Source Safety

Peptide Source Checker

Where a peptide comes from predicts more about your risk than anything printed on the vial. Answer the checks below and this tool will score your source, name the gaps, and write the questions you should be sending.

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Peptide Source Checker

Step 1 — Where does it come from?

This is the single most important question, and it changes which checks apply. An approved drug from a licensed pharmacy needs no certificate of analysis. A research-chemical vial needs a great deal more than one.

An FDA-approved drug, prescribed to me, from a state-licensed pharmacy The approved supply chain: a drug FDA has reviewed, prescribed for you, dispensed by a pharmacy a state regulator licenses. Compounded by a pharmacy or outsourcing facility (503A / 503B) A pharmacy prepared it. Compounded drugs are not FDA-approved and are not reviewed for safety or effectiveness before marketing. A "research use only — not for human consumption" supplier The grey market. No regulator has reviewed the product, and the label explicitly disclaims human use. I am not sure where it comes from If you cannot say which of the three above applies, that is the finding.

Step 2 — Run the checks

Answer honestly. “Not sure” is not a neutral answer — not knowing is itself a risk, and the tool will tell you how to find out.

A licensed clinician prescribed it for you by name Deal-breaker

yes no Not sure

A prescription written for you is what ties the product to a diagnosis, a dose, and someone accountable for both. A "prescription" issued by the same company selling the drug, after a form with no examination, is a sales step wearing a clinical costume.

The pharmacy is verified in a state board of pharmacy licence database Deal-breaker

yes no Not sure

FDA’s BeSafeRx guidance is blunt: check the pharmacy’s licence in the state board database. If the pharmacy is not listed, do not use it. Illegal online pharmacies copy the look of real ones convincingly.

The exact product appears in Drugs@FDA with a matching NDC number

yes no Not sure

An FDA-approved product has a National Drug Code and an approval record you can look up yourself. If you cannot find the product in Drugs@FDA, it is not an FDA-approved drug, whatever the label implies.

It arrived in sealed manufacturer packaging with intact tamper evidence

yes no Not sure

Repackaged, unlabelled, or loose vials break the chain of custody that makes an approved drug trustworthy. Tamper evidence exists precisely so that you can tell.

Lot number, expiry, and label formatting match the manufacturer’s

yes no Not sure

FDA seized counterfeit Ozempic that carried a genuine lot number — the counterfeits were identifiable only by where the EXP/LOT text sat on the label. Matching a lot number is necessary but not sufficient; compare the label against the manufacturer’s reference images.

A licensed pharmacist is reachable and answers clinical questions

yes no Not sure

A real pharmacy has a pharmacist who will talk to you about interactions, storage, and administration. An operation that only offers a support ticket form is not a pharmacy.

It shipped cold (if required) and arrived cold, within its expiry

yes no Not sure

FDA has documented compounded and mail-order GLP-1 products arriving warm or with inadequate ice packs. Temperature excursions can degrade a peptide silently — the vial looks identical.

Step 2 — Run the checks

Answer honestly. “Not sure” is not a neutral answer — not knowing is itself a risk, and the tool will tell you how to find out.

The compounding facility is named, and is a state-licensed 503A pharmacy or an FDA-registered 503B outsourcing facility Deal-breaker

yes no Not sure

FDA has found fraudulent compounded semaglutide and tirzepatide whose labels named compounding pharmacies that do not exist, or that name a real pharmacy which never compounded the product. A facility you cannot name and verify is not a facility.

It was compounded against a patient-specific prescription Deal-breaker

yes no Not sure

A 503A pharmacy may compound for an individual patient with a prescription. Mass-marketed compounded product sold without one is operating outside the framework that permits compounding at all.

It is the base peptide — not an unapproved salt form Deal-breaker

yes no Not sure

FDA has specifically flagged semaglutide sodium and semaglutide acetate. These are different active ingredients from the one in the approved product; safety and effectiveness data for the approved drug do not transfer to them.

The active ingredient is sourced from an FDA-registered facility

yes no Not sure

FDA has warned that some compounders use active ingredients imported from plants that FDA has never inspected. The finished product cannot be cleaner than the ingredient it starts from.

Sterility and endotoxin testing is documented for the batch

yes no Not sure

Anything you inject must be sterile and free of bacterial endotoxin. For sterile compounded products this testing is not optional, and the results should be available for your batch.

The vial carries a beyond-use date and storage instructions

yes no Not sure

Compounded products get a beyond-use date, not a manufacturer expiry. Without one you have no basis for judging whether the product is still what the label claims.

Dosing instructions for the vial are unambiguous, in the units marked on your syringe

yes no Not sure

FDA has received hundreds of adverse event reports involving dosing errors from compounded multi-dose vials — people drawing up ten times the intended dose because instructions were given in milligrams while the syringe reads in units.

Step 2 — Run the checks

Answer honestly. “Not sure” is not a neutral answer — not knowing is itself a risk, and the tool will tell you how to find out.

The COA is batch-specific, and its lot number matches the vial you will receive Deal-breaker

yes no Not sure

A generic COA, or one reused across lots, tells you about a batch you did not buy. If the vendor cannot say which batch your vial came from and show the matching certificate, the certificate is decoration.

The COA is from a named independent laboratory, not the vendor’s own lab Deal-breaker

yes no Not sure

An in-house COA is a self-report by the party with a commercial interest in the result. Only a certificate from an independent lab, named on the document, is third-party verification.

The COA includes the actual HPLC chromatogram, not just a purity percentage Deal-breaker

yes no Not sure

A bare number cannot be checked by anyone. The chromatogram is the evidence. Note the inverse tell too: real chromatograms have baseline noise and purity varies batch to batch, so a flawless trace and an identical 99.9% on every product suggest a document that was designed rather than measured.

Mass spectrometry confirms identity (observed mass vs. theoretical mass)

yes no Not sure

HPLC purity tells you how much of the sample is one substance. It does not tell you that the substance is the peptide you ordered. Only mass spectrometry confirms identity.

Net peptide content and salt form are stated — not just a purity figure

yes no Not sure

Purity and content are different measurements, and conflating them is the most common misunderstanding in this market. Purity compares the peptide to other peptide-like impurities. Net content compares the peptide to everything in the vial — water, counter-ions, salts, bulking agents. A vial can be 99% pure and still be 70% peptide by mass, because the HPLC detector never sees the mannitol.

The COA can be verified directly with the issuing laboratory

yes no Not sure

Independent labs publish their results in a public database keyed to an identifier printed on the certificate — typically a task or report number plus a case-sensitive unique key. If those credentials return nothing on the lab’s own portal, the certificate was fabricated. Fake COAs are common enough that this step is worth the two minutes.

The analysis date is recent and belongs to the batch being sold

yes no Not sure

Peptides degrade. A certificate from three years ago describes a batch, and a condition, that no longer exists.

Heavy metals and endotoxin testing is available (for anything injected)

yes no Not sure

Purity testing looks at peptide-related impurities. It is blind to heavy metals and bacterial endotoxin, which are tested by separate methods and which matter enormously for an injected product.

There is a verifiable business entity: physical address and a working phone number

yes no Not sure

Anonymous operations with no address, no registered entity, and an email-only contact can disappear between your payment and your delivery — and routinely do.

Credit card payment is accepted — not crypto or peer-to-peer cash only

yes no Not sure

This is less about payment convenience and more about recourse. A card payment can be charged back. A crypto transfer cannot. Vendors who accept only irreversible payment methods have chosen a world where you have no remedy.

Support answers specific technical questions about lot, lab, and method

yes no Not sure

The questions in this tool are the test. A source that handles them directly is a different kind of operation from one that responds with marketing copy.

Storage and shipping conditions are documented, and it arrives as described

yes no Not sure

Lyophilised peptide is reasonably stable; reconstituted peptide is not, and neither survives arbitrary heat. A vendor with no stated handling conditions is telling you they do not track them.

Red flag: every product is advertised at an identical, near-perfect purity

yes no Not sure

Real analysis produces variation. Honest figures cluster somewhere around 98–99.2% and move from batch to batch. A catalogue where everything is exactly 99.9% is describing a marketing decision, not a measurement.

Red flag: pricing is far below the established market rate

yes no Not sure

Underdosed and adulterated product is cheaper to make. A price well below everyone else is a claim that the vendor has solved a chemistry problem their competitors have not — and is more often a claim about what is really in the vial.

Red flag: the seller makes therapeutic or dosing claims about a "research only" product

yes no Not sure

A vendor cannot simultaneously claim the product is not for human consumption and tell you how to dose it for weight loss. That contradiction is a legal shield for them, and it should tell you how much of the rest of their labelling is load-bearing.

Red flag: pressure tactics, or the COA only appears after payment

yes no Not sure

Resetting countdown timers, "COA available on request" that never arrives, cloned product copy, and brand-new domains impersonating shut-down vendors are the standard toolkit. Buyers are rarely fooled by chemistry; they are fooled by presentation.

Establish where the product comes from before evaluating anything else about it. Ask the seller directly: is this an FDA-approved drug dispensed against a prescription, a compounded preparation, or a research chemical? If nobody will answer plainly, you have your answer.

Nothing you enter here leaves your browser. Pepperz does not test, rank, endorse, or sell any product or vendor, and does not provide medical advice.

What actually predicts risk

Channel first. Paperwork second.

Approved and dispensed

A drug FDA reviewed, prescribed for you, dispensed by a pharmacy a state regulator licenses. Someone inspected the plant. Someone is accountable. Counterfeits still reach this chain, so the packaging checks matter — but the floor is far higher.

Compounded

Prepared by a pharmacy rather than approved by a regulator. FDA does not review compounded drugs for safety, effectiveness, or quality before sale. It has documented fraudulent products naming compounding pharmacies that do not exist.

Research use only

Nothing has been reviewed, and the label disclaims human use. Diligence here is real and worth doing — it just cannot manufacture the oversight that was never applied.

How to read a COA

Purity is not content, and a number is not evidence.

Purity ≠ net peptide content

This single confusion causes more misplaced confidence than anything else in the field. Purity compares the peptide against other peptide-like impurities from synthesis. Net peptide content compares the peptide against everything else in the vial — water, counter-ions, salts, bulking agents.

A vial can be 99% pure and still be 70–85% peptide by mass. The HPLC detector simply cannot see the mannitol. Ask for both numbers.

The chromatogram is the evidence

A purity percentage with no chromatogram cannot be checked by anybody. And when you do get the trace, look at it: real analysis has baseline noise, and real purity drifts between batches. A catalogue where every product is exactly 99.9%, with flawless symmetric peaks, is describing a marketing decision.

Purity says nothing about identity

HPLC tells you how much of the sample is one substance. It does not tell you that the substance is the peptide you ordered. Only mass spectrometry, comparing observed mass to theoretical mass, confirms identity.

And nothing about what else is in there

Heavy metals and bacterial endotoxin are invisible to purity testing and are measured by separate methods. For anything injected, they matter as much as the purity figure everyone quotes.

Red flags

Buyers are rarely fooled by chemistry.

They are fooled by presentation. These are the recurring tells:

A certificate that is “available on request” — and arrives only after payment, if at all.
Identical, near-perfect purity on every product in the catalogue.
A purity number with no chromatogram, or a chromatogram with no baseline noise.
A lot number on the certificate that does not match the vial.
Crypto or cash-app payment only, with no chargeback recourse.
No registered entity, no address, no phone — a contact form and a promise.
A brand-new domain wearing the branding of a vendor that recently disappeared.
Human dosing guidance printed beside a “not for human consumption” disclaimer.

Verify it yourself

Don’t take anyone’s word. Including ours.

Every claim a seller makes about approval status, licensure, or labelling can be checked against a primary source, for free, in about two minutes.

Drugs@FDA — check whether a drug is FDA-approved and find its NDC
DailyMed — read the official FDA label for an approved drug
FDA BeSafeRx — locate a state-licensed online pharmacy
FDA BeSafeRx — how to tell a safe online pharmacy from an illegal one
FDA MedWatch — report a harmful or suspect product

To check a certificate of analysis, enter the report number and case-sensitive verification key printed on it into the issuing laboratory’s own public portal. If the credentials return no record, the certificate is fabricated.

Frequently asked questions

How do I know if a peptide vendor is legit?

Start with the channel, not the vendor. An FDA-approved drug prescribed to you and dispensed by a state-licensed pharmacy sits inside a regulated supply chain; a "research use only" supplier sits entirely outside it. Within the grey market, the signals that best predict quality are a batch-specific certificate of analysis from a named independent laboratory, an actual HPLC chromatogram rather than a bare purity number, mass-spectrometry identity confirmation, and a payment method that gives you recourse.

What is a certificate of analysis (COA) for a peptide?

A COA is a laboratory report describing a specific batch. A useful one names the peptide, the lot number, the testing laboratory and its methods, the HPLC purity with its chromatogram, mass-spectrometry data confirming identity, the net peptide content and salt form, and the date of analysis. A COA that lacks the lot number, the lab name, or the chromatogram cannot be independently checked by anyone.

What is the difference between third-party and in-house peptide testing?

A third-party COA is issued by an independent laboratory that has no commercial interest in the result. An in-house COA is produced by the seller’s own laboratory. Both can be accurate, but only the third-party report is independent verification. If a vendor will not name the laboratory that performed the analysis, treat the certificate as a self-report.

Does 99% purity mean a peptide is safe?

No. Purity is a measure of the peptide relative to peptide-related impurities from synthesis — it says nothing about sterility, heavy metals, bacterial endotoxin, or whether the substance is even the peptide you ordered. Identity requires mass spectrometry; contamination requires separate tests. A perfectly pure, correctly identified peptide can still be non-sterile.

What is net peptide content, and why does it differ from purity?

Purity compares the peptide to other peptide-like impurities. Net peptide content compares the peptide to everything else in the vial: water, counter-ions, salts, and bulking agents. The two are routinely confused. A vial can be 99% pure by HPLC and still be only 70–85% peptide by mass, because the HPLC detector does not register the salts and mannitol that make up the difference.

How do I verify that a peptide COA is real?

Independent laboratories publish their results in a public database, keyed to an identifier printed on the certificate — typically a report or task number together with a case-sensitive unique key. Enter those credentials on the laboratory’s own portal. If they return no record, the certificate is fabricated. Also confirm that the lot number on the certificate matches the lot printed on your vial.

Are compounded GLP-1 drugs like semaglutide safe?

Compounded drugs are not FDA-approved, which means FDA has not reviewed them for safety, effectiveness, or manufacturing quality before they are marketed. FDA has documented fraudulent compounded semaglutide and tirzepatide bearing the names of compounding pharmacies that do not exist, unapproved salt forms such as semaglutide sodium and acetate, active ingredients from facilities it has never inspected, and hundreds of adverse event reports — many involving dosing errors from multi-dose vials. Legitimate compounding has real clinical uses, but it is a meaningfully different risk category from an approved product.

Is it safe to use a peptide labelled "research use only"?

A "not for human consumption" label means no regulator has reviewed the product for human use and the seller is not claiming it is fit for it. Nothing about the labelling guarantees identity, dose accuracy, sterility, or freedom from contaminants. Diligence — an independent batch certificate, verifiable testing, a source you can hold accountable — reduces the risk of the obvious failures. It cannot make an unreviewed product equivalent to a reviewed one.

Sources

U.S. Food and Drug Administration — FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss
U.S. Food and Drug Administration — FDA warns consumers not to use counterfeit Ozempic (semaglutide) found in U.S. drug supply chain
U.S. Food and Drug Administration — Counterfeit Medicine
U.S. Food and Drug Administration — Compounding and the FDA: Questions and Answers
U.S. Food and Drug Administration — Human Drug Compounding: Laws and Policies (503A and 503B)

Educational reference only. Pepperz does not provide medical advice, diagnosis, treatment, prescribing guidance, or dosing recommendations, and does not test, rank, endorse, or sell any product or vendor.