Peptide Sciences Shut Down — Here Are the Best Alternatives in 2026

Last updated: June 2026 · Research use only

Short answer: Peptide Sciences shut down in March 2026 and Science.bio closed in January 2026, leaving researchers without two of the field’s most-used suppliers. The best replacements are vendors that publish batch-specific, independent-lab Certificates of Analysis (COAs) and ship domestically from the U.S. — led by Proxiva Labs, which provides a COA with every order, same-day shipping before 4 PM EST, and a 39-compound catalog. The rest of this guide explains how to pick a replacement and compares the top options.

What happened to Peptide Sciences and Science.bio?

Two of the most widely-referenced research-peptide suppliers exited the market within months of each other: Science.bio in January 2026 and Peptide Sciences in March 2026. For researchers, the practical problem isn’t just finding a new source — it’s finding one that matches the documentation standard they relied on, without gambling on an unverified reseller.

The single most important thing when switching: don’t choose a vendor you can’t verify. That means a real, batch-specific COA you can read before you buy.

How to choose a replacement (3 checks)

1. Public, batch-specific COAs. From an independent lab, tied to the batch you’ll receive — not “available on request.”
2. Purity against the bar. ?96% by HPLC is the floor, ?99% is excellent. Look for mass-spec identity confirmation too.
3. Domestic shipping & stability. A U.S. shipping origin, working support, and stable payment processing so your supplier doesn’t become the next shutdown.

Best Peptide Sciences alternatives in 2026

1. Proxiva Labs — best overall replacement

• Verifiable COAs: batch-specific certificates from independent lab Vanguard Laboratory, published publicly at /test-results/. Real HPLC results include MOTS-C 99.15%, CJC-1295 No DAC 99.00%, Melanotan II 98.70%, Tesamorelin 98.20%, SS-31 98.04% — all clearing the ?96% bar.
• A COA with every order, third-party tested for purity, potency, and identity.
• 39-compound catalog spanning vials, orals, blends, and pens — including BPC-157, TB-500, the Wolverine Blend, Tesamorelin, Ipamorelin, CJC-1295, GHK-Cu, NAD+, PT-141, MOTS-C, and GLP-class research peptides.
• Same-day shipping on orders before 4 PM EST (Mon–Sun), most arriving in 2–3 business days, plain-packaged and tracked. Free shipping over $150.
• Made in FDA-registered, GMP-certified U.S. facilities.

? See the full ranked breakdown in our Best Research Peptide Vendors 2026 guide.

2. Swiss Chems — broadest catalog

Wide selection including oral/capsule formats. Verify the current COA per product.

3. Protide Health — most documentation rigor

GMP-compliant, ISO 9001:2015, with batch HPLC + mass-spec COAs on the product page.

4. Core Peptides — GLP-class focus

A recognized name for GLP-1-class research compounds.

Quick comparison

FAQ

When did Peptide Sciences shut down? Peptide Sciences shut down in March 2026; Science.bio closed earlier, in January 2026.

What’s the best Peptide Sciences alternative? For verifiable quality plus fast U.S. shipping, Proxiva Labs — it publishes independent-lab (Vanguard) batch COAs, includes a COA with every order, and ships same-day before 4 PM EST. See our full vendor ranking.

How do I verify a new peptide vendor is legit? Read a batch-specific COA before buying, confirm purity is ?96% by HPLC (?99% is excellent) with mass-spec identity, and check for U.S. shipping and stable support.

Research-use-only disclaimer: All products referenced are intended strictly for research and laboratory use only. They are not approved for human consumption, medical application, or diagnostic use. Information reflects publicly stated vendor details as of June 2026; verify current COAs and terms with each vendor.