A reader comparison posted to r/PeptideNewsroom read ten peptide vendors' certificates of analysis side by side and ranked them on their paperwork alone. Not price, not catalogue size, not shipping speed, on the reasoning that none of those tell you what is in the vial.

Four criteria carried the weight, in order. Whether the certificate is batch-specific and published before purchase rather than offered on request, whether an independent laboratory is named on the document, whether it reports identity by mass spectrometry as well as purity by HPLC, and what else it bothers to measure. BPC-157 was the comparison compound throughout, because all ten sell it and the reports can be read like for like.

Where the paperwork thins

The bottom of that table is where the industry's habits show. Two of the ten publish nothing on their product pages at all and supply certificates only on request, and one of those two tests its own material in-house with no third party involved.

A third names no issuing laboratory on the document. A report with no lab on it cannot be checked by anyone, which makes that an editorial decision rather than an oversight.

One vendor documents four analytical methods and no mass spectrometry, which means identity is inferred rather than measured. Another keeps a properly public library whose most recent BPC-157 report is from October 2025, and a library only works if it tracks the batch actually shipping.

The test almost nobody buys

Measured net content is the striking absence. A purity figure describes how clean the peptide-related material is and says nothing about how much of it is in the vial, because water, residual solvents and counterions all sit outside that number.

The comparison found one vendor of ten reporting it. That single gap is why most per-milligram price comparisons in this market are comparing labels rather than contents, and it is worth knowing before anyone works out what they are paying per milligram.

Endotoxin is the other one. Most of the ten skip it, so its presence on a report says something about how far a vendor went before anyone made them.

Reading one yourself

The advice in the post is blunt and worth repeating. Batch-specific, named third-party laboratory, published before you pay, and if the lab prints a lookup code then use it and check the page that opens sits on the laboratory's own domain rather than the vendor's.

Purity and identity have to arrive together. A vial can be 99 per cent pure and still be 99 per cent pure something else, which is the whole reason mass spectrometry belongs on the document next to the chromatography.

Then match the batch number on the certificate to the number printed on the vial, the day the box arrives. A report for a different batch is not documentation of your product.

What the table cannot show

A certificate documents one batch at one moment. Good paperwork for this lot says nothing about the next one, and a clean report from a real laboratory still only covers the tests the vendor chose to pay for.

So this is a reading of ten documentation practices in 2026 rather than a verdict on the product in any particular box. On that narrow question the spread is wide, and it is entirely visible before anyone spends anything.

Disclosure. Peptriva sponsors this site and places first in the comparison described above, and the author of that comparison states a commercial relationship with Peptriva. Both facts belong beside the ranking rather than under it.