Last checked: October 29, 2026.
The 30-second answer
The best peptide vendors in 2026 prove every lot. We don't rank named sellers. We publish a 100-point rubric instead, led by lot-specific COAs, mass-spec identity, HPLC purity with the chromatogram and a named independent lab. Five deal-breakers score any vendor zero.
Why a list goes stale
Peptide Sciences was the biggest name in the market. On March 6, 2026, it shut down. A "best vendors" list written in January was wrong by spring. Is Peptide Sciences shut down?
Lots change, labs change and vendors close. Criteria last. So instead of a list, here's the scoring sheet, and you can use it on anyone. That includes us.
In this article you'll learn:
- The five deal-breakers that end the scoring on the spot
- How the 100 points are split, and why proof outweighs price
- How ProGrade scores itself on the same sheet, in public
How does the rubric work?
Think of a restaurant health inspection. The grade comes from what the inspector can check in the kitchen, not from the menu photos.
This rubric works the same way. 65 of the 100 points go to documents you can check yourself: the COA, identity data, purity data and the lab behind them.
A COA (certificate of analysis) is a lab report card for one batch, or "lot." The weights follow the failure data. In 2024 test buys, three vials labeled 99% pure measured 7.7% to 14.37%. [1] Purity and identity get the most points because they fail the most.
Step 1: Which five deal-breakers end the scoring?
Any one of these sets the score to zero. Stop there.
| Deal-breaker | Why it's absolute |
|---|---|
| No lot-specific COA before purchase | Without one, every other criterion is unverifiable |
| COA lot doesn't match the vial | The document describes a different product |
| Human-use marketing (dosing charts, injection guides, testimonials) | FDA's August 2026 warning letters cited dosing information, injection instructions, dose calculators and bacteriostatic water for injection prep [7] |
| Copycat identity (a closed brand on a new domain) | peptidesciencesinc.com, registered Apr 17 2026, is unaffiliated and on registrar clientHold |
| Crypto-only or off-site payment | Removes chargeback rights. In 2024 test buys, 3 of 6 orders never arrived, and scammers demanded $650–$1,200 in fake "customs" fees [2] |
The human-use rule isn't a style choice. Under 21 CFR 201.128, intended use shows up in "labeling claims, advertising matter, or oral or written statements." A research-only label doesn't cancel a dosing chart. [8]
Did you know? In one 2024 study, 3 of 6 online test orders never arrived. The sellers then asked for up to $1,200 more to "clear customs." [2]
Step 2: How are the 100 points split?
Score each criterion as full, half or zero points.
| Criterion (points) | Full points | Half points | Zero |
|---|---|---|---|
| 1. Lot-specific COA, public (20) | Every product, every lot, viewable before purchase, with test date | Some products, or only on request within 24 hours | (Deal-breaker) |
| 2. Identity by mass spectrometry (15) | Observed vs. expected mass on the COA, spectrum attached | Mass stated, no spectrum | HPLC only |
| 3. HPLC purity, shown not told (15) | ≥99% with the chromatogram and method attached | ≥98%, or a number without chromatogram | <98%, or no purity data |
| 4. Independent, named lab (15) | Named third-party lab, ISO/IEC 17025 accredited, confirms reports on request | Named third-party lab, accreditation unclear | In-house or unnamed lab |
| 5. Safety screens (10) | Endotoxin (LAL/BET) in EU/mg and heavy metals per lot | One of the two, or "pass" with no number | Neither |
| 6. Content accuracy (10) | Net peptide content, water and counterion data; per-component data for blends | Quantity stated per vial, no content assay | Combined blend numbers only |
| 7. Cold chain and storage (5) | Insulated packaging, cold packs, storage temps on label and site | Storage temps stated, standard packaging | Nothing stated |
| 8. Policies and business transparency (10) | Legal entity, address, written refund/reship terms covering failed retests | Policies exist, retest failures not covered | No policies or no entity |
Total: 100 points.
What does the score mean?
| Score | Meaning |
|---|---|
| 85–100 | Strong. The documents support the label |
| 70–84 | Acceptable. Close the gaps with an independent retest of your first lot |
| 50–69 | Weak. Retest before any lot enters an experiment |
| Under 50 | Avoid |
Why do the weights look like this?
COA and identity: 35 points
A COA is the only link between a lab result and the vial in your hand. That's why it's worth 20 points, and why missing one is a deal-breaker. A lot-specific COA works like a best-by date stamped on one carton. It tells you about that carton, not the brand.
Identity gets 15 more because purity can't confirm it. HPLC is a race where each molecule crosses the finish line at its own time. It reports what share of the signal sits in the main peak. Mass spectrometry is a scale that weighs the molecule, confirming it's the sequence on the label.
USP and MHRA scientists list mass spectrometry, NMR and amino acid analysis as identity tests, separate from purity. [3]
Purity: 15 points, with the chromatogram
A number on a PDF is a claim. The chromatogram (the HPLC trace) is the evidence. You can see the main peak, the impurity peaks and whether the baseline was cropped.
Full points start at 99% because that's the figure vendors advertise. The 2024 test buys show what an unsupported 99% claim can hide: 7.7% to 14.37% measured purity. [1]
Guide: HPLC vs. mass spectrometry
Independent lab: 15 points
ISO/IEC 17025 is the international standard that lets testing labs "demonstrate that they operate competently and generate valid results." [9] Accreditation covers a set scope of methods, so check that the scope includes HPLC or LC-MS.
An unnamed lab can't be called. A named lab can confirm that report X matches lot Y. Do that once per vendor.
Lab landscape: Peptide testing labs explained
Safety screens: 10 points
Endotoxin is the "smoke" left behind by dead bacteria. Sterile filters can't catch it, so it has to be tested. The test is the bacterial endotoxins test in USP <85>, the subject of FDA's pyrogen and endotoxin guidance. [10]
One 2024 test-buy vial measured 8.9511 EU/mg (endotoxin units per milligram). [1] Ask for the number, not the word "pass."
Heavy metals matter too. Falsified peptide products seized in Belgium carried arsenic and lead, some at up to 10× the ICH limit for injectable drugs. Purity of the cysteine-containing peptides in that set ranged from 5% to 75%. [5]
Guide: Endotoxin (LAL) testing explained
Content accuracy: 10 points
Freeze-dried powder holds peptide plus water plus counterions, such as TFA or acetate. USP lists Karl Fischer titration for water and HPLC for counterions. [3]
Purity doesn't capture any of that. Two custom peptides reported at 98.44% and 98.34% HPLC purity contained 20% and 43% w/w undeclared mannitol. [4]
Did you know? The 2024 test-buy vials held 28.56% to 38.69% more semaglutide than labeled. An overfilled vial is still the wrong vial for any experiment that depends on concentration. [1]
Cold chain: 5 points
Freeze-dried peptides are stable, not invincible. In a 2015 study of freeze-dried secretin, samples were kept at 25°C and 60% relative humidity. Particle size grew from about 390 nm to over 2 µm within one week. [6]
It gets 5 points, not more, because you control storage once the vial arrives. You can't control the box in transit.
Guide: Peptide storage and handling
Policies and transparency: 10 points
A refund policy that covers a failed independent retest puts the vendor's money behind its COA. A named legal entity and address give you someone to hold to it.
Peptide Sciences customers with pending orders had no official recovery process. Card chargebacks were the fallback.
What this means for you: Most of the score comes from paperwork you can check in minutes. If a vendor won't show it, the score tells you what you need to know.
What does a scored vendor look like?
These two vendors are invented to show the math. They aren't real companies.
| Criterion | Vendor A | Vendor B |
|---|---|---|
| 1. Lot COA (20) | 20: every lot posted | 10: on request only |
| 2. MS identity (15) | 15: spectrum attached | 0: HPLC only |
| 3. HPLC purity (15) | 15: 99.3% with chromatogram | 7.5: "99%+," no chromatogram |
| 4. Independent lab (15) | 7.5: named, accreditation unclear | 0: "in-house QC" |
| 5. Safety screens (10) | 5: endotoxin only | 0 |
| 6. Content accuracy (10) | 5: quantity stated, no assay | 5: quantity stated |
| 7. Cold chain (5) | 5 | 2.5 |
| 8. Policies (10) | 10 | 5 |
| Total | 82.5: acceptable, retest first lot | 30: avoid |
Vendor B's price could be half of Vendor A's. It doesn't change the score. Price isn't a quality criterion.
Myth vs. fact
| Myth | Fact |
|---|---|
| "The biggest vendor is the safest bet." | The biggest name, Peptide Sciences, shut down on March 6, 2026. |
| "99% on the label means 99% in the vial." | Three 2024 test-buy vials labeled 99% measured 7.7% to 14.37%. |
| "A cheaper vendor must be cutting corners, and a pricier one must be better." | Price earns no points either way. Score the documents. |
| "An in-house lab is as good as an outside one." | An unnamed in-house lab is the vendor grading its own homework. |
How do you score a vendor in 20 minutes?
- Deal-breakers first. Whois the domain (look up who registered it, and when). Scan the site, blog and social accounts for human-use content. Check payment options at checkout.
- Open three product pages. Find each COA without logging in. Note lot numbers and test dates.
- Read one COA closely. Lab name, method, purity, chromatogram, observed mass, endotoxin, heavy metals. How to read a certificate of analysis
- Check the lab. Look up its accreditation and scope. Email it to confirm one report.
- Read the policies. Refund, shipping, terms, legal entity.
- Fill in the table. Total it, then compare against the bands.
Your next step: switching from Peptide Sciences? Start with the deal-breaker checklist: How to choose a Peptide Sciences alternative. Then score us: See the ProGrade COA library.
How does ProGrade score on its own rubric?
We're a vendor, so we have a conflict of interest. Our answer is to score ourselves on the same rubric, in public. We'll fill in each score when the evidence is live on our site, and we won't publish a total until every row is backed.
| # | Criterion | ProGrade evidence | Score |
|---|---|---|---|
| 1 | Lot COA, public | COA published per lot before purchase COA library | Pending |
| 2 | MS identity | Third-party HPLC/MS testing per lot | Pending |
| 3 | HPLC purity | ≥99% per lot | Pending |
| 4 | Independent lab | Not yet published on this page | Pending |
| 5 | Safety screens | Not yet published on this page | Pending |
| 6 | Content accuracy | Per-component data on blends (e.g., Wolverine 10 mg + 10 mg) | Pending |
| 7 | Cold chain | Not yet published on this page | Pending |
| 8 | Policies | Not yet published on this page | Pending |
| Total | Published once every row is evidenced |
Deal-breaker check: no human-use marketing. Every product is sold for laboratory research use only.
If you score us differently, send us your sheet. We'll publish corrections.
Did the 2026 FDA and HHS moves change the rubric?
No. (Last checked October 29, 2026.)
On July 23–24, 2026, FDA's Pharmacy Compounding Advisory Committee voted to recommend BPC-157, KPV and TB-500 (8–6) and MOTS-c (7–5) for the 503A bulks list. That's FDA's list of raw ingredients pharmacies can use to mix a drug for one patient. Epitalon and semax were also recommended. [11]
On October 28, 2026, HHS issued an interim enforcement-discretion policy for 503A compounding of BPC-157, TB-500, KPV, MOTS-c, epitalon and semax. In plain English, HHS won't act against licensed pharmacies that compound those six in named forms and routes, on a prescription. It excludes 503B outsourcing facilities (larger, FDA-registered compounders). HHS dates the end of Category 2 status, FDA's red-flag list, to April 22, 2026. [12]
That isn't FDA approval, and rulemaking continues. It doesn't cover research-use-only products. It doesn't change how research vendors are judged, and it doesn't move any criterion in this rubric.
Explainer: The FDA's July 2026 peptide vote, explained
The evidence in detail
| Study | What it tested | Key findings used in the rubric |
|---|---|---|
| Ashraf et al., 2024, JMIR | Online semaglutide sellers; test buys | Vials labeled 99% measured 7.7%–14.37%; 28.56%–38.69% more peptide than labeled; one vial at 8.9511 EU/mg endotoxin |
| Ashraf et al., 2024, JAMA Netw Open | Six no-prescription test orders | Three never arrived; $650–$1,200 fake "customs" fees demanded |
| McCarthy et al., 2023, Pharm Res (USP/MHRA authors) | Reference standards for synthetic peptides | MS, NMR and amino acid analysis as identity tests; Karl Fischer for water; HPLC for counterions |
| Choules et al., 2019/2020, J Pharm Biomed Anal | Two commercial custom peptides | 98.44% and 98.34% HPLC purity; 20% and 43% w/w undeclared mannitol |
| Janvier et al., 2018, Talanta | Falsified peptide drugs, Belgian market | Arsenic and lead, some up to 10× the ICH parenteral limit; cysteine-peptide purity 5%–75% |
| Srinivasan et al., 2015, Int J Pharm | Freeze-dried secretin stability | Particles ~390 nm → >2 µm within 1 week at 25°C/60% RH |
Conflict note: ProGrade is a vendor and wrote this rubric. The worked-example vendors are hypothetical. The cited studies name specific sellers; this article doesn't.
For research use only. Not for human consumption. These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
References
- Ashraf AR, Mackey TK, Vida RG, et al. Multifactor quality and safety analysis of semaglutide products sold by online sellers without a prescription. J Med Internet Res. 2024;26:e65440. pmc.ncbi.nlm.nih.gov/articles/PMC11582493/ (doi:10.2196/65440)
- Ashraf AR, Mackey TK, Schmidt J, et al. Safety and risk assessment of no-prescription online semaglutide purchases. JAMA Netw Open. 2024;7(8):e2428280. pmc.ncbi.nlm.nih.gov/articles/PMC11297364/
- McCarthy D, Han Y, Carrick K, et al. Reference standards to support quality of synthetic peptide therapeutics. Pharm Res. 2023;40(6):1317+. pmc.ncbi.nlm.nih.gov/articles/PMC10338602/
- Choules MP, Bisson J, Simmler C, et al. NMR reveals an undeclared constituent in custom synthetic peptides. J Pharm Biomed Anal. 2020;178:112915. pmc.ncbi.nlm.nih.gov/articles/PMC6913887/
- Janvier S, Cheyns K, Canfyn M, et al. Impurity profiling of the most frequently encountered falsified polypeptide drugs on the Belgian market. Talanta. 2018;188:795–807. europepmc.org/article/MED/30029448
- Srinivasan C, Siddiqui A, Korang-Yeboah M, Khan MA. Stability characterization and appearance of particulates in a lyophilized formulation of a model peptide hormone, human secretin. Int J Pharm. 2015;481(1–2). pubmed.ncbi.nlm.nih.gov/25636302/ (abstract re-checked 2026-10-29 for the 25°C/60% RH particle-size figure)
- McDermott Will & Schulte. Federal regulators and state boards crack down on RUO peptides. Sept 24, 2026. www.mcdermottlaw.com/insights/federal-regulators-and-state-boards-crac…
- 21 CFR 201.128, Meaning of "intended uses." eCFR. www.ecfr.gov/current/title-21/chapter-I/subchapter-C/part-201/subpart-…
- ISO. ISO/IEC 17025: Testing and calibration laboratories. www.iso.org/ISO-IEC-17025-testing-and-calibration-laboratories.html
- FDA. Pyrogen and Endotoxins Testing: Questions and Answers (guidance; concerns USP <85> Bacterial Endotoxins Test). www.fda.gov/regulatory-information/search-fda-guidance-documents/pyrog…
- FDA. July 23–24, 2026: Meeting of the Pharmacy Compounding Advisory Committee. www.fda.gov/advisory-committees/advisory-committee-calendar/july-23-24… (opened 2026-10-29 in the reader-first pass; tallies per the batch-2 brief's verified list)
- HHS. Enforcement Discretion Policy Regarding 503A Compounding Using Certain Peptide Bulk Drug Substances, with Appendices A and B. www.hhs.gov/sites/default/files/hhs-503a-peptide-enforcement-discretio… ; Federal Register doc. 2026-22192 (public inspection Oct 28, 2026; publication Oct 30, 2026): www.federalregister.gov/d/2026-22192 (both opened 2026-10-29)
Research use only
This article is provided for educational and informational purposes and summarizes published laboratory and preclinical research. All ProGrade Peptides products are sold strictly for in-vitro laboratory and research use only (RUO). Nothing here is medical advice, a therapeutic claim, or a protocol for human or animal use. These compounds are not intended to diagnose, treat, cure, or prevent any disease.
Frequently asked questions
We don't name or rank vendors, because quality is lot-specific and vendors close. Use the 100-point rubric instead. Vendors scoring 85 or higher show lot COAs, mass-spec identity, HPLC chromatograms, a named accredited lab, safety screens and clear policies.
Lot-specific COAs (20 points), mass-spectrometry identity (15), HPLC purity with the chromatogram (15) and an independent named lab (15). Together they make up 65 of 100 points.
No. In 2024 test buys of online semaglutide, vials labeled 99% measured 7.7% to 14.37% purity. Look for the chromatogram, the testing lab's name and mass data on a COA that matches your lot.
Price says nothing about what's in the vial. A low price earns no points, and neither does a high one. Score the documents, then compare prices among vendors that clear 85.
It posted a shutdown notice on March 6, 2026 and hasn't relaunched as of October 29, 2026. Sites claiming to be its successor are unaffiliated.
Drafted with AI assistance and fact-checked against the cited sources by The ProGrade Research Desk. See our editorial policy and sourcing policy. Spot an error? Report it.
