A supplier telling you it is legitimate is not evidence of anything — every supplier says that, including the ones that are not. So this page does the opposite of the usual: it sets out what can actually be checked about us, how to check it, and what a failed check would look like.
Proxiva Analytical DeskCertificate review, purity and identity testing
Key takeaways
- No vendor’s assurance about itself carries evidential weight. The only useful question is what can be independently verified, and how.
- Ask for a certificate matched to the batch you received — not a representative document for the product line. A supplier unable to produce one has answered the question.
- Read identity before purity. A purity figure attached to an unconfirmed identity describes some other molecule.
- Open the chromatogram rather than reading the headline percentage. Long peptides fail in ways a summary number does not show.
- Every test below applies to any supplier, us included. That is the point — a check that only works in our favour is not a check.
Why the usual answer to this question is worthless
Search whether any peptide supplier is legitimate and the results follow a pattern. The supplier’s own page explains that it is committed to quality, tests every batch, and maintains rigorous standards. Competitors’ pages explain the same about themselves.
None of that is evidence. Every one of those sentences is available to any vendor at no cost, including vendors shipping mislabelled material. A claim that costs nothing to make and cannot be checked carries no information, and a reader who accepts it has learned precisely nothing.
This creates an awkward position for a page like this one, published by the supplier being asked about. Any assurance offered here is subject to exactly the objection above, and adding emphasis does not repair it.
So the assurances are omitted. What follows instead is the set of checks that would expose us if we were not doing what we say — written so they can be run against us, and against anyone else selling the same material.
Check one: is the certificate tied to your batch
This is the single most informative question, and it separates suppliers faster than any other.
Every vendor can produce a certificate of analysis. The distinction that matters is whether the document describes the specific batch that shipped to you, or whether it is a representative certificate for the product line — a document generated once, from one synthesis, and supplied to every buyer thereafter.
A representative certificate tells you what one batch looked like at one time. It tells you nothing whatever about the vial in your hand, which came from a different synthesis, possibly a different facility, possibly a different year.
How to run the check: ask for the certificate corresponding to the lot number printed on your vial, and confirm the lot number on the document matches it. Not the product name — the lot.
What failure looks like: a document with no lot number, a lot number that does not match, a reply explaining that certificates are issued per product rather than per batch, or a delay long enough to suggest one is being prepared.
This check applies to every item in a catalogue. Run it on something inexpensive first — BPC-157 or KPV cost little and the answer generalises to everything else on the shelf.
Check two: read the document in the right order
Certificates are read incorrectly far more often than they are falsified, and the error is always the same.
Most readers look first at the purity percentage, because it is the largest number on the page and the easiest to compare. That is the wrong starting point, and it is wrong for a structural reason rather than a subtle one.
Purity is a ratio. It describes what proportion of the material is the intended compound relative to everything else present. It presupposes that the intended compound has been identified — and if that identification is absent or wrong, a purity figure of 99% describes 99% of something you did not order.
So read the mass spectrometry result first. It establishes identity: whether the molecule present is the molecule named. Only once that is settled does the purity figure mean anything.
- Confirm the lot number on the certificate matches the vial.
- Read the mass spectrometry result and confirm the observed mass matches the expected mass for the stated sequence.
- Then read chromatographic purity — as a trace, not as a headline figure.
- Confirm the stated quantity separately. Identity and purity establish what is present; neither establishes how much.
- Note who performed the analysis. A report from the facility that made the material is the weakest form of the document.
Check three: open the chromatogram
This is the check almost nobody runs, and it is where the informative failures live.
A chromatographic purity figure summarises a trace into a single number, and summarising discards the information that matters. What matters is not how much impurity is present but where it sits relative to the main peak.
Peptides are assembled one residue at a time, and chains that fail to extend at any step continue through the remaining steps as sequences missing a residue. Those deletion sequences differ from the intended product by a single amino acid — which means they are close in mass and close in retention time, appearing as shoulders or near-neighbours rather than as clearly separated peaks.
A headline purity figure may not distinguish them at all. A legible trace does.
This matters more for some products than others. A short sequence such as Epithalon or Selank has few couplings and little scope for the failure. A long one such as Retatrutide or Tesamorelin has many, and the trace is the only document that shows it.
What failure looks like: a certificate reporting a purity percentage with no chromatogram attached, or an image too low in resolution to read. A supplier that has run the analysis has the trace, and there is no reason to withhold it.
Check four: does the paperwork match the chemistry
A subtler signal, and a useful one because it is hard to fake convincingly.
Different classes of substance require different analyses. A synthesised peptide is characterised by mass spectrometry and reverse-phase chromatography. A metal complex additionally requires confirmation of the metal — GHK-Cu carries a coordinated copper ion, and the complex rather than the peptide alone is the functional species, so a certificate establishing only the peptide portion has verified half the molecule. A small molecule such as NAD+ is not a peptide at all and should not be characterised as one.
When a certificate applies peptide-shaped analysis to material that is not a peptide, or omits metal content for a metal complex, it indicates a document produced from a template rather than from an analysis of what was actually supplied.
That inference is worth more than any individual result on the page, because it describes the supplier’s process rather than one batch. A vendor generating documents will generate them consistently.
Run this check by comparing what the certificate measures against what the substance is. Blends require a further step: for a multi-component product such as Klow or Glow, confirm that quantity per component is reported and that the figures reconcile with the stated total. A certificate confirming four components are present and pure has verified an ingredient list and left the specification untested.
What these checks say about us, and what they do not
The checks above are not favourable to us by construction. They are the checks that would expose a supplier failing to do what it claims, which is why they are worth publishing and why most vendors do not.
What can reasonably be concluded from a page like this is limited and worth stating precisely. It demonstrates that the supplier knows what verification consists of, and is willing to hand a buyer the means to apply it. That is a behavioural signal rather than proof of anything about a given batch.
What it does not demonstrate is that any particular vial is what it claims to be. No page can establish that, published by anyone. Only the certificate for your batch can, which is why the first check is the first check.
The honest summary is therefore narrower than the question invites. Do not take our word for it. Order something inexpensive, run the four checks, and decide on the evidence. If we fail one, the failure will be visible to you and the cost of finding out will have been small.
That is the strongest claim any supplier can honestly make, and any supplier making a stronger one is telling you something about itself.
Frequently asked
Is Proxiva Peptides legitimate?
No answer we give to that question is evidence, because every supplier answers it the same way. What we can do is publish the checks that would expose us — batch-matched certificates, identity before purity, a legible chromatogram, and analysis appropriate to the chemistry — and invite you to run them on an inexpensive item first.
What should a certificate of analysis show?
A lot number matching your vial, identity by mass spectrometry, purity by chromatography with the trace included rather than only a percentage, and the stated quantity. For blends, quantity per component reconciled against the total. For metal complexes, confirmation of the metal.
Why does a representative certificate not count?
Because it describes a different batch from a different synthesis. It tells you what one production run looked like at one time and nothing about the vial you received.
Why read identity before purity?
Purity is a ratio describing what proportion of the material is the intended compound. If identity is unconfirmed, a high purity figure describes a large proportion of something you did not order.
What is wrong with a purity percentage on its own?
It summarises the trace into one number and discards where the impurities sit. Deletion sequences from a failed coupling differ by one residue, so they appear beside the main peak rather than away from it, and a headline figure may not separate them.
How do I test a supplier cheaply?
Order a low-cost single-component item, request the batch certificate before opening it, and run the four checks. The answer generalises to the rest of the catalogue, and the cost of learning it is small.
Verify these yourself
- Glow Pen 130mg/3ml — $175
- Klow Pen 145mg/3ml — $190
- Wolverine Blend Pen 30mg+20mg/3ml — $150
- Melanotan II Pen 50mg/3ml — $100
- MOTS-C Pen 60mg/3ml — $145
- TB-500 Pen 30mg/3ml — $175
- BPC-157 Pen 50mg/3ml — $125
Research use only. All products referenced on this page are sold strictly for laboratory and research purposes. They are not drugs, foods, cosmetics, or medical devices, and they are not intended to diagnose, treat, cure, or prevent any disease. They are not for human or veterinary consumption. Handling should be performed only by qualified individuals in an appropriate laboratory setting.