Peptide Sciences is closed, and there's no authorized replacement site. Its website still shows a shutdown notice that calls any site claiming affiliation with it fraudulent (checked September 26, 2026). Of the eight vendors we review, Peptide Plugs (8.1/10) and NextGenPeps (8.0) score highest on our transparency method, because both name their labs on their own sites. None of the eight has a long, independent test record, so check each one before your first order.
Notice: Research peptides are sold for in-vitro laboratory research only. They are not FDA-approved, not for human or animal consumption, and this page is not medical advice.
What happened to Peptide Sciences
Peptide Sciences, widely described as the largest US research peptide vendor, announced its closure on March 6, 2026 (PeptideLaws.com; legal commentary from Lumalex Law). When we checked peptidesciences.com on September 26, 2026, it still displayed the notice:
- "After careful consideration, Peptide Sciences has decided to voluntarily shut down operations and discontinue the sale of its research products."
- "Any website, platform, entity, or individual claiming affiliation with Peptide Sciences ... is unauthorized, fraudulent, and has no affiliation with our company."
The notice gives no reason and says nothing about open orders or refunds. The closure came during a period of repeated FDA warning letters to research peptide sellers; our shutdown timeline lists them with sources.
What to check before you switch
A closure like this creates openings for copycat sites and rushed decisions. Before you order from anyone new:
- Ignore anything using the Peptide Sciences name. Per its own notice, no site is authorized to claim affiliation. Science.bio, which closed in January 2026, posted a similar impostor warning on its site.
- Search the FDA warning letter database. Look up the vendor's name in FDA's database. One of our eight, Swiss Chems, has a letter from December 2024.
- Match a certificate to your lot, and confirm it with the lab. A COA with no lab name, no lot and no date isn't evidence. Check whether the lab offers a lookup, such as Freedom Diagnostics' accession search or Janoshik's verification. Our COA guide and COA checklist cover each field.
- Look for independent data. Finnrick publishes results from samples customers buy and submit. As of our September 26-28, 2026 checks, only Swiss Chems among our eight had any, and it passed 4 of 10 (Finnrick).
- Check who you're dealing with. Does the site publish a legal entity and address? How old is the domain? Several vendors in our list registered their domains in 2025 or 2026.
- Read the payment, returns and chargeback terms. Card payments carry dispute rights under the Fair Credit Billing Act; the FTC says crypto payments "typically are not reversible" (FTC). Several of our vendors say all sales are final.
Eight alternatives at a glance
Listed in our editors' order, which isn't sorted by score. Checked September 26, 2026 (Licensed Peptides September 28, 2026).
| Vendor | Score | Best for | Lab named on site | Ships to | Our code |
|---|
| American Peptides | 9.1 | Lot lookup, international | Homepage only (Bioviridian) | US and 215 countries | None |
| NextGenPeps | 8.8 | Named labs, PayPal | Yes (Janoshik, BioRegen) | US and territories | None |
| PSPeptides | 8.5 | Speed, payment range | No (on PDFs) | US, Canada, EU, UK, Australia | CHECKED (10%) |
| Ascension Peptides | 8.1 | Lot search, first-order price | Product pages | US only | AFFILIATE50OFF (50% first order) |
| Peptide Plugs | 7.5 | Lab-side verification | Yes (Freedom Diagnostics) | US only | None |
| Swiss Chems | 6.5 | Long history, overnight shipping | FAQ only (Janoshik) | US and international | None |
| Licensed Peptides | 7.4 | Endotoxin reports, 2-day shipping | Yes (Vanguard, Ethos) | US only | Affiliate5 (5%) |
| Alpha Pro Peptides | 6.3 | Net content per lot | No (on PDFs) | US only | None |
Alternatives by use case
Lab-side COA verification: Peptide Plugs (7.5)
Names Freedom Diagnostics on its site, lists 117 dated certificates, and gives accession codes you can check on the lab's COA search. Publishes Austin Research Products LLC, Liberty Hill, TX. Gaps: December 2025 domain, 0 Finnrick tests, "Weight Loss"-style categories, US only. Review · Visit Peptide Plugs
Lab named on every report: NextGenPeps (8.8)
Its COA library names Janoshik or BioRegen on each dated entry, with endotoxin results on some batches. Publishes NUTRL LLC, San Diego, and is the only one of our eight that lists PayPal. Gaps: no lot numbers in the library, no Finnrick profile, coded GLP-1-class items, USPS only. Review · Visit NextGenPeps
Lot-number lookup and international shipping: American Peptides (9.1)
Enter your vial's lot on its verify page to pull the matching certificate (126 on file). Ships to 215 countries and territories, per its international page. Gaps: February 2026 domain, lab named only on the homepage, health-style bundle names, free shipping only over $300, and a strict chargeback clause. Review · Visit American Peptides
Net content for each lot: Alpha Pro Peptides (6.3)
Its testing page lists lot ID, date, purity and measured net content, with Freedom Diagnostics certificates. Gaps: February 2026 domain, no address, no Finnrick profile, coded GLP-1-class items and capsules, no Mastercard. Review · Visit Alpha Pro Peptides
Lot search and the lowest first-order price: Ascension Peptides (8.1)
An 85-record COA library searchable by lot, with labs named per batch on product pages (Kovera Labs, MZ Biolabs). AFFILIATE50OFF takes 50% off a first order (coupon page). Gaps: no address, 0 Finnrick tests, six coded items, $15 flat shipping, US only. Review · Visit Ascension Peptides
Long history and overnight shipping: Swiss Chems (6.5)
Operating since 2018 (per its site), with dated batch reports and FedEx Overnight. It's the only one with Finnrick data, but that data is weak: 48%, 4 of 10 passed. It also received an FDA warning letter in December 2024. Review · Swiss Chems alternatives · Visit Swiss Chems
Endotoxin reports and 2-day shipping: Licensed Peptides (7.4)
Names Vanguard Laboratory and Ethos Analytics on its purity reports page and posts LAL endotoxin reports. Publishes Licensed Peptides, Inc., Boca Raton, FL (contact). Same-day dispatch on orders paid before 4 PM PST, free FedEx 2-Day over $200 (shipping), all checked September 28, 2026. Affiliate5 takes 5% off (coupon page). Gaps: some reports appear to reuse lot numbers across products, Trustpilot removed its profile, May 2025 domain, no Finnrick profile, coded GLP-1-class items, US only. Review · Visit Licensed Peptides
Fast shipping and payment range: PSPeptides (8.5)
Same-day shipping on orders before 2PM EST, free UPS 2nd Day Air over $200, international shipping, and the widest payment range we track. Trustpilot shows 4.2/5 from 175 reviews. CHECKED takes 10% off (coupon page). Gaps: its blog publishes human dosing guides, no lab named on its site, November 2025 domain. Review · Visit PSPeptides
No vendor on our list is a like-for-like replacement, and a clean FDA record for a young business says less than it would for an older one. Pick based on what you can verify: a named lab, a lot-matched certificate you can confirm at that lab, and a published business identity. Recheck before each order, because vendors in this market can close quickly.
For the full list with ratings, see best peptide vendors in the USA. Related: third-party tested peptides · peptide coupon codes · how to store peptides · peptide calculator
Other closures: Science.bio · Amino Asylum · Paradigm Peptides · PureRawz
Rank 1
