Frag 17-23 Supplier China: Sequence and COA Guide

Define residue boundaries and the complete short sequence

Write the parent reference, exact 17-23 boundaries, complete seven-residue sequence, residue order, N-terminal acetylation or other modifications where applicable, C-terminus, counterion form, target purity, 10mg content, quantity and RUO status. Record Frag 17-23 and any TB4-related aliases separately. Require the supplier to use one controlled construct and SKU across the quotation, specification, COA, analytical sample, label and packing list. The word fragment alone is not sufficient identity.

Do not treat Frag 17-23 and TB-500 as automatic synonyms

Marketplace naming can apply TB-500 to different synthetic fragments or product concepts. Ask the supplier to state exactly what was synthesized and prohibit substitution based on a pathway, parent-protein or nickname match. Compare the sequence, boundaries, acetylation, termini, expected mass and CAS reference where used. A full-length material, a different thymosin fragment or an unmodified seven-residue peptide is a different procurement item. Resolve conflicts before accepting price, samples or analytical documents.

Review mass evidence for acetylation and sequence target

Require complete batch-specific HPLC and MS files and compare observed molecular information with the expected value for the approved sequence and terminal state. Check sample ID, chromatogram, integration, method reference, dates, report number and authorization. An unexplained mass difference may indicate a missing modification, wrong counterion interpretation or different construct. HPLC purity cannot compensate for a wrong identity target, and a mass match alone cannot prove residue order, purity or exact content.

Verify 10mg content separately from HPLC purity

Ask what quantitative method or controlled filling record supports 10mg and what tolerance applies. Establish whether the label means net target fragment or total lyophilized mass including water, acetate or excipients. Keep sequence and modification identity, chromatographic purity and quantitative content in separate acceptance fields. Reconcile parent-lot and finished-lot quantities where applicable. Compare offers by total documented target peptide and equivalent method scope, not merely kit count, vial appearance or purity percentage.

Control labels, storage evidence and recurring batches

Approve labels showing Frag 17-23, strength, lot and RUO wording without unqualified equivalence claims. Obtain supplier-supported storage and transport conditions for the exact form. Map seller, synthesis, testing, filling, release, stock and shipping roles. Require COA, analytical attachments, SDS, specification, labels, invoice and packing list to agree. At receipt, inspect product, strength, lot, quantity and seals and quarantine sequence, modification, content or document discrepancies until a traceable quality decision is completed.

Build one comparable wholesale RFQ matrix

Send every candidate the same fields: controlled identity, strength, vial count, total material, target purity or composition, identity method, quantitative-content basis, offered lot, testing status, packaging, documents, MOQ, lead time and shipping term. Mark missing answers as exceptions instead of filling gaps with assumptions. Separate testing, setup, customization and transport costs from recurring unit price. A standardized matrix gives scientific, purchasing and quality reviewers one auditable record and prevents an incomplete offer from appearing cheaper simply because it describes less work.

Apply a batch-focused quality-control review

Define every required attribute, acceptance criterion, method and record before purchase. Use the quality-control framework to connect each supplier claim to evidence and its method scope. Check sample identifiers, dates, report numbers, units and lot relationships across the complete reports. Batch-specific evidence is more decision-useful than a representative certificate. Preserve original files, record revisions and investigate contradictions before approving shipment. Where risk warrants, arrange independent testing under a documented sampling and custody plan.

Create a documentation gate before dispatch

List the required batch COA, analytical attachments, SDS, specification, supported storage statement, label proof, invoice and packing list in the RFQ and purchase order. Reconcile product, strength, lot, quantity and revision across records with the documentation guide. Require replacement documents when the offered lot changes. The importer remains responsible for current destination requirements. Research-use wording improves clarity but cannot guarantee customs entry or replace destination-specific legal and broker review.

Verify supplier and batch ownership

Document the legal seller, manufacturing site, analytical laboratory, filling or packaging site, inventory owner, release authority and dispatch entity for the exact SKU. A trading or coordination company can work with qualified partners, but roles and accountability must be transparent. Ask who owns the batch record, authorizes release, handles deviations and provides corrective action. Require advance notification when a critical party changes. Business-registration evidence supports identity but does not replace technical qualification of the offered lot.

Plan logistics and receiving controls

Confirm dispatch location, carrier, shipping term, packaging configuration and realistic production, release and transit windows. Reject guarantees of customs clearance or misleading declarations. On receipt, document package condition, seals, product, strength, lot and quantity, then connect internal inventory to the supplier batch. Store according to the applicable approved specification and quarantine unexplained damage, label conflicts, quantity differences or excursions until a documented quality decision is completed.

Use actual performance for repeat-order approval

A controlled evaluation order should use the same specification and evidence expectations planned for wholesale scale. Assess document accuracy, packaging, delivery time, communication and corrective response. Update a supplier scorecard from observed performance rather than catalog breadth or claims. For every new lot, repeat the batch review and approve current documents before dispatch. Require notification before changes to material specification, manufacturing, testing, filling, labels, packaging or other buyer-approved conditions.

Related products and same-category guides

• Frag 17-23 10mg
• BPC-157 vs TB-500 Guide
• HPLC and MS Testing Guide

Frequently asked questions