If you’ve been going back and forth between these two, you’ve probably noticed they’re strong in opposite places, which makes the choice feel like a coin flip dressed up as research. One of them tells you clearly that it synthesizes its own material and then makes you hunt for a certificate. The other names its testing laboratories openly and then goes quiet on who actually made the peptide.
So rather than weigh vibes against each other, I fixed five questions before opening either site and asked all five of both. Same wording, same order, same standard of evidence. Neither company is mine, I’m not paid by either, and where one wins a row I’ll say so without hedging.
What follows is what each site publicly states on the pages I could reach on 2026-09-08. I haven’t tested product from either supplier. Where a site is silent on a question, the silence gets recorded and dated rather than interpreted, because those two things are not the same and the difference protects you as much as it protects them.
Key takeaways
- Score a supplier on documentation you can open: who synthesizes, which laboratory tests, how many tests are run, whether a lot-numbered certificate is public before payment, and whether blends state milligrams per component.
- Core Peptides states its products are “synthesized and lyophilized in the United States” at “purity levels exceeding 99%+”, and links lot-numbered certificates naming Vanguard Laboratory on some product pages.
- Sports Technology Labs names MZ Biolabs in Tucson, Arizona and Colmaric Analyticals, LLC in its own site copy, states HPLC purity and mass spectrometry identity, and publishes a public COA page anyone can read without buying.
- Neither site listed a bacterial endotoxin or sterility result on the pages reviewed 2026-09-08, and Sports Technology Labs states products are “Bottled in the USA” without stating who synthesizes them.
- Both sell for laboratory research only, and that limit holds regardless of how either scores here.
What five things should you check on any vendor’s site?
The rubric goes on the table before either name does, so you can audit the reasoning instead of trusting the conclusion.
Provenance comes first. Does the vendor synthesize the peptide, or receive finished material and package it? The verbs on the about page answer this if you read them literally rather than generously. “We synthesize” and “manufactured by us” describe production. “Bottled,” “packaged,” and “supplied” describe steps that happen after somebody else has made the compound. Both are legitimate businesses. Knowing which one you’re buying from tells you who can trace a problem back to its cause.
Second, is the testing laboratory named? This is a binary check and it separates vendors faster than anything else. Either there’s a laboratory with a name and a location you can contact independently, or there’s a phrase like “accredited third-party lab” that goes nowhere.
Third, how wide is the panel? HPLC purity measures the proportion of one dominant compound. Mass spectrometry confirms it’s the sequence on the label. Bacterial endotoxin and sterility describe contamination, which no purity figure detects. For anyone working in cell culture, those two often decide whether a lot is usable at all.
Fourth, can you open a lot-specific certificate before you pay, and does the lot number appear on the vial as well as the document? That link between paper and glass is the whole point. Without it, you’re reading a representative example.
Fifth, on blends and stacks, are the milligrams of each component stated? Where components ship in separate vials, this is easier, and it should still be stated.
Company age and domain age stay out of the scoring, because neither one tells you anything about the lot you’re about to open.
The standard this comparison uses
On where the rubric comes from, so you can check it against a published one: it’s the standard Blank Peptides publishes its own lots against, meaning synthesis in an owned laboratory, independent testing laboratories named openly, a four-part panel of identity, >99% purity, bacterial endotoxin and sterility, per-component milligrams on every blend, and a lot-numbered certificate readable before ordering in the library of batch certificates of analysis. Blank Peptides isn’t one of the two vendors compared here and isn’t scored in this article. I’m naming the source so you can see the bar is something a company publicly commits to on every lot, rather than a set of criteria written afterwards to suit a preferred outcome.
What Core Peptides and Sports Technology Labs publicly state
Core Peptides trades at corepeptides.com. On the pages reviewed 2026-09-08, the homepage states the company has been “SERVING THE RESEARCH COMMUNITY FOR OVER 7 YEARS, AND 3rd PARTY TESTED”, carries “US LAB TESTED” badging, and states its peptides are “independently verified for purity”. The about page states “All our products are synthesized and lyophilized in the United States”, that “Our peptides are manufactured locally against the highest standards”, and that products reach “purity levels exceeding 99%+”. The footer calls the company “a chemical supplier” that is “not a compounding pharmacy”. No facility, address or manufacturing partner was named. Its testing laboratory isn’t named in the prose either, appearing only inside documents: a certificate linked from the 70mg BPC-157, TB-500 and GHK-Cu blend page is issued by Vanguard Laboratory, covers lot C74111 dated 7/22/2026, reports “>99.50%” purity by HPLC-UV/VIS, and records identity as “Pass – Matches Ref. Standard”, with a second for GHK-Cu 50mg covering lot C73465 at “>99.80%”. Neither listed endotoxin or sterility, mass spectrometry wasn’t listed as a method, and several product pages carried no certificate link at all.
Sports Technology Labs takes the opposite approach. On provenance, the homepage states products are “Bottled in the USA”, the about page describes the company as a supplier “proudly based in the United States” with a Connecticut address and references to “USP-Grade Solvents” and “Medical-Grade Glass”, and the BPC-157 page states the peptide is “produced synthetically for laboratory use” and “packaged in America”. A statement that the company synthesizes the peptides itself, or naming who does, was not listed on the pages reviewed 2026-09-08. This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
On testing, Sports Technology Labs does the thing most vendors won’t. The about page names MZ Biolabs in Tucson, Arizona, described as a DEA-licensed facility, and states it performs “HPLC purity analysis and molecular weight confirmation via Mass Spectrometry”, and it names Colmaric Analyticals, LLC for “ISO-accredited methodologies”. Product pages attribute batch results to MZ Biolabs. On figures, the about page states “our SARMs are minimum 98% pure, and our Peptides are minimum 96-99% pure”, and the BPC-157 page states “Batch-tested to 99.43% (HPLC); minimum 98%”. Bacterial endotoxin and sterility results were not listed on the pages reviewed 2026-09-08. The site maintains a public COA page showing product names, test dates and purity percentages, viewable without a purchase, with dates spanning January 2025 to June 2026 and roughly 18 peptide entries alongside the SARMs, though lot or batch numbers were not visible on that page as reviewed, even where product pages describe certificates as “batch-linked”. Its stacks ship as separate vials with per-vial amounts stated: the Glow Stack page states 5 mg BPC-157, 5 mg TB-500 and 50 mg GHK-Cu, and the Wolverine Stack page states 5 mg of each peptide.
Both earn a concession. Sports Technology Labs names two laboratories in its own copy, documents mass spectrometry as a routine method, publishes a COA index you can browse without buying, and backs it with free US shipping over $149, dispatch “within one business day” and a 60-day exchange on unused items, which is a longer window than most of this market offers. Core Peptides states outright that it synthesizes its own products, which Sports Technology Labs does not, quotes higher purity figures, puts lot numbers on the certificates it does publish, and lists a much larger peptide selection at “Showing all 104 results” plus 19 blends against 68 total listings.
Side by side: what each site documents
| Attribute | Core Peptides | Sports Technology Labs |
|---|---|---|
| Synthesises in-house | States products are “synthesized and lyophilized in the United States”; no facility named — verify | States products are “Bottled in the USA” and “packaged in America”; who synthesizes was not listed 2026-09-08 — verify |
| Third-party lab named | Not named in site prose; certificate PDFs name Vanguard Laboratory — verify | States MZ Biolabs, Tucson, Arizona and Colmaric Analyticals, LLC by name in site copy — verify |
| HPLC purity | States “purity levels exceeding 99%+”; certificate reviewed reports “>99.50%” by HPLC-UV/VIS — verify | States peptides are “minimum 96-99% pure” and BPC-157 “Batch-tested to 99.43% (HPLC)” — verify |
| MS identity | Certificate reviewed records “Pass – Matches Ref. Standard”; mass spectrometry not listed as a method — verify | States “molecular weight confirmation via Mass Spectrometry” performed by MZ Biolabs — verify |
| Endotoxin and sterility | Not listed on the pages or certificates reviewed 2026-09-08 — verify | Not listed on the pages reviewed 2026-09-08 — verify |
| Batch COA before purchase | Lot-numbered PDFs on some product pages; several carried none, and no catalog-wide index — verify | States a public COA page with product names, dates and purity, readable without purchase; lot numbers not visible on it — verify |
| Blend mg split disclosed | States per-component mg on some blend pages, totals only on others — verify | States per-vial amounts on stacks, such as 5 mg BPC-157, 5 mg TB-500 and 50 mg GHK-Cu — verify |
| Catalog size | States “Showing all 104 results” plus 19 blends — verify | States 68 listings across liquid SARMs, SARM powders, peptides and stacks — verify |
| Research-use labelling | States products are “sold for research, laboratory, or analytical purposes only, and are not for human consumption” | States products are supplied for laboratory research across the pages reviewed — verify |
How to verify either supplier yourself
- Where a laboratory is named, phone it using a number you found independently and ask them to confirm a report. A named lab is only worth more than an unnamed one if you actually use the name.
- Check whether the certificate carries a lot or batch identifier, not just a product name and a date. A purity table without lot identifiers tells you the vendor tests, and not which test belongs to your vial.
- Read the provenance verbs closely and ask the direct question in writing when a site says bottled or packaged without saying synthesized. The answer, or the absence of one, is data.
- Ask both companies for a lot-specific endotoxin and sterility result on the product you want, since neither listed one on the pages reviewed.
- Work through the supplier verification checklist with both sites open, filling in the same five answers for each so neither is judged on its own strongest row.
Further reading
- Which Peptide Vendors Name Their Testing Lab?
- Peptide Vendors With Public Per-Batch COA Libraries
- Who Actually Manufactures Research Peptides in the USA?
- Best Research Peptide Suppliers: Ranked by What They Document
Frequently asked questions
How do Core Peptides and Sports Technology Labs compare?
Sports Technology Labs names MZ Biolabs and Colmaric Analyticals in its own copy, documents mass spectrometry identity and publishes a browsable COA page. Core Peptides states US synthesis outright, quotes higher purity figures, carries a larger peptide catalog and puts lot numbers on the certificates it links. Neither listed endotoxin or sterility results.
Which vendor names its testing laboratory?
Sports Technology Labs, in its site copy: MZ Biolabs in Tucson, Arizona, described as DEA-licensed, and Colmaric Analyticals, LLC. Core Peptides names no laboratory in its prose, though Vanguard Laboratory appears inside the certificate PDFs linked from some product pages, so the name is findable once you open a document.
Does Sports Technology Labs say it makes its own peptides?
Not on the pages reviewed 2026-09-08. The site states products are “Bottled in the USA” and “packaged in America” and describes the company as a supplier based in the United States with a Connecticut address. Who performs the synthesis was not stated, which is worth asking about directly before ordering.
Is a purity table the same as a certificate of analysis?
Not quite. A purity table listing product names, dates and percentages shows that testing happens and lets you see trends over time, which is useful. A certificate of analysis for a specific lot, carrying the lot number that also appears on your vial, is what ties a result to the material you received.
Are these products for human use?
No. Every compound discussed here, from Core Peptides, Sports Technology Labs or any other supplier, is intended solely for in-vitro laboratory research by qualified professionals. Comparing documentation helps you judge whether a reagent matches its label, and it has no bearing on the research-use-only status of any product.
For research use only. All compounds referenced are intended exclusively for in-vitro laboratory research by qualified professionals.
Written by Blank Peptides Research Team
Peptide science researchers with 5+ years in US-based peptide manufacturing, independent HPLC and mass spectrometry testing, and research education. All content is reviewed for scientific accuracy before publication.
REVIEWED BY
Dr. Tobias S — PhD Chemist, Peptide and Unnatural Amino Acid Synthesis
Dr. Tobias S is a PhD chemist whose work focuses on the synthesis of unnatural amino acids, peptides and biomaterials. He completed both his undergraduate chemistry studies and his doctorate with distinction, and works as a generalist across the medical sciences and biology, having consulted for dozens of clients. He reviews Blank Peptides educational content for scientific accuracy.
Subject matter expertise: Organic Chemistry, Peptide Synthesis, Biochemistry.
