A certificate of analysis carries two dates and, on these certificates, only two: the date the laboratory received the sample and the date it issued the report. The issued date answers one question well — when was this material analysed, and is that analysis current for the lot in front of me? It answers no other question. It is not a manufacture date, it is not a fill date, and it is emphatically not an expiry. We checked all 114 certificates in our library on 29 September 2026: not one carries an expiry field, a retest field or a manufacture date.
The two dates, and what sits between them
| Field | What it records | What it is useful for |
|---|---|---|
| Received | The day the sample arrived at the laboratory | Anchoring the analysis in time, and the start of the turnaround interval |
| Issued | The day the laboratory released the report | Judging how current the analysis is for a given lot |
| (nothing else) | There is no expiry, retest, manufacture or fill date on any certificate in this library | — |
The interval between them is the laboratory's turnaround on that particular sample. It is the one thing a pair of dates gives you that a single date cannot.
What the turnaround actually looks like
Recomputed from the 114 certificates on file:
| Gap, received to issued | Certificates | Share |
|---|---|---|
| 6 days | 67 | 59% |
| 8 days | 20 | 18% |
| 10 days | 1 | 1% |
| 16 days | 26 | 23% |
| Range | 6 to 16 days | median 6, mean 8.7 |
The median is six days and our home page says so. It would be misleading to stop there. Most certificates were issued within a week of the sample arriving, and roughly a quarter took just over two weeks — a materially different picture from "about six days", and the honest way to describe a distribution with a lump at each end.
Two further points about the shape of it. The gaps cluster at 6, 8 and 16 days rather than spreading smoothly, and the 114 certificates carry only five distinct issued dates — 3 and 4 April, 17 and 25 June, and 17 August 2026. That pattern is consistent with samples being handled in batches rather than one at a time. We can see the pattern; we do not know what produces it, and we are not going to invent an explanation for a laboratory's internal scheduling.
None of the above is a commitment. It is a description of certificates that already exist. There is no published turnaround target for this laboratory, and a past median is not a promise about a future sample.
What the issued date does tell you
When the analysis happened. Every number on the certificate — purity, content, identity, endotoxin — is a measurement of one sample on one occasion. The issued date is the timestamp on that measurement, and it is the reason a certificate is evidence rather than a claim.
Whether the analysis is current for your lot. This is the use that matters to a buyer. A certificate issued for a lot you do not have describes material you did not receive. The pairing of lot number and issued date is what lets you establish that the document in front of you and the vial in your hand are about the same material.
Which of two certificates for one lot you are reading. That is not hypothetical here. P-21 5 mg, lot P21-5-0318, carries two certificates that are both in force: COA3388, issued 3 April 2026 against a white lyophilized powder with a four-test panel, and COA4866, issued 17 June 2026 against a clear liquid with sterility and heavy metals added. Same lot string, different sample form, different test panel, different reported purity. The P-21 post sets out both side by side. Without the issued dates, those two documents would be indistinguishable in a filing system.
What it does not tell you
Not when the material was synthesised. No certificate in this library records that. The lot code carries a numeric suffix that looks date-shaped — CJCIP10-0318, KISS10-0528, RETA48-0616 — but nothing on the certificate says what those digits refer to, so we will not read them as a date.
Not how long it will keep. There is no expiry line and no retest line, and an issued date does not imply one. The related question of what a label should say is already answered in the vial label post, which covers the expiry question directly; the chemistry of why a sealed lyophilised vial keeps as well as it does is in the storage guide.
Nothing about your vial's history. Everything after the sample left the laboratory — packing, transit, the hour it sat on a loading dock, your own freezer — is outside the document. Our cold-shipping post covers that half.
Nothing about the tests that were never run. A date says when the panel was performed, not how complete the panel was, which is the subject of what a certificate does not test for.
Why "certificate before listing" is the sequence that matters
The useful ordering is not certificate recent but certificate for this lot, issued before this lot went on sale. A supplier who tests a lot and publishes the result before selling it has done the thing that matters. A supplier showing you last year's certificate for this year's powder has not, however recent the document looks at a glance.
You can check that ordering yourself, and it takes about two minutes:
- Read the lot number off the vial. The label post covers where it sits and what it should look like.
- Find that lot in the certificate library. Each row shows compound, size, lot, issued date, purity, content and endotoxin, with a link to the PDF.
- Check the issued date against the lot you were sent. Certificates for earlier lots of the same compound sit below a separator on that page, marked as superseded — 43 of the 114 are in that group. They stay published because vials carrying those lot numbers exist and their owners still need the document.
- Verify the code with the laboratory. Each row links the certificate code through to Bioviridian's own lookup, which is the step that makes the document checkable rather than merely presentable.
- Read the month in bulk if you prefer. The lot reports for April, June and August 2026 group every certificate issued in that month.
What to make of an old issued date
Of the 71 certificates currently in force, 54 were issued on 17 August 2026 and six were issued on 3 April 2026 — the oldest being COA3378, for CJC-1295 + Ipamorelin 10 mg, lot CJCIP10-0318. Measured against the date of this post, that is close to six months.
That is a fact about a document, and the right response to it is a question rather than a conclusion. An older certificate on a listing can mean a slower-moving size, or a larger lot still being drawn down — both ordinary. What it should prompt you to ask is whether the lot you will receive is the lot that certificate describes. That is the question our supplier vetting post frames as the difference between a supplier selling from one large tested batch and a supplier not testing new ones.
We have no published rule about how old a certificate may be before a lot is re-tested, and we are not going to state one here, because none is recorded. What is recorded is every certificate, with both of its dates, for anyone who wants to check the sequence themselves.
Frequently asked questions
How old is too old for a certificate of analysis?
There is no general answer and no published rule on this site. Age alone is the wrong test: a six-month-old certificate for the exact lot you received is better evidence than a document issued last week for a different lot. The question to ask a supplier is which lot ships and whether the published certificate is the one for that lot.
Why do two certificates sometimes share a lot number?
Because a laboratory can analyse the same lot more than once, and under a different panel. The P-21 pair above is the example in this library: one certificate against a powder sample in April, one against a liquid sample in June with sterility and heavy metals added. Both are published unaltered, and the issued date is what distinguishes them. The lot-to-lot post covers why the numbers on two certificates rarely match exactly.
Does the issued date tell me how long the vial will keep?
No, and it should not be read that way. It records when a sample was tested. A sealed lyophilised vial's keeping qualities depend on temperature and on the seal holding, which the storage guide covers, and the label question is handled in the vial label post.
Why are superseded certificates left published?
Because vials bearing those lot numbers are in circulation, and the person holding one needs the certificate that describes it. Removing an old certificate when a new lot arrives would quietly strand every earlier buyer. They stay on the certificate page below a separator that says exactly what they are.
Every product referenced here is supplied for laboratory research use only and is not for human or animal use.
References
- Pepstral certificate library, src/coa.json. Point-in-time read of all 114 certificates on 29 September 2026: every entry carries a received and an issued date, no entry carries an expiry, retest or manufacture date, and the received-to-issued gap runs from 6 to 16 days. pepstral.com/coa.html
- Bioviridian Inc. Certificates of analysis COA3388 (issued 3 April 2026, white lyophilized powder) and COA4866 (issued 17 June 2026, clear liquid), both for P-21 5 mg lot P21-5-0318. pepstral.com/coa.html
- Bioviridian Inc. Certificate of analysis COA3378, CJC-1295 + Ipamorelin 10 mg, lot CJCIP10-0318, issued 3 April 2026 — the oldest issued date among the certificates currently in force. pepstral.com/coa.html
Every product mentioned is sold for laboratory research use only and is not for human or animal use. Nothing on this page describes or recommends use of the material sold here in humans or animals.
