2026 HEAD-TO-HEAD
DelixLabs vs Core Peptides
An honest comparison of two U.S. research-peptide vendors — purity, COAs, shipping, and what actually matters at the bench.
Quick Verdict
Both vendors run HPLC testing and claim 99%+ purity. The differences come down to COA accessibility, catalog focus, and operational tightness. If you want lot-matched COAs visible on every product page before you check out, plus a Janoshik verification key you can check yourself for every batch, DelixLabs is the better fit. If you need an extremely wide catalog and have time to request COAs on a per-lot basis, Core Peptides remains a legitimate operator.
Shop GLP-RT (from $90) →Side-by-Side Comparison
| Criteria | DelixLabs | Core Peptides |
|---|---|---|
| Purity floor | ≥99% (HPLC) | 99%+ claimed |
| HPLC testing | Yes, third-party | Yes, third-party |
| Independent verification | Janoshik task # + key for every batch, checkable on janoshik.com | Varies by lot |
| COAs on product page | Lot-matched, every product | Available on request |
| Catalog size | Curated, fast-moving | Larger, wider variety |
| Shipping | U.S. domestic, tracked | U.S. domestic |
| Same-day shipping | Orders by 2 PM CT | Check vendor policy |
| Affiliate program | 20% commission, 25% at volume | Check vendor program |
| Refund / replacement on QC failure | Published policy | Case-by-case |
Where DelixLabs Wins
DelixLabs
- COAs are not an afterthought. Every batch is tested by Janoshik, and we publish the task number and verification key so you can pull the original report from janoshik.com yourself. You verify before you buy, not after.
- Tighter catalog means fresher stock. By curating around the most-researched peptides instead of carrying 200+ SKUs, every lot moves quickly. No aged inventory degrading on a shelf.
- Fast, direct support. Emails go straight to the two people who run the company. If a vial arrives off-spec, replacement or refund is policy, not a negotiation.
- Strong affiliate program. 20% commission on every referred order, 25% at consistent volume.
Where Core Peptides Has the Edge
Core Peptides
- Wider catalog. If you need an obscure or niche peptide that does not justify a curated catalog slot, Core probably stocks it.
- Established brand. Years of operating history and a recognizable name in the research community.
- cGMP facility references. Marketing materials reference compliant manufacturing partners, which adds confidence.
- COAs require a request. You have to email or message to confirm a specific lot before purchase — adds friction.
How To Choose Between Them
Pick DelixLabs if: you run repeatable assays where lot-to-lot variance matters, you want COAs visible before checkout, you want to verify every batch on the lab’s own site, or you want a 20% affiliate program.
Pick Core Peptides if: you need an unusual or niche peptide that a curated catalog might not stock, you do not mind requesting COAs separately, and brand familiarity is a factor.
Pricing Reality Check
Both vendors price within typical U.S. research-peptide ranges. DelixLabs prices for the QC we run (third-party Janoshik HPLC testing on every batch, with public verification keys); Core Peptides prices for broader catalog reach. We do not chase the bottom of the market because the bottom of the market is where corner-cutting happens. If the price looks too good for the purity claim, the math does not work and the COA is probably stale.
GLP-RT Starter Kit, $115 (vial + both BAC waters) →Frequently Asked Questions
Is Core Peptides a legitimate vendor?
Yes. Core Peptides is an established U.S. operator with HPLC testing and a real catalog. This comparison is not about legitimacy — both vendors are legit. It is about which one better matches what you need for your specific workflow.
Why does DelixLabs publish COAs on every product page?
Because verifying a lot certificate against the chromatogram before you buy is the only way to know what you are actually getting. Hiding COAs behind a request flow protects no one except a vendor sitting on a bad lot.
How do I know a Janoshik report is real?
Every Janoshik report has a task number and a verification key. Enter the task number and key at janoshik.com/verify and Janoshik confirms the test on its own site. Check that the compound, purity, mass and test date match what the vendor shows you. If a vendor will not give you a key, you are trusting the vendor, not the lab.
Can I use both vendors?
You can — but for any single ongoing assay you should pick one and stay consistent. Mixing vendor lots in the same experiment introduces a variable you cannot control for cleanly.
What is the DelixLabs affiliate rate?
20% commission on every referred order, 25% at consistent volume. Apply at delixlabs.com/affiliate-registration.
Our Honest Recommendation
For most research workflows in 2026, DelixLabs is the stronger choice — not because Core Peptides is bad, but because independently verifiable Janoshik reports on every batch, same-day shipping, and direct founder support remove friction from the parts of the buying experience that actually affect your results. Start with one product, verify the COA, run your assay, decide for yourself.
Start with GLP-RT →Switching from Peptide Sciences? See our guide to the best Peptide Sciences alternatives in 2026.
Last updated: May 2026. Vendor comparison based on publicly available product information, third-party reviews, and stated company policies at time of publication.