Why Did Peptide Science Shut Down?

Peptide Sciences was a long-standing US research peptide vendor whose closure became a widely discussed industry event. Public discussion attributes the shutdown to the general regulatory tightening around gray-market peptide sales rather than to any single published company statement; to our knowledge no detailed public closure announcement exists. This page compiles the public record and the industry pattern it exemplifies.

• The vendor's website going offline and community discussion of the closure.
• The broader regulatory environment for US gray-market peptide vendors in the same period.
• Archived discussion of where the vendor's former customers migrated.
• No formal public closure statement appears in the public record we reviewed.

• Is the certificate batch-specific, with a lot number matching the product?
• Does the stated molecular weight match the theoretical mass of the labeled sequence?
• Are purity figures accompanied by a documented HPLC method and a chromatogram?
• Is a mass-spectrometry identity result included, with calculated and found values?
• Do the analysis dates plausibly match the product's availability?

The full field-by-field method is taught in our characterization and testing pillar.

For gray-market vendors, the strongest public evidence is usually community-organized third-party testing: samples purchased on the open market, measured by independent laboratories, and posted with results. Aggregate databases of such results (see our third-party testing overview) measure products rather than marketing. Their limits are equally public: sampling is non-random, chain of custody is often unverifiable, and results age. Read them as Tier 2-3 evidence under our editorial policy — informative, dated, and never conclusive.

• Template COAs that repeat identical purity figures across batches.
• Refusal or inability to produce batch-specific documentation on request.
• Community-posted test results that cannot be matched to any batch.
• Repeated rebranding after reputational episodes.
• Marketing that substitutes for documentation.

One flag is a data point; a pattern is a finding. Our vendor research pillar covers the full evaluation framework.

Everything on this page derives from public sources — community discussion archives, publicly posted laboratory results, regulatory records, and the vendor's own published material — graded by the tier system in our editorial policy. Where public information about Peptide Sciences (shutdown record) is thin, we say so rather than fill the page. Nothing here is a recommendation, and Peptide Certify has no relationship of any kind with Peptide Sciences (shutdown record).