Peptide Sciences shut down: how to choose an alternative

What did Peptide Sciences say when it shut down?

By March 8, 2026, the Peptide Sciences storefront had been replaced with a short notice: "After careful consideration, Peptide Sciences has made the decision to voluntarily shut down operations and discontinue the sale of our research products." The Internet Archive's previous snapshot of the site, from January 3, 2026, shows the store still operating.

The notice gives no reason for the closure and says nothing about open orders or account credit. When we last checked, on October 3, 2026, the site showed only the closure notice and a trademark warning.

Why did Peptide Sciences close?

No public source confirms why Peptide Sciences closed. Explanations for the closure circulate on other vendors' and affiliate sites, along with estimates of the company's sales. None of them is confirmed by Peptide Sciences or by a public record we could find, so we do not repeat them here. If a page tells you why Peptide Sciences closed, check whether it links to a primary source, and whether it is also selling you a replacement.

How do I choose an alternative to Peptide Sciences?

Check each lot's certificate of analysis, who issued it, and what it actually tests. Start with the certificate of analysis. A useful certificate covers a specific lot, names the laboratory that ran the analysis, gives the date, and reports a measured purity rather than a minimum. Ask whether the lot on the certificate matches the batch you receive. Our COA library lists every certificate we hold in that form, including the compounds that do not have one yet.

Check who issued the certificate. Some are issued by the testing laboratory directly; others are prepared by a supplier and name a laboratory. Both can be legitimate, but they are not the same thing, and a supplier should tell you which you are looking at. We label ours.

Check what the certificate actually tests. Purity by HPLC tells you how much of the sample is the main compound. Identity testing, by mass spectrometry or against a reference standard, tells you the main compound is the one on the label. Not every certificate does both; our testing page shows what each of ours reports.

Read the rest of the site with the same care. A supplier whose product pages contradict its own terms, or whose policies on shipping and refunds disagree with each other, is a supplier whose continuity is harder to rely on. Consistent research-use framing, published policies and per-lot documentation are signs of a business built to last.

Where do I start on this site?

Browse the catalogue by research areas, each of which lists its compounds with their certificates. Every product page shows the certificate on file, who supplied it, and the laboratory it names.

Sources

1. Peptide Sciences homepage with closure notice, Internet Archive snapshot of March 8, 2026 (web.archive.org, source 1, accessed October 9, 2026)
2. Peptide Sciences homepage, Internet Archive snapshot of January 3, 2026 (web.archive.org, source 2, accessed October 9, 2026)