Substance K is supplied as white lyophilized powder with molecular formula C50H80N14O14S and molecular weight 1188.4. Substance K, also known as neurokinin A, is a decapeptide of the tachykinin family that preferentially activates the NK2 receptor. It is used in respiratory research to study bronchoconstriction and airway hyperresponsiveness, and in gastrointestinal work to examine smooth muscle contraction and transit. Neuropharmacology laboratories apply it to pain signaling models and to the characterization of NK2-selective antagonists. In binding studies it provides a high-affinity reference ligand, and in functional assays it is often compared with substance P to distinguish receptor subtype contributions. Delivery is arranged through tracked courier services covering most research destinations. Standard transit uses ambient conditions, which is appropriate for lyophilized peptide powders; ice packs are available for customers who prefer additional thermal protection. Consolidated dispatch is offered so that a laboratory ordering a panel of peptides receives one parcel rather than several, which reduces both freight cost and administrative workload. The lyophilized cake is stable for 24 months when kept sealed at minus 20 degrees Celsius in a dry environment. Brief exposure to ambient temperature during weighing does not compromise the material provided the vial remains closed. After reconstitution, keep solutions on ice during the experimental session and discard any remainder rather than refreezing. For peptides containing cysteine, consider adding a mild reducing agent if the assay is sensitive to disulfide-mediated oligomerization. Quotations, custom fill masses and logistics questions are handled by Aurora, reachable on WhatsApp at +852 4423 6619 or by email at 18963519387@163.com. A short message listing the product name, quantity and destination is sufficient for us to confirm stock, price and the expected delivery schedule, and to advise on packing if the material must travel to a humid or remote location. Purity is determined by integration of the main peak in reverse-phase HPLC chromatograms, and identity is confirmed by mass spectrometry before release. Water content is kept within the range specified for lyophilized peptide powders to limit hydrolytic degradation during storage. Where a research protocol requires it, we can supply the chromatogram, the mass spectrum and the calculated peptide content for the corresponding lot, so that the material can be entered into a laboratory quality system with full traceability. Vials are packed under controlled humidity, sealed, and then cushioned inside a rigid outer carton. Available formats include 1 mg, 5 mg, 10 mg and 50 mg, with custom fill masses for projects that require a specific quantity per experiment. Labels record the lot number and the analytical release date. We can also supply kits in which several related peptides are packed as a matched set, which is convenient for comparative structure-activity studies run within a single laboratory. YIWU SHUNXIAN TRADING CO., LTD. serves the global research community as a supplier of high-purity peptides and laboratory consumables, with a operating model built around consistency, documentation and reliable delivery. Qualified raw materials are sourced against defined specifications, processed through purification and lyophilization, and released only after analytical confirmation of purity and identity. We support research teams in academic institutions, contract laboratories and biotechnology companies, and we understand that the practical requirements of these groups differ: some need small exploratory quantities, others require repeated bulk supply against a fixed specification. Our logistics arrangements are designed to accommodate both, and our communication is direct, technical and oriented towards solving the actual problem a laboratory faces.