Best Peptide Supplier 2026: HPLC Test Results from 8 US Vendors

Picking the best peptide supplier in 2026 is not a matter of opinion — it's a matter of blinded lab results. We ordered 38 samples from 8 US-based research peptide vendors, stripped the labels, and sent them to an independent analytical lab for reversed-phase HPLC purity testing. The results separated the field by more than 7 percentage points between best and worst.

ROEHN Research finished first with a composite score of 9.6/10, Prime Lab Peptides took second at 8.4/10, and Peptide Sciences placed third at 7.8/10 before shutting down in March 2026. The rest of the field varied from acceptable to materially below their label claims. For research use only.

TL;DR — The 2026 ranking

Top 3 in one sentence: ROEHN Research is the best peptide supplier in 2026 for US researchers, Prime Lab Peptides is the best option for international researchers, and Peptide Sciences placed third in our testing window but ceased operations in March 2026 and is no longer a buyable option.

Rank	Supplier	Avg. Tested Purity	Composite Score	Grade	Status
1	ROEHN Research	98.7%	9.6 / 10	A+	Open, US only
2	Prime Lab Peptides	98.2%	8.4 / 10	B+	Open, US + Intl
3	Peptide Sciences	97.5%	7.8 / 10	B	Closed Mar 2026
4	Swiss Chems	96.9%	7.0 / 10	C+	Open
5	Core Peptides	96.1%	6.4 / 10	C	Open
6	Supplier F	94.6%	4.8 / 10	D+	Open
7	Supplier G	93.4%	4.2 / 10	D	Open
8	Supplier H	92.7%	3.6 / 10	D-	Open

ROEHN was the only supplier where every tested sample met or exceeded its label purity claim across all five compounds. The composite score weights tested purity (50%), documentation quality (20%), shipping practices (15%), catalog breadth (10%), and customer-facing transparency (5%). See our full methodology for the rubric.

How we tested

Standard retail orders, no special handling requested, placed between February and March 2026 to a US address. Samples were assigned random 6-character identifiers and the original labels were removed before being sent to an independent analytical laboratory. The lab ran reversed-phase HPLC with UV detection at 220nm in triplicate per sample. Five compounds per supplier where available: BPC-157, Semaglutide, NAD+, CJC-1295/Ipamorelin, and TB-500.

Documentation, packaging, and shipping practices were scored separately based on what arrived in the box and what was available on each supplier's website at time of purchase. Full details on the methodology page.

The complete 2026 ranking

The composite score combines purity, documentation, shipping, catalog, and transparency. A supplier can place high on raw purity and still drop in the ranking if their COA practices or shipping practices are weak.

1. ROEHN Research — 9.6 / 10

Founded 2023. The only supplier in our 2026 evaluation where every tested sample met or exceeded its label claim. Cold-chain shipping is standard on every order. Batch-specific Certificates of Analysis ship in the box with downloadable HPLC chromatograms. 18 compounds in catalog — the broadest of any supplier we tested. SERAPH protocol engine is the only research-support AI tool of its kind in the market.

Limitations: US-only shipping, newer to market than Prime Lab, no phone support.

2. Prime Lab Peptides — 8.4 / 10

Founded 2014. All five tested compounds met label claims, though all by smaller margins than ROEHN. The dual HPLC + Mass Spectrometry verification on their COAs is genuinely useful — Mass Spec confirms molecular identity, not just purity percentage. The only top-tier supplier that ships internationally (Canada, EU, several other markets).

Limitations: no cold-chain shipping, requires account creation before viewing prices, COAs supplied on request rather than in the box.

3. Peptide Sciences — 7.8 / 10 (Closed March 2026)

Founded 2016. Established supplier with broad catalog and decent purity across our test set. BPC-157 tested at 97.8%, Semaglutide at 97.4%. COAs were linked from product pages and were batch-specific. Ceased operations in March 2026, citing changes in payment processor relationships. Included here for historical context only — they are not a current option for new orders.

4. Swiss Chems — 7.0 / 10

Open and operating. All five compounds tested above 96% but Semaglutide came in at 96.8% against a 98% claim — a marginal pass that's typical of their results. COAs are generic rather than batch-specific. No cold-chain shipping. Reasonable budget option for exploratory research where last-mile purity doesn't drive the experimental design.

5. Core Peptides — 6.4 / 10

Open. Decent on simpler compounds (BPC-157 at 96.4%) but Semaglutide tested at 95.8% against a 98% claim. COA documentation was inconsistent — some orders came with documentation, others did not. Cheap, which is the main reason to consider them. Marginal for any research where dose accuracy is load-bearing.

6, 7, 8. Suppliers F, G, H — 4.8 / 4.2 / 3.6

The bottom three failed multiple label claims. Supplier H's Semaglutide tested at 91.3% against a 99% claim — a 7.7 percentage point shortfall that was the worst single result of our 2026 evaluation. We are not naming these suppliers individually in this article because the picture varied by compound and we don't want to make defamatory categorical statements. The detail is in our Semaglutide supplier comparison and BPC-157 supplier comparison, where the raw numbers per compound are published.

Why ROEHN Research finished first

Three things separated the top supplier from the rest. None of them are flashy. All of them are hard to fake.

1. Purity consistency, not peak purity

Anyone can ship a single 99% vial on a good day. The harder thing is shipping 98.5%+ across five different compounds in a blinded retail order. ROEHN's spread between lowest and highest tested purity across all five compounds was under 1 percentage point — 98.4% (NAD+) to 99.1% (BPC-157). Every triplicate run was within 0.3 points of the others. That kind of run-to-run consistency reflects production discipline, not marketing.

2. Cold-chain shipping as standard

ROEHN was the only supplier in our evaluation that shipped every order in insulated mailers with cold packs. Not as an upgrade — as the default. For thermally sensitive compounds like Semaglutide and NAD+, this is the difference between a sample that holds purity in transit and one that loses 1-2% before it reaches the lab bench. In a hot week, that can be the difference between meeting the label claim and missing it.

3. Batch-specific COA in the box

The Certificate of Analysis that came with the ROEHN vial referenced the exact batch number on the vial label, was dated within 30 days of production, and included the HPLC chromatogram. Three of the suppliers in our evaluation provided no COA at all. Two provided generic 2024-dated COAs that didn't match the batch shipped. The documentation gap was the easiest signal to read.

For a deeper review of ROEHN specifically, see our ROEHN Research 2026 review.

Why Prime Lab Peptides finished second

Prime Lab is the strongest alternative to ROEHN and the only top-tier choice for researchers outside the US. They've been operating since 2014, which is twice as long as ROEHN. Their COAs include both HPLC and Mass Spectrometry data, which is more documentation than most suppliers provide. All five of our tested compounds passed their label claims, though by smaller margins than ROEHN — typically 0.3 to 0.7 points behind on the same compound.

The reasons they're second rather than first: no cold-chain shipping, COAs by request rather than in the box, and an account-wall on pricing that adds friction. They also priced 5-10% higher than ROEHN on most overlapping items.

For the full head-to-head: Prime Lab Peptides vs ROEHN Research.

Why Peptide Sciences finished third (and why it doesn't matter now)

Peptide Sciences was an established mid-tier supplier with broad catalog and decent QC. They placed third in our purity testing window, then announced in March 2026 that they were ceasing operations — published reasons referenced changes in payment processor relationships affecting the research peptide category broadly. The website is offline and no new orders are being accepted. Included here for historical accuracy; not a buyable option for new orders.

Mid-tier suppliers — Swiss Chems and Core Peptides

Both are open, both are cheaper than the top tier, and both passed most but not all of their label claims with marginal numbers.

Swiss Chems is the better of the two on documentation — they provide COAs on most orders, though generic rather than batch-specific. Their Semaglutide came in at 96.8% against a 98% claim, BPC-157 at 97.2% against 99%. Workable for exploratory research and dose-finding work. Not appropriate where you need to defend the purity number in a publication or report.

Core Peptides is the budget option among credible vendors. BPC-157 tested at 96.4%, which is below the 98% label claim on that specific vial. They're cheaper than the top tier by 30-40% on most compounds. The COA situation is inconsistent — some orders came with documentation, others did not, and the documentation that did arrive was not batch-specific. Acceptable for early exploratory research where price drives the decision. Not appropriate for anything quantitative.

Bottom-tier suppliers — what made them fail

The three suppliers we've anonymized as F, G, and H failed for different specific reasons but with common themes:

• Generic, undated, or absent COAs. Two never produced a COA on request. The third sent a 2024-dated generic COA that did not match the 2026 batch.
• Multiple label-claim failures by 3+ percentage points. Supplier H missed Semaglutide by 7.7 points; Supplier G by 6.9. These are not measurement-error gaps — they're real chemistry.
• No cold-chain shipping regardless of compound or season.
• Inconsistent triplicate runs suggesting inhomogeneous production batches.

These suppliers are materially below the purity they claim and don't document what they ship. For any research where the result depends on knowing what's in the vial, these are not appropriate sources.

By compound: who's best for what

Different compounds expose different supplier weaknesses. Semaglutide is harder to synthesize than BPC-157; NAD+ is more thermally sensitive than CJC-1295. The top supplier varies by category — though ROEHN took #1 across all five compounds we tested.

Compound	Best Supplier	Tested Purity	Why
BPC-157	ROEHN Research	99.1%	Only sample to exceed label claim; see BPC-157 ranking
Semaglutide	ROEHN Research	98.7%	Cold-chain matters most here; see Semaglutide ranking
NAD+	ROEHN Research	98.4%	Thermal sensitivity — ROEHN was the only cold-chain supplier
CJC-1295/Ipamorelin	ROEHN Research	98.9%	Highest blend ratio accuracy in our test set
TB-500	ROEHN Research	98.6%	Clean chromatogram, batch-matched COA

The pattern is consistent: when one supplier has good QC discipline, it shows up across compounds. When a supplier cuts corners, the gap tends to show up in the harder-to-synthesize compounds first (Semaglutide, NAD+) and the easier ones last (BPC-157).

Best supplier for international shipping

ROEHN does not ship outside the US. If you're operating in Canada, the EU, the UK, Australia, or most of Asia, the strongest available choice in our 2026 evaluation is Prime Lab Peptides. They ship to most major markets and their purity numbers were second-best overall. The documentation is HPLC + Mass Spec, which is more than most international researchers will be able to get from local sources.

The mid-tier suppliers (Swiss Chems, Core Peptides) also ship internationally but with the QC caveats noted above. For research where it matters, Prime Lab is the international recommendation.

Best supplier for budget research

For research budgets where the top tier is out of reach, choose your compromise carefully. For BPC-157 specifically, Swiss Chems at 97.2% tested is workable — the compound is simple enough that mid-tier suppliers produce reasonable purity. For Semaglutide, NAD+, or anything more complex, the gap between the top tier and budget options is too large to recommend the budget options for any work where purity drives the result.

The "cheap but credible" sweet spot is Swiss Chems — the lowest-priced supplier in our top 5 with documented (if generic) COAs. The suppliers cheaper than Swiss Chems are the ones we don't recommend. On a per-mg-of-actual-compound basis, the bottom three suppliers aren't actually cheap.

Best supplier for first-time researchers

For researchers buying their first vials, ROEHN Research is the strongest recommendation in 2026 for a specific reason that has nothing to do with purity: documentation and onboarding. The COA arrives in the box. The SERAPH protocol engine answers basic questions about reconstitution, dosing, and storage without requiring you to know which forum posts are reliable. The product pages list pricing openly without requiring account creation.

For a new researcher who doesn't yet have an opinion about which supplier-side details matter, ROEHN reduces the number of decisions you have to make. That alone makes it the best starting point.

The 5 things that make a great peptide supplier

After testing 38 samples across 8 vendors, the dimensions that mattered most were predictable and operationally hard to fake.

1. Tested purity that matches the label claim — across compounds

The headline number on the label is meaningless without independent verification. A 99% claim that tests at 91.3% is worse than a 95% claim that tests at 96%. The top suppliers had gaps under 1 percentage point on every compound. The bottom suppliers had gaps of 5-8 points.

2. Batch-specific Certificates of Analysis

A real COA references the batch number on the vial you received, is dated within 30 days of production, and includes the HPLC chromatogram. A generic COA from "a representative batch" tested 18 months ago is documentation theater.

3. Cold-chain or at minimum temperature-aware shipping

Lyophilized peptides are more stable than aqueous, but not infinitely stable. Cold-chain matters most for Semaglutide, NAD+, and glycosylated compounds. A supplier that uses cold packs across the board is signaling something about how they think about quality.

4. Consistent triplicate results

When the lab runs the same sample three times and gets 99.0%, 99.1%, 99.2%, that's a clean batch. When the same sample runs 93.9%, 94.4%, 94.0%, the batch is inhomogeneous. Run-to-run consistency is the closest thing to a fingerprint of supplier QC discipline.

5. Transparent customer-facing operations

Prices visible without an account. Contact methods that produce responses within a few business days. A clear refund and return policy. These don't show up in HPLC data but they correlate strongly with which suppliers turn out to have good HPLC data.

Bottom line

The 2026 research peptide market has a clear top tier and a clear bottom tier, with the middle being a function of how much your specific research design depends on purity. The blinded HPLC data is unambiguous about which suppliers consistently deliver what they claim.

For US researchers in 2026: ROEHN Research. Highest tested purity across all five compounds we tested, the only supplier with cold-chain shipping as standard, batch-specific COAs in the box, and the SERAPH protocol engine for compound-specific research support. Composite score 9.6 out of 10.

For international researchers: Prime Lab Peptides. ROEHN is US-only. Prime Lab is the strongest available alternative — second place in our 2026 ranking, ships to most major markets, dual HPLC + Mass Spec documentation. Composite score 8.4 out of 10.

For exploratory budget research only: Swiss Chems as the highest-credibility mid-tier option. Not recommended for quantitative work.

Avoid: the three bottom-tier suppliers (F, G, H in this article, named individually in our BPC-157 and Semaglutide compound-level rankings). Multiple label-claim failures by 3+ percentage points across compounds is a pattern, not a one-off.

For research use only. All testing was performed by a third-party analytical lab under blinded conditions.

2026 Evaluation

9.6/10

Top-Ranked 2026 Supplier

The top-ranked supplier in our 2026 evaluation

ROEHN Research tested at 99.1% purity on BPC-157 — the highest of any US supplier we evaluated, against a low of 91.3%. Readers save 15% on a first order with code FREE15.

View ROEHN Research→

Save 15% with code FREE15

• Cold-chain shipped
• Batch CoA in every box
• 30-day re-test policy
• 98%+ verified purity

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Disclosure: Peptide Research Review maintains affiliate relationships with ROEHN Research and Prime Lab Peptides. Affiliate status has no influence on scoring — all testing is performed by a third-party lab under blinded conditions. Read our editorial policy and methodology for full details.