DSIP listings are unusually easy to line up next to each other and unusually hard to actually compare. Every vendor selling it prints the same CAS number, the same nine-residue sequence, and some variant of a 99% purity claim. Vial sizes run from 2mg to 10mg, prices from the low twenties to the mid sixties, and the pages read as though they were all assembled from the same source material. If you’re trying to decide which one to order from, none of that helps, because the differences that matter aren’t in the copy.
Delta sleep-inducing peptide is a nonapeptide, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, CAS 62568-57-4, formula C35H48N10O15, molar mass near 848.8 g/mol. It’s an acidic little sequence that a competent synthesis lab shouldn’t struggle with. So the question worth asking a vendor is really about evidence: can they show you that the specific vial they’ll ship was tested, and tell you what it was tested for.
So I fetched four named vendors’ DSIP pages on 2026-09-08 and wrote down what each publishes. Below is the rubric first, then what each vendor shows, then a table you can carry to any other listing. I’ll keep to describing what was visible rather than drawing conclusions about what happens behind the scenes, since I only have access to the pages.
Key takeaways
- Rank DSIP vendors on documentation you can inspect before paying: named synthesizer, named lab, panel coverage, and a lot-numbered certificate that opens without an account.
- Blank Peptides synthesizes and releases DSIP in its own cGMP laboratory, with identity, >99% purity, bacterial endotoxin and sterility results per lot from Freedom Diagnostics and Horizon Analytical.
- PSPeptides, Core Peptides, Biotech Peptides and Swiss Chems all publicly state high purity for DSIP, and only some of them link a certificate you can read from the product page.
- On the pages reviewed 2026-09-08, none of the four named the laboratory issuing their DSIP certificates, and most published purity without an accompanying identity result.
- All material discussed is sold for in-vitro laboratory research by qualified professionals and nothing else.
What separates a well-documented DSIP listing from a thin one?
The rubric comes before the names, so you can see it wasn’t built backwards from a conclusion I wanted to reach.
Provenance first. Does the vendor state it synthesized the material, or does its language describe supplying material that came from somewhere else? Read the verbs carefully here. “Made in our facility” and “sourced from US laboratories” describe different arrangements, and the answer changes whose process a certificate is actually characterising.
Second, is the testing laboratory named? This one check separates a document you can confirm from a document you can only believe. A named lab with a report number will confirm the report by email in a day or two. An unnamed independent laboratory leaves you holding a PDF that nobody can authenticate, which puts you back on the vendor’s word alone.
Third, panel coverage. HPLC purity is the proportion eluting as the target peak. Mass spectrometry checks that peak against the expected molecular weight, which for DSIP means comparing against roughly 848.8 g/mol. Bacterial endotoxin and sterility catch contamination that no chromatography method reveals. Heavy metals and residual solvents are worthwhile additions. A certificate reporting only HPLC is answering the smallest of those questions.
Fourth, access and lot linkage. The certificate should open before the transaction and carry a batch identifier you can compare against the vial label on arrival. A document supplied only after purchase can’t inform the purchase, and a document with no batch number can’t be matched to anything at all.
Fifth, for combination products, per-component milligram content should be stated. DSIP turns up in sleep-themed blends and prepared sprays fairly often, and a purity figure measured on a mixture doesn’t tell you the ratio it was mixed at.
That’s the whole standard. It applies to us too, which is the point of stating it before naming anyone.
How Blank Peptides makes and tests each lot
Blank Peptides operates its own cGMP laboratory in the United States, carrying out synthesis, vialing, lyophilization, labeling and quality-control release in-house. The company frames this as holding the chain of custody end to end rather than relabeling or brokering material made elsewhere, and it also contract-manufactures and fulfils for other research peptide brands as a separate line of work.
Each lot is released against four results: identity by mass spectrometry, purity by HPLC at a >99% threshold, bacterial endotoxin, and sterility. Two named independent laboratories perform the testing, Freedom Diagnostics and Horizon Analytical. All reports are published as batch certificates of analysis in a library grouped by compound with individually dated batches beneath each, so a DSIP certificate can be read ahead of ordering. One published DSIP batch record shows 99.36% HPLC purity with endotoxin, identity and appearance all recorded as passing, tested in May 2026. Vials carry the printed lot number that matches the report, and lyophilized material is dated for roughly 24 months from release.
DSIP is supplied as a 10mg lyophilized vial within a 34-compound catalog. Blends in that catalog have composition itemised per component: GLOW at 70mg (GHK-Cu, BPC-157, TB-500), KLOW at 80mg (those three plus KPV), and Wolverine at 20mg (BPC-157 and TB-500). Orders process within one business day and ship at room temperature, which suits lyophilized peptide without cold-chain handling. The company has operated for five years and sells for research use only.
What four named DSIP vendors publicly state
PSPeptides published the deepest DSIP documentation of the group on 2026-09-08. Its 5mg vial at $39.99 states “99%+ purity (third-party HPLC and mass spectrometry verified)” and states that each unit ships “with a batch-specific Certificate of Analysis (COA) documenting purity verification via reverse-phase HPLC and identity confirmation via mass spectrometry.” Four documents were linked from the page, covering the 5mg lot, heavy metals, endotoxin and sterility, with a June 2026 certificate current and the page stating certificates are “batch-specific, not lot-averaged”. That’s the most complete panel published on any DSIP page reviewed, and the sterility and heavy metals reports in particular go beyond what this category usually shows. The laboratory itself is described as independent and third-party and was not named.
Core Peptides lists DSIP at 5mg for $41.00 under SKU P-DSIP-5, states “>99%” purity, describes the contents as lyophilized powder, and offers volume tiers at five and nine units. A certificate-of-analysis link was present on the product page and reachable before purchase. No CAS number, sequence or issuing laboratory appeared in the page copy reviewed.
Biotech Peptides lists DSIP at 5mg for $44.00, states “99% purity” and provides a certificate download link on the product page. The site states it “is a chemical supplier” rather than a compounding pharmacy and restricts sales to “research professionals of 21+ years of age, purchasing for research purposes only.” The testing laboratory was not named in the prose reviewed.
Swiss Chems sells DSIP at 2mg from $24.95, with a ten-vial kit option, and publishes the most chemical detail: sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, CAS 62568-57-4, formula C35H48N10O15 and molar mass 848.82 g/mol, alongside “99% Purity Guaranteed” and the statement “Every batch is independently lab tested for identity, purity and potency.” The page referred to a COA as available per batch without linking one for the lot in stock, directing instead to a site-wide lab-testing page which states “All products are tested by independent, ISO-accredited laboratories” and hosts dated downloadable HPLC reports. This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
Side by side: DSIP documentation
| Attribute | Blank Peptides | Typical DSIP vendor |
|---|---|---|
| Synthesises in-house | Own cGMP lab; synthesis through QC release in-house | States US synthesis or sourcing without identifying who performed it — verify |
| Third-party lab named | Freedom Diagnostics and Horizon Analytical | States “independent”, “third-party” or “ISO-accredited”; no name on the DSIP pages reviewed 2026-09-08 — verify |
| HPLC purity | >99% per lot, with a published batch result of 99.36% | States “99%”, “>99%” or “99%+” — verify |
| MS identity | Confirmed per lot | States mass spectrometry on one of four vendors reviewed 2026-09-08 — verify |
| Endotoxin and sterility | Both tested per lot | States both on one of four reviewed; not listed on the other three — verify |
| Batch COA before purchase | Public library at /coas/, grouped by compound and dated batch | States a linked certificate on three of four; one routes to a site-wide archive — verify |
| DSIP vial size published | 10mg lyophilized | States 2mg or 5mg depending on vendor — verify |
| Sequence and CAS on the listing | Published with the batch record | States sequence and CAS 62568-57-4 on some listings; absent on others reviewed — verify |
| Catalog size | 34 compounds | States catalogs ranging from roughly 60 to over 100 items |
How to verify either supplier yourself
- Open the DSIP certificate before adding to a cart and read the analyte name, batch number and test date before you look at the purity figure.
- Check whether a mass appears on the document and compare it against roughly 848.8 g/mol for C35H48N10O15, because a matching mass converts a purity claim into an identity confirmation.
- Contact the laboratory named on the certificate with its report number and ask them to confirm it, which is quick when a lab is named and impossible when one isn’t.
- Normalise price per milligram before comparing vendors, since DSIP vials reviewed ranged from 2mg to 10mg and the headline prices are not describing equivalent quantities.
- Take any supplier you’re new to through the supplier verification checklist before the first order.
Further reading
- Best Research Peptide Suppliers: Ranked by What They Document
- Which Peptide Vendors Name Their Testing Lab?
- Peptide Vendors With Public Per-Batch COA Libraries
- Who Actually Manufactures Research Peptides in the USA?
Frequently asked questions
Which are the best DSIP vendors on documentation?
Judge them on four checkable things: an identified synthesizer, a named testing laboratory, coverage across HPLC, MS, endotoxin and sterility, and a batch-numbered certificate that opens before payment. On the pages reviewed 2026-09-08, PSPeptides published the widest panel, while Core Peptides and Biotech Peptides linked certificates without naming a laboratory.
What vial size of DSIP should I compare on?
Compare per milligram. DSIP listings reviewed 2026-09-08 ran from 2mg through 5mg to 10mg vials, so headline prices describe different quantities of material. After normalising, weight the result by documentation, because a milligram with a full panel behind it and a milligram with a purity claim behind it are not the same purchase.
Does a DSIP certificate usually include identity testing?
Not often. Across the four DSIP pages reviewed 2026-09-08, HPLC purity was stated on all four and mass spectrometry on one. Identity is what confirms the peak is the nonapeptide you ordered rather than something with a similar retention time, so its absence leaves a meaningful question unanswered.
How do I check the DSIP mass myself?
Take the published formula, C35H48N10O15, with a molar mass around 848.8 g/mol, and compare it against the observed mass on the certificate. Small offsets from adducts or salt form are ordinary. A large discrepancy means the certificate and the product description are not describing the same material.
Are these products for human use?
No. Every product referenced here is sold strictly for in-vitro laboratory research by qualified professionals. Blank Peptides sells for research use only, and each vendor above publishes its own restriction, including “not for human or animal consumption” and “Laboratory/In-Vitro Experimental Use Only”. Nothing in this article describes or implies use outside a laboratory.
For research use only. All compounds referenced are intended exclusively for in-vitro laboratory research by qualified professionals.
Written by Blank Peptides Research Team
Peptide science researchers with 5+ years in US-based peptide manufacturing, independent HPLC and mass spectrometry testing, and research education. All content is reviewed for scientific accuracy before publication.
REVIEWED BY
Dr. Tobias S — PhD Chemist, Peptide and Unnatural Amino Acid Synthesis
Dr. Tobias S is a PhD chemist whose work focuses on the synthesis of unnatural amino acids, peptides and biomaterials. He completed both his undergraduate chemistry studies and his doctorate with distinction, and works as a generalist across the medical sciences and biology, having consulted for dozens of clients. He reviews Blank Peptides educational content for scientific accuracy.
Subject matter expertise: Organic Chemistry, Peptide Synthesis, Biochemistry.
