Who Are the Biggest US Peptide Sellers? 100 Ranked by Lab Reports and Search

The 10 biggest US peptide vendors

We scored each qualifying seller half on a year of lab reports and half on how visible it is in search, and these ten came out on top. “Biggest” is our word for that mix. Nobody publishes peptide sales figures, so we can’t rank on revenue.

Together the full 100 account for 18,612 published reports in the past year. That’s about a fifth of the 98,700 reports we collected over the same 12 months. Another 20,379 aren’t linked to any seller in our records, so the real share could be higher.

What the ranking hides is the more useful part. Most of those reports were ordered under the sellers’ own names, some are copies of a single test, and several well-known brands barely appear in lab records. All 100 are further down, each linked to its seller page.

How we scored “biggest”

Two measures, weighted equally:

• Lab reports. Published reports in our corpus dated October 30, 2025 to October 30, 2026, counted across every name we’ve merged into one seller.
• Search visibility. US monthly searches for the seller’s name (Semrush, October 5, 2026), plus three public rankings of how well-linked its website is: Common Crawl’s link graph (published October 22, 2026), the Majestic Million and the Tranco list.

Each seller gets a percentile on both, and the score is the average. Anyone in the top 10 on either measure stays in the 100, so a heavily tested seller nobody searches for (or the reverse) isn’t squeezed out. These are the raw inputs for the number one seller:

Semrush US, Oct 5 2026     "simple peptide"     22,200 searches/month
Common Crawl domain graph  com.simplepeptide    link rank 2,488,346
Majestic Million           simplepeptide.com    277 referring subnets
Tranco, list PYK6J         simplepeptide.com    rank 415,022
TitrateLab corpus          Simple Peptide       466 reports in 12 months

We started with 268 candidates: every seller identity in our corpus with at least 75 reports (or 60 in the past year), plus 22 names that only showed up in search data and five client names that appear on many Freedom certificates but aren’t linked to a seller in our records. We dropped 63 of them. Some were closed, some were overseas suppliers or clinics, and for some we couldn’t establish a US storefront or US shipping. That left 205, and these are the top 100. The method section has the details.

Most of these reports were ordered by the sellers

84.3% of the 100’s reports (15,681 of 18,612) are Freedom Diagnostics certificates ordered under the seller’s own name. A Freedom certificate names whoever ordered the test, so the seller, or a supplier ordering in its name, picked the vial. Nothing wrong with that; it’s how most seller certificates work. But it means a big report count mostly tells you the seller’s side tests often, not that anyone else has checked its stock.

Only 569 reports (3.1%) came from vials somebody else picked: 523 mailed in by customers through Finnrick’s testing program, and 46 that Finnrick bought itself. 68 of the 100 sellers had no customer-sent test at all in the past year. Our domestic peptide safety analysis covers why that matters, across 2,500 sellers.

Customer-sent vials failed more often

Split the same 100 sellers’ results from the same 12 months by who picked the vial, and the failures move:

For the seller row we read the first page of the 10,300 certificates we hold as PDFs and compared the product printed on each one with what the lab actually identified. We counted a failure when the lab printed a failed identity verdict, found nothing, or identified a different peptide from the one printed as the product. A few certificates use house codes like “GLP-1R” or “ULTRA-RT” that we couldn’t match to a compound, and we left those out rather than guess. One we couldn’t call either way: an Ion Peptide certificate printed “Selank (N-Acetyl)” as the product and identified N-acetyl Semax amidate, but the lab marked identity as confirmed, so we didn’t count it.

Don’t read this as “customer-sent tests show the true failure rate.” People who send a vial in may already be suspicious of it, Finnrick’s labs and methods differ from Freedom’s (labs can disagree even on the same batch, as Janoshik and Chromate did), and 520 tests spread over 32 sellers is thin. Still, the gap is about 35 times, and it points the same way as our earlier domestic analysis.

A case where both tests agree: Nexaph’s tesamorelin

Nexaph is number two on the list. In March 2026 a customer mailed Finnrick a vial they identified as Nexaph tesamorelin, batch TES1003052026-18. The vial itself had no label, but the batch number follows the format on Nexaph’s own certificates. Finnrick’s lab found no tesamorelin. Its infrared scan matched TB-500.

Nexaph’s own Freedom certificate for a sibling lot, TES1003052026-20, says the same thing. The product line reads “Tesamorelin 10mg”. The lab’s mass identification reads Thymosin Beta-4, which is the name Freedom uses when it identifies TB-500.

Two labs, two vials from neighboring lots, and the same identification. We can’t tell from the records whether this was a labeling slip at the supplier or something else, and lots -18 and -20 aren’t necessarily the same production run. What it does show is that a certificate can be public and still describe a different peptide than the label. Read the identification line, not just the purity number. Our COA reading guide walks through where to look.

The other four clear failures on sellers’ own certificates were Peptide Restore (a “TB-500” vial identified as thymosin alpha-1), JT’s Biocore (a “GLOW” blend in which the lab found tirzepatide instead of TB-500), and Como Peptides and Novaglo Research (nothing detected).

One test, three certificates

These three Freedom Diagnostics certificates were issued on the same day:

Same lot, same measured amount and same purity to three decimal places, issued with consecutive numbers to three clients: “Wholesale”, Simple Peptide and Alpha & Omega. That looks like one test issued three times, which is how a supplier would share one result with the stores it sells through. Plenty of US stores resell vials made by someone else under their own label (what a domestic reseller is), and this is what that looks like on paper. It also tells you the certificates of those two stores, ranked first and eighth, cover the same lot of retatrutide. It doesn’t tell you who owns them.

It isn’t a one-off. Of 11,900 seller-ordered certificates from the top 100 that list a lot and purity, 1,260 (10.6%) match a certificate issued to a different seller or client on lot, purity, date, compound and measured amount. For two sellers it’s nearly everything:

• Simple Peptide: 378 of 397 such certificates are shared.
• Alpha & Omega: 369 of 390.

So we reran the ranking with each shared certificate split between its clients. Nexaph moves to first, Simple Peptide drops to seventh and Alpha & Omega to 13th. The same 100 sellers make the list either way. We kept the main ranking on plain report counts, because a shared certificate still covers that seller’s stock. But if you’re judging how much testing is unique to one seller, the split count is the fairer number.

A footnote that makes it messier: in May 2026 a customer mailed Finnrick a vial they said was Simple Peptide retatrutide from that same lot, GR24-12222025-J. In July, Finnrick reported no retatrutide. The vial had no label, though, and the customer reported 15 mg where the lot is a 24 mg product. So that record can’t settle anything about the certified lot. We’re showing it because it’s the kind of thing that only turns up when someone outside the seller checks.

If you’ve got a batch number from your own vial, Batch Finder will show you whether someone already paid to test it. If nobody has, here’s how to get a vial tested yourself.

Searched a lot, tested a little

Testing volume and search demand barely line up. Five of the ten sellers with the most search visibility had fewer than 50 reports in our records over the past year:

• Core Peptides: 9,900 searches a month, 46 reports.
• Swiss Chems: 9,900 searches, 44 reports.
• Peptide Crafters: 14,800 searches, 48 reports.
• Limitless Life Nootropics: 4,400 searches, 1 report (23 all-time).
• Biotech Peptides: 8,100 searches, no reports we could attribute.

Low counts here don’t mean these sellers never test. They may publish certificates we haven’t collected, or test at labs we don’t track. But the customer-sent records we do have aren’t reassuring: two of Core Peptides’ customer-sent vials, a retatrutide in August and a tirzepatide in September 2026, came back without the peptide the sender named.

Then there’s the opposite case. Peptaris has more reports than anyone, 1,432 in a year, and about 30 searches a month. The certificate below names it as the client and shows plain vials with a batch sticker.

A store using the Peptaris name was live when we checked, but nothing on it links it to the business on those certificates, so its website’s link rankings got no weight and only its 30 brand searches count. That’s why the seller with the most reports sits at 53rd. Huge testing volume with almost no brand searches looks more like a wholesaler supplying other stores than a shop most buyers deal with directly. That’s an inference, not something we’ve confirmed.

A third of the stores want an account first

We loaded every seller’s homepage once on October 30, 2026, in a headless Chrome browser set up like a normal desktop visitor with no account, and looked at what came up. Leaving out the five stores we couldn’t tie to their sellers and Planet Peptide, whose terms forbid automated access, that’s 94 stores:

• 32 wanted an account before showing products or prices.
• 18 blocked our browser or showed a “confirm you are human” check.
• 30 showed a 21+ or research-use prompt first.
• 14 were open.

Login walls aren’t automatically shady. Some sellers say regulations made them do it; NG Syndicate’s page cites “updated industry regulations”. But they do mean you often can’t compare prices, check a batch or read a certificate before handing over your email. A real person would get past most of the “human” checks that stopped our browser, so treat that number as a ceiling.

The 10th seller closed, and warned about fakes

Our first draft of this list had Soma Chems at number 10. When we loaded its site to take the screenshots above, this is what came up:

It’s closed, and it says copycat sites are already using its name. It joins a long list of shut-down peptide sellers. That fits what we found while building the list: lookalike domains are common in this market. We found suspected copies of several big names, including Verified Peptides (four lookalike stores), Biotech Peptides and Simple Peptide. Apex Peptides, at 93rd, is a different problem. Its reports come under several “Apex” names, and the domain linked to it now shows a temporarily closed skincare shop, so we couldn’t confirm which store is which.

The full list

98 of the names link to that seller's TitrateLab page, where you can see its report history. Notes flag shared certificates and identity failures from the past year. "Store unconfirmed" means we couldn't tie a storefront to the seller with confidence, so its website's link rankings got no weight. You can also download the table as a CSV.

US status, briefly: 55 of the 100 say they ship from the US. 36 show it indirectly (a US address, phone number, LLC or dollar pricing). Four also ship abroad, and two of those, Peptide Gurus and Barn, say they have overseas warehouses. Three are US only by the pattern of US labs they use. Two, Peptaris and Genpeptide, rest on our own earlier review. For the overseas side of the market, see the international supplier directory. Our domestic reseller rankings rank the same market on all-time unique lab reports alone, with test results for each seller; this list adds search demand and the past year only, so the order differs.

What this ranking can’t tell you

• It’s not a sales ranking. Lab reports and search demand stand in for size. A seller that tests rarely, or sells mostly through private groups, can be bigger than it looks here.
• It’s not a quality ranking. A high spot means more testing and more visibility, nothing more. Check the specific batch.
• Report counts lean on one lab. Freedom Diagnostics certificates are 84% of the total, and sellers decide what to send it.
• Customer-sent testing is thin. 520 customer-sent results across 32 sellers can flag problems. It can’t give a reliable failure rate for any one seller.
• The search data is a snapshot. Brand volumes come from Semrush on October 5, 2026; 12 of the 100 had no volume we could use. A generic name like “real peptides” or a shared one like “apex peptides” can’t be credited to one store, so we left it out.
• Identities are hard. Five storefronts couldn’t be tied to their sellers. Merged names can hide two businesses (Apex), and one test can sit under several names (Simple Peptide and Alpha & Omega).
• Stores change fast. Soma Chems closed this month. Anything about a storefront is as of October 30, 2026.

Method and sources

Candidates. We took every seller identity in our corpus with at least 75 published reports, or 60 in the past 12 months, and added 22 sellers that showed up only in search data. We merged known aliases into one seller. We removed sellers marked as overseas in our review, Chinese manufacturers, clinics, group buys, closed stores and anything without US evidence. That left 205 of 268. Closed is judged on the storefront as of October 30, 2026.

Lab pillar. Published reports dated October 30, 2025 to October 30, 2026 (test date, or discovery date where there’s no test date). Who picked the vial comes from the source. A Freedom Diagnostics certificate names the client who ordered it, and Finnrick records say whether a customer, Finnrick or the seller sent the sample.

Identity checks. For seller certificates we extracted the printed product, the lab’s identification and any printed identity verdict from 10,300 stored Freedom Diagnostics PDFs, mapped both names to compounds, and reviewed every flag by hand. 7,083 could be compared. We counted 5 clear failures: a failed verdict, nothing detected, or a different peptide identified. For Finnrick records, “identity fail” is Finnrick’s own verdict that the sample isn’t the labeled substance; for an unlabeled vial, that’s the substance the sender named.

Shared certificates. Two certificates are “shared” when they have the same lab, lot, purity, report date, compound and measured amount under different sellers or client names. A seller’s own alternate spellings count as one. For the sensitivity ranking, each one counts as one divided by the number of clients.

Search pillar. US monthly brand searches from Semrush (October 5, 2026), weighted 40%; Common Crawl harmonic-centrality rank (cc-main-2026-aug-sep-oct), 25%; Majestic Million referring subnets (October 30), 20%; Tranco rank (list PYK6J, October 30), 15%. If a seller has no brand volume, the other weights scale up. The website-based measures only count when we matched the storefront with medium or high confidence.

Score. The average of the lab and search percentiles. Anyone in the top 10 of either is kept. That rule changed only two places: it keeps Limitless Life Nootropics and Biotech Peptides, which would otherwise rank 103rd and 105th.

Storefronts. One homepage load per seller in headless Chromium on October 30, 2026, with a screenshot that we reviewed by eye. We didn’t create accounts or click through age prompts.

Sources. The original certificates and Finnrick records are linked beside each figure above. The public table is in the CSV. The underlying record-level corpus stays private, so the counts can’t be re-derived from public data alone.

Prepared by the TitrateLab Research Desk with AI-assisted data analysis and editorial tooling; reviewed October 30, 2026. TitrateLab collected these reports and did not perform the assays. Spotted a mistake, or run one of these stores and want to point us to records we missed? Tell us.

Open original ×