Peptide Sciences Shut Down (March 2026): Status and Listings

Peptide Sciences, a US online seller of research peptides, shut down in March 2026 and is not back online: on September 24, 2026, peptidesciences.com still showed only its closure notice, with no store or product listings. An archived capture of the site dated March 8, 2026 shows the store replaced by a notice stating that the company "made the decision to voluntarily shut down operations and discontinue the sale of our research products." The notice gives no further reason, and since at least March 21, 2026 it has also said that no website or seller claiming to be Peptide Sciences or its successor is connected to the company. Pepta Labs has no connection to Peptide Sciences and does not sell its inventory. Below are the dated records, and the Pepta Labs listings that carry the same compound name as items on Peptide Sciences' archived January 2026 menu.

Is Peptide Sciences closed?

Peptide Sciences is closed: it had stopped taking orders by March 8, 2026, the date of the first archived capture that shows its closure notice. The notice itself carries no date, and the capture before it, dated January 3, 2026, still shows the store, so this page gives the month the notice was first recorded, March 2026, rather than a day. The same month is recorded in the Peptide Sciences row of the peptide vendor shutdown tracker, which lists the US research peptide vendors that have closed or gone offline since December 2024.

What happened to Peptide Sciences?

Peptide Sciences shut down in March 2026 and has not reopened. Peptide Sciences' closure notice, first captured by the Internet Archive on March 8, 2026 (15:21:26 UTC), states that “after careful consideration, Peptide Sciences has made the decision to voluntarily shut down operations and discontinue the sale of our research products” and thanks its customers; the notice carries no date. The archive index holds no capture of the peptidesciences.com home page between January 3, 2026, when the store was open, and March 8, 2026, so the day the notice went up is not on record, and this page, like the tracker row, gives March 2026, the month of the first archived notice, rather than a day. Later captures show the notice reworded on March 21 and April 15, 2026 and unchanged on September 8, 2026. Pepta Labs checked peptidesciences.com again on September 27, 2026 and received an HTTP 403 bot-check page, so the September 24, 2026 browser check, which showed the notice only, is the latest page content confirmed.

Is Peptide Sciences back online?

No. As of September 24, 2026, Peptide Sciences is not back online: peptidesciences.com loads in a browser but shows only the closure notice, and nothing on the domain announces a reopening, a new store or a successor company. The notice has been revised twice since it first appeared, and each revision kept the shutdown in place. The table below lists every dated record this page relies on.

Is a site claiming to be the new Peptide Sciences genuine?

Peptide Sciences' own notice answers this: since at least March 21, 2026 it has said that any website, entity or individual claiming affiliation with Peptide Sciences, presenting itself as a successor, or claiming to sell its products is unauthorized and not connected to the company. The notice lists an email address for reporting such sites. This page does not name or link any such site. Pepta Labs makes no claim of affiliation with Peptide Sciences and sells no Peptide Sciences products; its listings are matched to Peptide Sciences items by compound name only.

Is peptidesciences.com still in business?

Not as a store. The domain is still online and carries the closure notice, but it has taken no orders since March 2026. The notice's April 2026 wording says the company keeps the rights to its name and trademarks; it does not say that sales will resume.

What is a Peptide Sciences alternative?

Pepta Labs lists 35 research compounds. The table below is built from a sourced snapshot: each row is a single-compound item on Peptide Sciences' product menu in the Internet Archive capture of January 3, 2026, matched to the Pepta Labs listing with the same compound name. Quantities are each seller's stated nominal quantity and often differ. Multi-compound blends and non-vial products are left out because their contents cannot be matched one to one. The switching guide has a Peptide Sciences section and sets out what every Pepta Labs order includes.

Of the single-compound vial items on that archived menu (capsule and topical products left out), 26 compound names match a Pepta Labs listing. Peptide Sciences also listed a separate "TB-500 Fragment (17-23)", the seven-residue piece LKKTETQ; Pepta Labs does not list that fragment. To compare listings on price per milligram, see research peptide price per mg, which reads every price from the live catalog.

Payment methods are shown at checkout. The cart shows the payment method for each item.

What does a Pepta Labs order include?

• Shipping: free US shipping, no minimum order. Orders ship to US addresses only (see the shipping terms).
• Account: Orders are placed from a free account with a confirmed email, so every order traces back to a real customer.
• Reports: Sent by email on request, before you order if you want to see it first.
• Dispatch: Most orders ship the next business day. Processing and delivery times are estimates, not guarantees.
• Returns: Unopened products in original sealed condition may be returned within 30 days of delivery with return authorization (see the returns terms).

For how the remaining US sellers are listed and dated, see best peptide vendors 2026. Eternal Peptides, which closed its website on September 15, 2026, has its own page: Eternal Peptides shut down.

What are the CAS numbers of TB-500, Thymosin Alpha-1, NAD+, Tesamorelin and GHK-Cu?

A compound name is only a label; the CAS number, molecular formula and molecular weight are what a mass-spectrometry report is checked against. TB-500, Thymosin Alpha-1, NAD+, Tesamorelin and GHK-Cu are the compound names searched most often together with "Peptide Sciences". The values below are the ones recorded for each Pepta Labs listing.

Why did Peptide Sciences shut down?

Peptide Sciences' closure notice, archived on March 8, 2026, says the company "made the decision to voluntarily shut down operations and discontinue the sale of our research products." It gives no further reason, and the April 2026 rewording adds none. Other explanations that circulate online are not tied to a primary source we have reviewed, so this page does not repeat them.

What should I do about an open Peptide Sciences order?

A buyer with an unfilled Peptide Sciences order has three practical steps, none of which depends on the site coming back online:

1. Keep the order confirmation, the payment record and any shipping emails.
2. Keep a copy of anything you send about the order. The closure notice gives no address for order questions; the only email address on the current notice is for reporting sites that claim to be Peptide Sciences.
3. If a paid order never arrives, contact your card issuer. Card disputes follow your card issuer's own deadlines, so check them early.

Do not pay a website that claims to be completing Peptide Sciences orders: the company's notice says no such site is affiliated with it. The vendor shutdown tracker records status changes for Peptide Sciences and other closed vendors as they are confirmed.

What if I already hold Peptide Sciences material?

Peptide Sciences' lab report pages went offline with its website, so any report you saved is now the only copy you can rely on; keep it with the vial. A saved report can still be read against the identity data above: the compound name, the observed mass and the expected molecular weight should agree. The guide to verifying a peptide COA walks through each field.

Was Peptide Sciences third-party tested?

Peptide Sciences' archived homepage of January 3, 2026 said that every product was tested by HPLC, mass spectrometry or both, and described that testing as taking place in the company's own analytical laboratory; the homepage names no outside laboratory. Its lab report pages are no longer online, and we have not reviewed an archived copy, so this page makes no further statement about what that testing covered and draws no comparison between the two vendors.

What testing does Pepta Labs represent?

Pepta Labs represents two tests: independent RP-HPLC purity and mass-spectrometry identity. The scope is set out below; the quality page and the Terms give the full text:

• Independent third-party HPLC purity analysis and mass-spectrometry identity confirmation, commissioned through the purchasing group on a sampled production run from the source. Pepta Labs does not test in-house.
• Sterility, endotoxin or LAL, potency, pharmaceutical-grade, cGMP, contaminant-panel and vial fill-quantity testing are not claimed.
• Vial labels identify the compound, quantity and research-use designation. They do not carry lot or batch numbers.
• Because testing is commissioned by the purchasing group, the client field may name the group or source rather than Pepta Labs, and supplier-identifying fields are redacted.

Purity on a Pepta Labs report is the RP-HPLC area percentage of the main peak; identity is the observed mass compared with the theoretical molecular weight of the compound. Net peptide content is not reported per listing, which is why the counter-ion matters when comparing quantities (see TFA vs acetate salts and net peptide content). The HPLC vs mass spectrometry guide explains what each method can and cannot show.

How is this status page checked, and what has changed?

Pepta Labs rechecks peptidesciences.com and the Internet Archive record at least once a month and dates each check in the status box above. Status is taken only from the company's own notice or a primary record; if a statement here is wrong, write through the contact page with the source, and the correction is recorded below with its date. The Updated date at the top of the page changes only when a check changes what the page says.

Frequently asked questions

Is Peptide Sciences closed, and when did it close?

Yes. Peptide Sciences, a US online seller of research peptides, had stopped taking orders by March 8, 2026, the date of the first archived capture that shows its closure notice. The notice itself carries no date, and the capture before it, dated January 3, 2026, still shows the store.

Is Peptide Sciences back online?

No. On September 24, 2026, peptidesciences.com showed only its closure notice, with no store. The latest archived copy of the page, dated September 8, 2026, shows the same notice, and no relaunch or successor has been announced on the domain.

What happened to Peptide Sciences in 2026?

Peptide Sciences posted a closure notice, first archived on March 8, 2026, saying it had made the decision to voluntarily shut down operations and discontinue the sale of its research products. The notice is undated and gives no other reason; the archive index has no capture of the home page between January 3, 2026, when the store was open, and March 8, 2026, so the closure is dated to March 2026.

Is Peptide Sciences back in business?

No primary record says so. The closure notice, last archived on September 8, 2026, is the company's latest statement as of September 27, 2026, when Pepta Labs checked peptidesciences.com and received an HTTP 403 bot-check page; the last check that loaded the page, on September 24, 2026, showed the notice only. The notice says that any website, entity or individual claiming to be Peptide Sciences or its successor has no affiliation with the company.

What is the Peptide Sciences shutdown status in 2026?

Shut down and not back. Peptide Sciences stopped taking orders in March 2026, the first archived copy of its closure notice being dated March 8, 2026; the notice was reworded on March 21 and April 15, 2026 without lifting the shutdown, and on September 24, 2026 peptidesciences.com still showed the notice only, with no store, relaunch or successor announced.

Does a Peptide Sciences promo code still work?

No. Peptide Sciences no longer takes orders, so its codes cannot be used, and they are not valid at Pepta Labs. Code FALL25 gives 25% off at checkout. US shipping at Pepta Labs is free with no minimum.

Was Peptide Sciences third-party tested?

Its archived homepage of January 3, 2026 said products were tested by HPLC, mass spectrometry or both in the company's own analytical laboratory, and named no outside laboratory. Its report pages are offline, so we make no further statement. Available Pepta Labs HPLC purity and MS identity documentation covers a sampled production run and is sent by email on request.

Where can former Peptide Sciences buyers find TB-500?

Pepta Labs lists TB-500 10 mg from $56.73, recorded as full-length thymosin beta-4: CAS 77591-33-4, C212H350N56O78S, 4963.44 Da. Peptide Sciences sold TB-500 in 2 mg x 10, 5 mg and 10 mg sizes. Available HPLC purity and MS identity documentation for a sampled production run is sent by email on request.

Where can former Peptide Sciences buyers find Thymosin Alpha-1?

Pepta Labs lists Thymosin Alpha-1 from $50.86 (thymalfasin, CAS 62304-98-7, C129H215N33O55, 3108.26 Da); the quantity is stated on the listing. Peptide Sciences sold it in 3 mg and 10 mg sizes. The cart shows the payment method for the item, and available HPLC and MS documentation for a sampled production run is sent by email on request.

Is Pepta Labs a Peptide Sciences alternative?

Pepta Labs lists 35 research compounds; 26 compound names from the vial items on Peptide Sciences' archived January 2026 menu match a Pepta Labs listing, including TB-500, Thymosin Alpha-1, NAD+, Tesamorelin and GHK-Cu. Available HPLC purity and MS identity documentation covers a sampled production run and is sent by email on request. Pepta Labs has no connection to Peptide Sciences and does not sell its inventory.

Sources

• Internet Archive captures of peptidesciences.com, at web.archive.org/web/{timestamp}/https://www.peptidesciences.com/: 20260103004819 (store open, product menu used for the matching table), 20260308152126 (closure notice text quoted above), 20260318074523 (notice without the paragraph on other websites), 20260321144057 (first capture with the paragraph on other websites), 20260415143103 (reworded notice) and 20260908050700 (latest archived copy).
• Internet Archive capture index for peptidesciences.com: the attempt of September 20, 2026 recorded an HTTP 403 response.
• Pepta Labs browser check of peptidesciences.com, September 24, 2026: closure notice only; check of September 27, 2026: HTTP 403 bot-check page.
• Internet Archive capture index (CDX) for https://www.peptidesciences.com/, read September 27, 2026: the only captures between January 3 and March 10, 2026 are 20260103004819, 20260308152126 and 20260309003249.
• Pepta Labs peptide vendor shutdown tracker, Peptide Sciences row (closure recorded as March 2026).
• Pepta Labs quality and testing disclosure and terms, for the testing, report, delivery-address and returns statements.
• Identity values (CAS number, formula, molecular weight) as recorded on each Pepta Labs product listing.

All products are supplied for laboratory research use only and are not for human or animal use.