TL;DR: The research peptide vendor landscape changed dramatically between mid-2025 and early 2026. Four major vendors closed — Amino Asylum, Paradigm Peptides, Science.bio, and Peptide Sciences. The vendors still operating are the ones that built real quality infrastructure before the regulatory wave hit. This guide covers what changed, what to look for in 2026, and which vendors meet the bar.

What Changed in 2025–2026

The research peptide market spent several years operating in a low-enforcement environment. Vendors could sell products with minimal testing, vague sourcing, and implied human-use positioning without facing significant regulatory consequences. That changed in 2025.

The sequence of closures:

• June 2025: Amino Asylum — FDA enforcement action over human-use marketing and labeling violations
• December 2025: Paradigm Peptides — criminal guilty plea related to distribution of unapproved drug products
• January 2026: Science.bio — operations ceased; no official statement
• March 2026: Peptide Sciences — operations ceased after 10+ years as the largest US research peptide vendor

Each closure had different proximate causes, but the common thread was operating in ways that attracted sustained regulatory attention — whether through human-use marketing, inadequate quality documentation, or both.

The vendors still operating in mid-2026 are almost uniformly the ones that had invested years earlier in third-party testing, batch-level COA publication, strict “research use only” positioning, and verifiable US operations. The market has been stress-tested, and the survivors are not survivors by accident.

What to Look for in a 2026 Peptide Vendor

The checklist hasn’t changed — the enforcement environment just made it more consequential:

1. Batch-specific COA from an independent lab. Not “available on request.” Visible and downloadable on the product page, with the lab name, test date, batch number, and all results shown. Recognized labs: Janoshik Analytical, Colmaric Analitika, Auriga Research.
2. LCMS identity confirmation plus HPLC purity. The COA must confirm what the molecule is, not just how much of it there is.
3. Strict “research use only” positioning. Any vendor that implies, winks at, or fails to prominently disclaim human use is running a regulatory risk that will eventually affect your supply chain.
4. Verifiable US address. Not just “Made in USA” copy. A real address that you can look up.
5. Responsive support. Email them before ordering. The response time and quality predict everything about how problems get handled.

Bonus criteria that separate the top tier from the merely adequate:

• Endotoxin testing (LAL, USP <85>)
• Sterility testing (USP <71>)
• Heavy metals testing (ICP-MS, USP <232>)
• Residual solvent testing (GC, ICH Q3C)

Vendors Still Operating in Mid-2026

These vendors all meet the four baseline criteria above. Listed alphabetically; not ranked. Selection, pricing, and shipping vary — the right choice depends on the specific peptide you need and your budget.

Ascension Peptides

US-based, testing through Janoshik Analytical. Every product page links to the current batch COA. Catalog focuses on GLP-1s and longevity peptides. 2–4 day US shipping. Mid-tier pricing. Strong transparent testing methodology page.

Core Peptides

One of the most consistently recommended vendors across 2025–2026 comparison articles. Tests through Janoshik and Colmaric. Wide catalog. 2–4 day US shipping. Mid-tier pricing. Has maintained operations continuously through the enforcement wave.

Felix Chemical Supply

Frequently cited as the best budget option that still maintains real quality standards. Unusually thorough testing panel for a budget-tier vendor — includes endotoxin and sterility alongside identity and purity. Narrower catalog. Good for researchers who need the deepest testing at the lowest price point.

Limitless Biotech (formerly Limitless Life Nootropics)

Rebranded in late 2025. Broad catalog including peptides, SARMs, and nootropics. Independent COA per batch. Loyal customer base. Good option for researchers who need a wide range of research compounds from one vendor.

Life Link Research (us)

We synthesize from a US-based facility and run a 6-panel test on every batch: identity (LCMS), purity (HPLC), residual solvents (GC), heavy metals (ICP-MS), endotoxin (LAL), and sterility (USP <71>) — all at Janoshik Analytical. Every COA is published in our public COA library before the batch ships. Medium-wide catalog, mid-tier pricing, 2–4 day US shipping. Full testing methodology here.

Verified Peptides

Differentiates on educational content and testing transparency. Detailed explainers on quality evaluation. Good for researchers who want to understand what they’re ordering, not just receive a number on a page.

Vendor Comparison Table

Vendor	Independent lab	COA per batch	US-based	Endotoxin tested	Sterility tested	Pricing
Ascension Peptides	Janoshik	Yes	Yes	No	No	Mid
Core Peptides	Janoshik, Colmaric	Yes	Yes	No	No	Mid
Felix Chemical	Independent	Yes	Yes	Yes	Yes	Budget
Limitless Biotech	Independent	Yes	Yes	No	No	Mid
Life Link Research	Janoshik	Yes	Yes	Yes	Yes	Mid
Verified Peptides	Independent	Yes	Yes	No	No	Mid

Data reflects publicly available information as of May 2026. Testing policies change — verify current documentation before ordering.

Frequently Asked Questions

Q: Is it safe to order from vendors that weren’t in this list before?
A: Apply the checklist. If a vendor has a batch-specific COA from an independent lab, a verifiable US address, strict research-use positioning, and responsive support, they meet the baseline. New vendors can meet the standard too — but they should meet it, not just claim to.

Q: What happened to Peptide Sciences’ inventory after they closed?
A: Unknown. There have been reports of third parties claiming to sell “former Peptide Sciences” stock, but there is no way to verify the provenance, storage conditions, or current purity of such inventory. We would not recommend purchasing peptides from any source claiming to liquidate a closed vendor’s stock unless a current, fresh COA from an independent lab accompanies each batch.

Q: Will more vendors close in 2026?
A: Possibly. The FDA enforcement framework for research chemicals has not relaxed. Any vendor still engaged in human-use marketing, operating without third-party testing, or without a verifiable US location remains at elevated risk. The survivors are the ones who built the right infrastructure before the pressure arrived.

Q: What’s the most important thing to check when switching vendors?
A: The COA. Specifically: is it from a lab that doesn’t sell peptides, does it show the observed mass vs. theoretical mass on LCMS, and does it show the HPLC chromatogram (not just the number)? If all three answers are yes, you are working with a vendor doing real quality documentation. If any answer is no, ask why before ordering.

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Disclaimer: This article is for informational purposes. All products discussed are intended strictly for laboratory research use and are not for human or veterinary consumption. Vendor information reflects publicly available data as of May 2026 and may have changed. Always verify current vendor status before ordering.

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