Peptide Sciences Review (2026): Is It Still Open?

By Russel Martin, Editor · Updated November 4, 2026 · Editorial policy

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Peptide Sciences was one of the best-known research peptide vendors in the US. Several third-party sources report that its website went dark on 6 March 2026 with a notice that the company had voluntarily shut down. We could not confirm this with the company: its site refused our automated check on 4 November 2026, and we found no statement from the company itself.

What researchers should know

Treat the company as reported closed until it says otherwise.
A well-known brand name that has gone quiet is easy to copy. If a site uses the Peptide Sciences name, check its domain, company details and COAs before you order.
US searches for the brand fell from about 135,000 a month in January to about 22,000 in September 2026 (Semrush), which matches researchers moving to other vendors.

Looking for another supplier? See our Peptide Sciences alternatives, which compares the vendors that are still trading.

What we could not verify

Whether the original site is closed, redirecting or open to logged-in customers only.
Any current prices, shipping or refund terms.

Facts were checked on 2026-11-04 from the vendor's own pages. Vendors change prices and policies, so check the current page before ordering. See how we review.

Frequently asked questions

Is Peptide Sciences still open?

What are the alternatives to Peptide Sciences?

We compare the research peptide vendors that are still trading on testing, shipping, refunds and company details. See our Peptide Sciences alternatives page.

Sources

peptidesciences.com/ (checked 2026-11-04)
peptideprotocolwiki.com/blog/peptide-sciences-shut-down (checked 2026-11-04)
thepeptidelist.substack.com/p/peptide-sciences-is-dead-inside-the (checked 2026-11-04)
trustpilot.com/review/peptidesciences.com (checked 2026-11-04)