On March 6, 2026, Peptide Sciences posted a three-sentence notice on their homepage and went dark. No warning to customers, no guidance on pending orders, no explanation beyond "voluntary."
For thousands of researchers who relied on Peptide Sciences as their default vendor, the question is simple: where do you go now?
We've tracked peptide vendors across pricing, COA testing, product availability, and reliability for months. Here are the alternatives worth considering — and what to watch out for during the transition.
Why Did Peptide Sciences Shut Down?
Peptide Sciences was one of the largest grey-market research peptide vendors in the US. Their catalog covered most popular compounds — BPC-157, semaglutide, retatrutide, growth hormone secretagogues, and dozens more.
The shutdown didn't happen in a vacuum. Three forces converged in late 2025 and early 2026:
1. FDA enforcement accelerated. Federal agencies increased actions against vendors selling peptides under "research only" disclaimers, questioning whether the research-only model constituted a legal distinction or a loophole.
2. Pharmaceutical companies filed lawsuits. Eli Lilly and Novo Nordisk targeted grey-market suppliers of their patented GLP-1 compounds (semaglutide, tirzepatide), creating legal exposure for any vendor carrying these products.
3. Quality testing revealed problems. Independent third-party testing by Janoshik Analytical showed quality inconsistencies across the Peptide Sciences catalog. Retatrutide was the most problematic — receiving failing grades across 37 tested samples collected between December 2024 and March 2026, with at least one counterfeit detection flagged. If you were running retatrutide from Peptide Sciences and switching to a new vendor, double-check your retatrutide dosing against the verified concentration on the new product — under-dosed lots from the prior supplier mean the protocol you were running may not match milligram-for-milligram on a COA-tested replacement.
Update (March 16): Just days before Peptide Sciences shut down, HHS Secretary RFK Jr. announced that 14 of the 19 banned peptides will return to legal compounding. This means BPC-157, TB-500, and most popular peptides will soon be available through licensed pharmacies with a prescription — a regulated alternative to the grey-market model that Peptide Sciences operated under.
The combination of legal pressure, litigation risk, and quality questions likely made continued operations untenable.
Is "Peptide Sciences Inc" (peptidesciencesinc.com) the Real Rebrand?
Short answer: no — there is no evidence that peptidesciencesinc.com is the original Peptide Sciences relaunched. Industry counsel has publicly warned that multiple sites have appeared since the shutdown claiming to be the rebrand, and that none of them are confirmed successors. The original Peptide Sciences has not announced a relaunch under any new URL.
The site frames itself as the original company returning "with enhanced discretion following legal challenges." That framing doesn't survive a closer look at why the company actually shut down:
- Criminal liability, not branding, drove the shutdown. By late 2025, the Department of Justice had moved past civil warning letters and secured guilty pleas from individuals tied to grey-market peptide distribution. For the principals at a $7.4M/month operation, the risk profile shifted from "business risk" to "personal prison risk." Relaunching under a near-identical brand recreates the exact liability they walked away from.
- The SAFE Drugs Act explicitly targets the model. The proposed federal legislation introduced in early 2026 would prohibit the sale of research chemicals that are biologically identical to FDA-approved drugs without a New Drug Application. A real Peptide Sciences successor would be relaunching directly into that legal pipeline.
- The original site's shutdown notice was final and unconditional. No customer-list migration, no forwarding URL, no advance notice to affiliates or distributors. Pending orders were silently cancelled. None of that matches a planned rebrand.
- The economics of a "discreet rebrand" don't add up. Walking away from $89M/year in annualized revenue voluntarily, then relaunching the same model under a similar name, would be the worst possible legal strategy. It re-establishes intent and continuity for a hypothetical prosecutor.
The far more likely explanation is that peptidesciencesinc.com is an opportunistic impersonator trading on brand recognition residual. Several scam sites launched within days of the March 6 shutdown — this domain fits that pattern.
What to actually do if you landed on peptidesciencesinc.com looking for the original vendor:
- Don't transact with it. There is no verified connection to the original company.
- Check the domain registration date (whois lookup). Domains registered in March 2026 or later, with privacy-shielded registrants, are textbook impersonator-vendor red flags.
- Use the alternative vendors below, all of which have 12+ months of community track record and verifiable COA documentation.
What to Look for in an Alternative Vendor
Not every vendor that appears in the wake of a major shutdown deserves your trust. Some pop up specifically to capture displaced customers. Here's what actually matters:
Third-party COA testing — A Certificate of Analysis from an independent lab confirms purity and identity. Vendors that publish COAs for every batch are investing in quality verification. Those that don't are asking you to trust their word alone.
Established track record — Vendors operating for 12+ months with consistent product quality and shipping reliability are safer than brand-new operations appearing after the shutdown.
Transparent pricing — Clear prices per vial with dosage amounts listed. No hidden fees, no bait-and-switch on concentrations.
Product catalog depth — Vendors carrying 20+ peptides signal operational maturity. A five-product catalog suggests a dropshipper, not a supplier.
5 Best Peptide Sciences Alternatives
We rank vendors using a weighted scoring system: price (40%), COA verification (30%), and reputation (30%), with a floor score of 8.0. All vendors listed below have been operating for 12+ months and are monitored continuously.