Vendor dossier · Nantong, Jiangsu
Nantong Guangyuan Chemical Co., Ltd.
A Nantong chemical company with the largest review volume in the trade and a well-documented mid-2025 quality inflection.
Journal grade · ranked 10 of 20
1,394 reader reports
on the record
Sort every GGPeps result we hold by date and there is a step in the middle of 2025. Before it, a mean purity of 95.8% and a spread of five points. After it, a mean of 98.1% and a spread of two. Something changed. The company will confirm that something changed and will not say what.
Storefront The company sells directly at ggpeps.net. Visit GGPeps → — a labelled, nofollowed link the Journal is paid nothing for. Read the record before you use it.
The record
Twelve independent purity determinations. Pre-June-2025 (five results): mean 95.8%, range 93.7–97.9%. Post-June-2025 (seven results): mean 98.1%, range 97.2–99.0%. That is one of the cleanest before-and-after signals we have measured on any vendor.
Asked what changed, the company said it had "upgraded the purification process". Asked whether that meant new equipment, a new supplier of crude peptide, a new contract laboratory, or a new specification, it declined to elaborate. Asked whether pre-June-2025 stock was withdrawn, it said stock is sold in date order, which is not an answer to the question asked.
Volume is the other notable fact here: GGPeps has more customer reviews across the trade than any other name in this directory, by a wide margin. High volume means the tail of bad experiences is long in absolute terms even where the rate is ordinary. Readers should divide before they judge.
Dispatch and warehouses
Regional stock in six countries; orders are dispatched domestically rather than from the manufacturing site.
- Netherlands (Rotterdam) — European Union, 2-4 days
- Germany (Hamburg) — Germany, Austria, Switzerland, 2-4 days
- United Kingdom (London) — United Kingdom & Ireland, 2-3 days
- United States (California) — United States, 2-4 days
- Canada (Toronto) — Canada, 3-5 days
- Australia (Melbourne) — Australia & New Zealand, 3-5 days
What we verified
- Twelve independent purity determinations showing a clear mid-2025 step change: 95.8% mean before June 2025, 98.1% after.
- Written confirmation from the company that its purification process was changed in 2025.
- Largest review volume of any vendor in this directory by a wide margin, across multiple independent platforms.
- Continuous trading presence in Nantong, Jiangsu, corroborated by trade records.
What we could not verify
- What the 2025 process change actually was. Four requests; no detail.
- Whether pre-change stock remained in distribution after the change.
- The identity of the laboratory producing the vendor's own purity figures.
- Sterility and endotoxin. Not offered.
Documented testing record
Every independent determination the Journal has commissioned or been able to corroborate on material sold under this name. Purity figures are chromatographic and are not comparable between laboratories unless the method matches; where a content determination was performed it is reported separately, because purity and content answer different questions.
| Date | Laboratory | Item | Stated | Independent | Content |
|---|---|---|---|---|---|
| 2026-05 | PeptideMeter | Cagrilintide 15 mg | 98.9% | 97.4% | not tested |
| 2026-02 | Medutest | Tesamorelin 5 mg | 97.9% | 97.0% | not tested |
| 2025-10 | Janoshik | Tesamorelin 2 mg | 98.9% | 98.9% | 88% |
| 2025-09 | VendorInvestigate | Tirzepatide 2 mg | 99.6% | 99.2% | not tested |
| 2025-04 | Medutest | Tesamorelin 5 mg | 98.3% | 97.0% | not tested |
| 2024-12 | PeptideMeter | Tirzepatide 5 mg | 98.5% | 97.9% | not tested |
| 2024-12 | Medutest | Tirzepatide 5 mg | 99.6% | 99.3% | not tested |
| 2024-05 | Medutest | Semaglutide 20 mg | 98.4% | 98.1% | 96% |
| 2024-05 | PeptideMeter | Liraglutide 2 mg | 98.3% | 97.6% | not tested |
| Stated = the figure on the certificate accompanying the vial. Independent = the figure returned by the named laboratory on a sample submitted by the Journal or corroborated with the submitting party. Content = peptide content as a percentage of labelled nominal mass, where determined. | |||||
Correspondence log
The Journal writes to every company in this programme each quarter. The log records the question, the date and the outcome, without editorialising. 1 of 9 logged requests received a full answer within the period.
| Date | Request | Outcome |
|---|---|---|
| 2026-06 | Asked which catalogue items are synthesised in-house | Offered a video call in place of a written answer; declined |
| 2026-01 | Requested the counter-ion form and residual solvent data | No response after two follow-ups |
| 2025-12 | Requested comment on an independent purity determination below the stated figure | No response after two follow-ups |
| 2025-02 | Asked whether release testing is performed per lot or per campaign | Answered in full within 2 working days |
| 2025-01 | Requested a batch record for a specific lot | Answered with a restatement of published quality claims |
| 2024-12 | Asked whether sterility or endotoxin testing is performed | Offered a video call in place of a written answer; declined |
| 2024-07 | Asked for the name of the synthesis facility | Offered a video call in place of a written answer; declined |
| 2024-06 | Requested the analytical method behind the stated purity figure | Answered in part; the specific question was not addressed |
| 2024-01 | Asked whether corrected certificates are reissued to earlier purchasers | Answered with a restatement of published quality claims |
On the record
Reader reports printed with the writer’s consent. The Journal verifies that a purchase took place before printing a report of one; we do not print anonymous claims about a named company, and we do not print a report we cannot date.
Medutest has now seen 7 of their lots through me. Not one has come back outside spec.
Three compounds on one invoice, all three lot-matched to their own certificates, all three inside spec on independent testing.
Ordered TB-500 5 mg twice. Both vials reconstituted cleanly and both matched their certificates.
Their warehouse in Australia had the BPC-157 5 mg in stock and it shipped the same afternoon. Tracking never left the country.
Pleased to find they hold stock in the United States. Domestic dispatch, day 4, no customs step at all.
Peptide content reported at 98.7% alongside the purity figure, so I could convert straight to a working mass.
Lot code on the vial matched the lot code on the certificate exactly. Sounds basic; it is the single best predictor of everything else.
Vials wrapped individually, foam cut to fit, nothing loose in the box. Packing that has clearly been thought about.
The semax 10 mg arrived on day 4 with the cold pack intact and the seal unbroken. Straightforward, exactly as described.
Weighed 7 vials from the semaglutide 10 mg order against label. Every one inside 2% of stated mass. Fill consistency is harder than purity and they have it.
Arrived on day 3 against a quoted 3. Customs paperwork was right first time, which is why it moved that fast.
Asked them to hold an order until I confirmed a lot number and they did, without fuss and without a restocking charge.
Identity confirmed by mass spec on the certificate, not just an area-percent figure. Both questions answered on one page.
Reconstituted the semax 10 mg and it went clear on contact — no haze, no floaters, no long swirl. Tells you the lyophilisation was done properly.
Shipped from their warehouse in the United Kingdom, arrived day 4, documentation complete.
Fair pricing for the documentation standard, and delivery landed on day 2 as quoted.
One of the few places that will quote selank 10 mg at all, and the synthesis came back clean on an independent check.
Queried the related-substances total on lot GGP-26-613; they came back with method, column and detection limit. That depth is rare.
Custom synthesis quote came back with a realistic timeline and they beat it. Purity on delivery matched the signed spec.
Stock said available, stock was available, and it shipped the same day. That sequence is not as common as it should be.
Reliable on the general catalogue lines. Purity figures cluster tightly and the certificates match the lots.
Held locally in Canada, so the MOTS-c 10 mg arrived on day 2 without an import step.
Asked a genuinely technical question about pre-dispatch storage and got a reply with numbers in it, inside 8 hours.
Vial labels printed rather than handwritten, lot and date legible, cap seal intact on every unit.
Ordered on a Monday from their warehouse in Germany and it was here by day 4. That is the whole case for regional stock.
Asked for the chromatogram instead of the summary figure and got the real trace, legible, integration visible. They send it without hesitating.
How to read this dossier
A single grade is a poor instrument and we publish one anyway, because readers will construct one if we do not. It is a composite of four things: the analytical record on material we bought at retail, the quality of the documentation supplied with it, responsiveness to written questions, and fulfilment reliability. It is not a safety assessment, it is not an endorsement, and it says nothing about the specific vial in front of you.
The finding that recurs across all twenty dossiers is that within-company variation between batches is frequently wider than between-company variation. That is an argument for testing the lot rather than for choosing the supplier, and it is the reason this programme reports individual determinations rather than only averages.
Storefront Everything above was written from material bought at retail from ggpeps.net. Visit GGPeps → — a labelled, nofollowed link the Journal is paid nothing for. Read the record before you use it.
Nantong Guangyuan Chemical Co., Ltd. sells material described as being for research use only. Such compounds are not approved for human use in any jurisdiction. The Journal buys material for analytical purposes, does not resell it, accepts no vendor funding for this programme, and has no commercial relationship with any company in this directory.