Research Library
Short, sourced reference articles for researchers who buy peptides for in vitro work: how to read a certificate of analysis, what HPLC purity and net content mean, how lyophilized material is handled and stored, and what the research-use-only rules require. Where an article cites one of our lab reports, the figures are read from the certificate on file and link to it in the COA Library.
Articles
- Research noteComparisons
Selank vs Semax: Molecular Differences and Research Evidence
Selank and Semax share one design feature, a C-terminal Pro-Gly-Pro tail, and little else: Selank is built from the immunoglobulin fragment tuftsin, Semax from a fragment of adrenocorticotropic hormone. Most published work studies one compound or the other, so most of the two literatures cannot be compared at all. Five studies examined both within the same experiment, and those are the only sources supporting direct comparison. This guide sets out what has been compared, what has not, and what the certificates for the two products record.
November 9, 2026 - Research noteCompound Guides
Semax Peptide: Structure, ACTH Origin and the Research Record
Semax is a synthetic heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro, derived from adrenocorticotropic hormone with a Pro-Gly-Pro tail added for stability. The literature describes it under two names that look contradictory but refer to the same molecule. Published chemistry shows that acetylating its N-terminus changes copper coordination and removes a protective effect in a cell model, so N-acetyl Semax is a different compound. This guide covers the structure and naming, the preclinical record, the limits of the human reports, and what our certificate does and does not establish.
November 8, 2026 - Research noteCompound Guides
Selank Peptide: Molecular Structure, Mechanism, and Research Overview
Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, built from the immunoglobulin fragment tuftsin with a Pro-Gly-Pro extension added to slow its breakdown. Its formula, molecular weight and CAS number are in PubChem, so a certificate can be checked against a public record. The mechanism research is mostly preclinical and not settled: a positive allosteric effect on GABA binding is proposed, yet a human cell line showed no direct transcriptional effect. This guide covers the structure, the evidence and its limits, and what our Selank certificate does and does not establish.
November 7, 2026 - Research noteCompound Guides
IGF-1 LR3: Structure, Binding-Protein Affinity and the Research Record
IGF-1 LR3, or Long-[Arg3]-IGF-I, is a recombinant analogue of insulin-like growth factor-I with a 13-amino-acid N-terminal extension and arginine in place of glutamate at position 3. NMR work shows the folded core is essentially that of IGF-I, with the differences at the N-terminus, where IGF-binding proteins make contact. Its greater potency is not intrinsic: without binding proteins present it has been reported as less potent than native IGF-I. This guide covers the structure, the binding-protein and receptor evidence, laboratory uses, and our certificate for lot PPL-IG1-1.
November 7, 2026 - Research noteCompound Guides
KLOW Peptide Blend: Composition, Laboratory Analysis and Published Research
KLOW is a lyophilised blend of four peptides, labelled 50 mg GHK-Cu, 10 mg BPC-157, 10 mg TB-500 and 10 mg KPV. Published research covers the compounds separately; a PubMed search on November 7, 2026 found no study of the four-component combination. Our current lot's certificate identifies and quantifies each component, shows that the headline purity is an average of four separate purities, and finds that the component labelled TB-500 has the mass of full-length thymosin β4.
November 7, 2026 - Research noteCompound Guides
KPV Peptide: Molecular Structure, Mechanisms and Published Research
KPV (Lys-Pro-Val, α-MSH 11-13) is a 342 Da tripeptide cut from α-melanocyte-stimulating hormone. Published research consists of cell-culture experiments, mostly measuring NF-κB activity, and rodent or rabbit models, mostly of colitis; uptake through the PepT1 transporter and partial independence from melanocortin receptors are reported. A PubMed and ClinicalTrials.gov search on November 7, 2026 located no controlled human trial of unmodified KPV. This guide separates KPV from its analogues and formulations and shows what our certificates measure.
November 7, 2026 - Research noteCOA and Testing
Peptide Purity vs. Net Content: Understanding the Difference
HPLC purity is the main peak's share of total peak area: it says how much of the detected peptide material is the target compound. Net peptide content is the mass of peptide in the vial, measured against a reference standard and compared with the label claim. Counter-ions, water, residual solvent and fill mass change content without changing purity, which is why a 99.99 % pure lot can measure 9.22 mg in a 10 mg vial and another lot 58.15 mg in a 50 mg vial.
November 7, 2026 - Research noteCOA and Testing
How to Read a Peptide Certificate of Analysis (COA)
A peptide certificate of analysis reports what an independent laboratory measured on one sample of one lot: identity, chromatographic purity, net content against the label claim, the methods used and the specifications applied. This guide explains each field using three genuine Precise Pep Labs certificates, and shows what a purity percentage can and cannot tell you.
November 6, 2026
Browse by topic
- COA and Testing
How certificates of analysis, HPLC purity, identity, endotoxin and lot traceability work for research peptides.
2 articles
- Compound Guides
Reference notes on individual research peptides: structure, sequence, documented in vitro literature and handling.
5 articles
- Comparisons
Side-by-side reference comparisons of related research compounds and formats.
1 article