on 23 July 2026, listed BPC-157 as two named substances: BPC-157 (free base) and BPC-157 acetate.

For a test result, the basis decides the number. Content as free base counts only the BPC-157 itself. A result calculated on total powder reads higher, because it includes the counter-ion and water. A good report states its basis, and a counter-ion test measures how much of the powder is TFA or acetate. The guide on net peptide content works through the numbers.

Oral BPC-157 and capsules

Some searches ask for oral BPC-157 that is third party tested. Capsules and tablets hold fillers, binders and coatings next to the peptide. The lab has to separate the peptide from that matrix before it can measure it, and excipients can add peaks to the chromatogram that are not BPC-157 impurities. Not every lab has a method for this. Tell the lab the form and the listed ingredients before you send anything, and ask whether the result is given as mg per capsule.

BPC-157 blends

BPC-157 is often sold in blends, for example with TB-500. Some labs list blend tests as their own products; Janoshik’s peptide list includes a BPC-157 and TB-500 blend. A blend needs identity and mg for each component. One purity figure for the whole vial means little, because the mix is by design. See the guide to peptide blend testing.

Third party tested claims and tested brands

“Third party tested” on a product page usually means the seller sent a sample to an outside lab. That report covers the sample the seller chose. Before you rely on it:

1. Match the lot number on the report to the lot on your vial.
2. Open the report on the lab’s own site, not from a screenshot.
3. Look for an observed mass, a chromatogram and mg with a stated basis.
4. Check the date. A report from an older batch says nothing about a new one.

The guide on vendor COAs versus testing your own vial covers the difference. Many labs accept samples by post from other countries. The guide to peptide testing in Australia covers options for Australian buyers. Declare samples accurately and follow the courier’s rules.

How to get BPC-157 tested

Request a quote with the product form and the tests you want. The quote states how many vials to send; endotoxin and sterility each need their own unopened vials. Ship the vials sealed and numbered. For a group test, take vials at random from different kits and send three or more, so the result shows how much vials differ.

What HK Analytical does for BPC-157

We test BPC-157 as one sample with any mix of identity (LC-MS), purity (HPLC), content per vial, endotoxin (LAL), Sterility (USP <71>, 14 days), residual solvents, counter-ion (TFA, acetate), water content (Karl Fischer) and vial-to-vial consistency. Content is reported as free base. We do not offer per-component blend analysis. Results within days of receipt. Sterility (USP <71>, 14 days) is the one test that takes 14 days, because the method incubates for 14 days. Every number comes with its raw data, and each report is a signed record you can check at hkanalytical.com/verify. Request a quote to start.