Qingdao Sigma Chemical (revision 38)

Qingdao Sigma Chemical Co., Ltd. (trading as QSC; qingdaosigma.com) is a research-peptide supplier based in Qingdao, Shandong, China, described in available sources as operating from 2017 and distributing research peptides through a warehouse network, with third-party testing reported on part of its range.^[1][2]

The organisation is one of twenty covered on PeptidePedia under Project:Vendor notability. Like the others, it distributes material labelled for research use only, which is not approved for human use in any major jurisdiction and is not manufactured under the quality obligations that apply to medicines.^[3]

This article describes what is verifiable. Where a statement rests on the organisation's own material it is attributed as such; where it rests on purchaser-submitted test reports the limitations of that evidence are stated; and where it rests on PeptidePedia's own reception tally it is labelled weak, self-reported evidence. Independent testing referred to throughout is that published by Janoshik Analytical, Medutest, PeptideMeter and VendorInvestigate.^[4]

Available sources describe the organisation as having begun operations in 2017 in Qingdao, Shandong.^[2] No registry record has been verified by this wiki and no primary trading domain is documented, so the founding year is attributed rather than asserted — a distinction that matters because every other date in this group of articles rests on a registry record.^[1]

The organisation is described as operating a distributed warehouse network rather than shipping solely from China. Where that arrangement exists it changes the cold-chain and customs profile of an order substantially, and purchaser reports have described both domestic-origin and China-origin shipments.^[5]

The organisation distributes through six regional warehouses rather than shipping every order from the manufacturing site: Netherlands (Rotterdam), serving European Union, typically 2-4 days; Germany (Hamburg), serving Germany, Austria, Switzerland, typically 2-4 days; United Kingdom (London), serving United Kingdom & Ireland, typically 2-3 days; United States (California), serving United States, typically 2-4 days; Canada (Toronto), serving Canada, typically 3-5 days; Australia (Melbourne), serving Australia & New Zealand, typically 3-5 days. Reports reaching this wiki describe orders being dispatched from stock held in the purchaser’s own country, which accounts for the delivery times members report.

Purchaser reports describe vialled lyophilised material with a batch certificate. Certificate content in the submitted set has been thin relative to comparators — purity and appearance, rarely a water figure and rarely a method.^[5][6]

Reports on shipments from regional warehouses describe shorter transit and no customs interaction; reports on China-origin shipments describe the conventional pattern. Which route an order takes has not been predictable from the available reports.^[5]

The catalogue is narrower than most covered here and the documentation thinner. Both are stated as observations from the submitted set rather than as characterisations of the organisation.^[5]

Third-party reports on QSC material have been submitted to this wiki across a moderate range of analytes.^[5] Reported area percent figures have been more dispersed than for the better-documented entities, with a visible proportion below the high-nineties cluster that characterises most of this group.

As with the Wuhan entity, dispersion is a property of the reports and the interpretation is limited by self-selection.^[5] The additional limitation specific to this organisation is the absence of method disclosure on most accompanying certificates: without a stated method, a disagreement between a certificate and an independent report cannot be attributed either to the material or to the separation, so the dispersion is uninterpretable in a further respect.^[6]

The PeptidePedia tally records 571 self-reported submissions to July 2026 — among the lowest of the supplier articles. Recurring complaints concern documentation depth, variance between orders, and unpredictability of shipping origin; recurring positive themes are price and, where a regional warehouse was used, delivery speed.^[4] Self-selected; reception rather than quality.^[4]

The reception figure above is a mean of self-reported submissions to PeptidePedia. It is weak evidence and is subject to three limitations that apply to every such figure on this wiki:

• Self-selection. People who submit are not a sample of purchasers. Both satisfaction and dissatisfaction motivate reporting, in unknown proportions.
• It measures reception, not quality. Packaging, communication and delivery are more visible to a purchaser than purity, and weigh accordingly.
• It is not comparable across communities. Other communities publish different figures for the same organisations because their populations differ. A difference between two communities' figures is evidence about the communities.^[4]

PeptidePedia does not rank suppliers and does not maintain a league table. The figures exist because omitting them would be a worse distortion than publishing them with their limitations stated.^[4]

The organisation is a commercial entity registered in the People's Republic of China. Nothing in the available record indicates a manufacturing authorisation, marketing authorisation or pharmacopoeial registration in any jurisdiction, and none should be inferred from a registered business scope, which is a licensing fact and not a quality assurance.^[1]

Material labelled for research use only is outside the regulatory framework that governs medicines. Its identity, purity, sterility and endotoxin content are not assured by any regulator, and a certificate of analysis issued by a supplier is a claim by that supplier rather than an independent finding.^[3][6]

• Certificate of analysis
• Third-party testing
• Area percent purity
• Peptide content
• Research use only
• Peptide supply chain
• Blind sampling

• Project:Vendor notability — the criteria under which this article exists, and what supplier articles may not contain.
• Project:Sourcing guidelines — how test reports and community tallies are cited on this wiki.