Almost every research peptide vendor advertises the same three things: 99% purity, third-party testing, and a COA with every batch. Those claims are trivially easy to print and surprisingly hard to confirm. This guide is the checklist we use — seven checkable criteria that separate documentation from decoration — followed by five vendors whose claims we could not independently verify.
Why this matters right now
At least nine notable research peptide vendors closed between mid-2025 and mid-2026 — among them Peptide Sciences, Amino Asylum, Paradigm Peptides and Science.bio — as FDA enforcement escalated and Eli Lilly and Novo Nordisk pursued litigation against GLP-1 suppliers. Buyers are being pushed toward unfamiliar vendors faster than those vendors can build a track record.
Each criterion below is something you can check yourself in a few minutes, without taking anyone's word for it.
A rating printed on a vendor's own homepage is marketing, not evidence. Look for a third-party platform you can open yourself (Trustpilot, Google Reviews) where you can read individual reviews, see the date range, and check whether complaints get answered. A vendor claiming thousands of reviews with no independent page to back it is the single most common red flag in this industry.
Can you find the review page without the vendor linking you to it?
Nearly every vendor says 'third-party tested.' Far fewer will tell you which lab. A named lab (for example, Sports Technology Labs publishes COAs from MZ Biolabs) can be looked up and held accountable. 'Third-party tested' with no lab name is an unfalsifiable claim.
Is the laboratory named, and can you look it up?
A Certificate of Analysis is only meaningful if it corresponds to the lot you received. A single generic COA posted for a product line tells you nothing about your vial. Look for batch numbers on both the COA and the label, with recent issue dates.
Does the COA carry a batch number that matches your product?
ISO/IEC 17025 is the international standard for testing laboratory competence. When a vendor cites it (Licensed Peptides, for instance, states its batch testing runs through an ISO/IEC 17025:2017 accredited lab), that is a checkable, specific claim. Vague phrases like 'lab grade' or 'pharmaceutical grade' are not standards — they are adjectives.
Is a real standard cited, or just impressive-sounding language?
HPLC measures purity — how much of the sample is the intended compound. Mass spectrometry confirms identity — that the compound is actually what the label says. Purity testing alone cannot tell you the vial contains the right peptide. Serious vendors run both.
Do the COAs show identity testing, not just purity?
How long has the vendor operated under this name, and is it clear who you are buying from? Watch for near-identical sibling storefronts sharing a catalog, or brand names that collide with unrelated companies. Ambiguity about who you are transacting with is a risk in itself, particularly when it comes to refunds.
Is there one clear company, one clear address, one clear brand?
This industry contracts hard. At least nine notable vendors closed between mid-2025 and mid-2026 — including Peptide Sciences, Amino Asylum, Paradigm Peptides and Science.bio — as FDA enforcement escalated and Eli Lilly and Novo Nordisk pursued suits against GLP-1 suppliers. The vendors worth trusting handle it responsibly: Science.bio fulfilled outstanding orders or refunded them before closing. Others simply went dark.
If they shut down tomorrow, would you get your money back?
It is easier to recognise a weak claim once you have seen a strong one. These four vendors publish information you can independently confirm — which is the point. We hold affiliate relationships with Purgo Labs, Amino Club and Licensed Peptides, and none with Sports Technology Labs; the criteria are applied identically either way, which is why a vendor we earn nothing from sits on this list above ones we do.
4.8 TrustScore across 101 reviews on Trustpilot (read 10 October 2026), batch-specific COAs published on every product page, HPLC and mass spectrometry testing, US-based fulfillment from Scottsdale, Arizona, same-day dispatch on weekday orders before 2PM EST.
Roughly 4.6 on Trustpilot across 100+ reviews, testing attributed to a named third-party laboratory (ILS Labs) with seven or more tests per compound, and batch-specific COAs published on each product page — ungated, meaning pricing and certificates are viewable without an account. A minority of recent reviewers report shipping delays, which the company has publicly acknowledged.
Roughly 4.8 on Trustpilot across several hundred reviews, batch testing through an ISO/IEC 17025:2017 accredited laboratory, endotoxin screening and sterility checks. Recurring criticisms in those reviews cite slow shipping, customer service responsiveness, and premium pricing.
Operating since 2018, COAs from a named third-party laboratory (MZ Biolabs) posted per product with batch numbers, HPLC and mass spectrometry results, endotoxin and heavy-metal screening on select products.
If you would rather skip the research
Purgo Labs is the vendor we point researchers to, because it clears every criterion above without requiring you to take anything on faith: an independently viewable Trustpilot history, batch-specific COAs published on each product page, HPLC and mass spectrometry testing, and US-based fulfillment. Use code HEALTH for 20% off.
Shop Purgo Labs — Code HEALTH for 20% OffRead this first. Everything below describes what we could and could not confirm from independent sources as of July 2026. It is not an allegation of wrongdoing against any company listed. A vendor with little independent history is unproven, not dishonest — and several of these may turn out to be excellent. The practical consequence is simply this: where independent verification does not exist, you are relying entirely on the vendor's own description of itself. We will update this page as evidence appears.
What the vendor claims
≥99% purity verified by HPLC and mass spectrometry, every lot tested for identity and purity before shipping, a COA-before-purchase policy, same-day shipping on orders by 2PM EST, and free shipping over $300.
What we could confirm
The site is live and the claims are specific and well presented. The COA-before-purchase policy, if honored, is a genuinely strong practice.
What we could not verify
What the vendor claims
US-based supplier of lyophilized chemical reference materials for in-vitro research, ≥99% HPLC purity, third-party COAs, and ISO-compliant manufacturing.
What we could confirm
The site is live, professionally built, and publishes a research/education section. Reviews that do exist are positive.
What we could not verify
What the vendor claims
No substantive vendor documentation surfaced in our research.
What we could confirm
Nothing we could independently confirm.
What we could not verify
What the vendor claims
No substantive vendor documentation surfaced in our research.
What we could confirm
Nothing we could independently confirm.
What we could not verify
What the vendor claims
No substantive vendor documentation surfaced in our research.
What we could confirm
Nothing we could independently confirm.
What we could not verify
Open Trustpilot or Google directly and search the exact domain. If the only positive coverage is on the vendor's own site or on pages that link to it, treat the rating as unverified.
Email support and ask which laboratory performs their testing and whether it is accredited. A confident vendor answers immediately. A vague answer is itself an answer.
When your order arrives, compare the batch number on the vial to the COA. If they do not match — or there is no batch number — the documentation does not cover what you received.
Purgo Labs publishes batch-specific COAs on every product page, tests by HPLC and mass spectrometry, ships from the United States, and has an independently viewable review history. Use code HEALTH for 20% off your order.
Shop Purgo Labs — Code HEALTH for 20% OffAffiliate disclosure: we earn a commission on purchases made through this link. Research use only.
No, and we want to be explicit about that. Everything on this page is a statement about what independent evidence we could and could not find — not an accusation of wrongdoing. A new vendor with almost no review history is unproven, not dishonest. The practical point is different: when independent verification is unavailable, you are relying entirely on the vendor's own word, and you should price that risk accordingly.
Try to reach the review page without using the vendor's link. Open Trustpilot or Google directly and search the domain. If a vendor advertises thousands of reviews but no independent page exists, the number is unverifiable. Also check whether you can read individual reviews with dates and whether the company responds to complaints — aggregate scores with no readable reviews behind them mean little.
'Third-party tested' is a claim anyone can print. A named laboratory is a checkable fact — you can look the lab up, confirm it exists, and see whether it holds accreditation such as ISO/IEC 17025. If a vendor will not say which lab tested the product, there is no way to confirm the testing happened at all.
A Certificate of Analysis describes one specific production lot. If the COA has no batch number, or the batch number does not match the vial you received, the document tells you nothing about your material. Batch-specific COAs are the difference between documentation and decoration.
Purgo Labs is our first recommendation: independently viewable Trustpilot history (4.8 across 101 reviews, 10 October 2026), batch-specific COAs published on every product page, HPLC plus mass spectrometry testing, US-based fulfillment with same-day dispatch, and the deepest GLP-1 and longevity catalog we cover. Amino Club is our second choice — it names its testing laboratory (ILS Labs, seven-plus tests per compound) and publishes ungated batch-specific COAs, though with a narrower GLP-1 selection. Licensed Peptides and Sports Technology Labs also clear most of the checklist and are covered in our comparison guides. Disclosure: we earn a commission on purchases through Purgo Labs, Amino Club and Licensed Peptides links, and nothing from Sports Technology Labs.
At least nine notable vendors closed between mid-2025 and mid-2026, including Peptide Sciences, Amino Asylum, Paradigm Peptides and Science.bio. Three forces converged: FDA enforcement escalated from warning letters to raids and prosecutions, Eli Lilly and Novo Nordisk filed suits against GLP-1 suppliers, and several quality failures damaged reputations. This is why criterion seven — how a vendor behaves under pressure — matters as much as purity testing.