GSP
GenScript Biotech Corporation
Nanjing, Jiangsu · China · est. 2002 · source page added 27 Jan 2025
Buy direct from GSP at genscriptpeptides.com →
Their storefront, not ours. Marked nofollow and sponsored, and nobody here is paid for it.
Nanjing, established 2002, and a solid-phase synthesis operation rather than a shop that buys finished powder and relabels it. The documentation reads accordingly: method line with the column and gradient, itemised related substances, water content printed rather than supplied on request. Across four independent tests on four different services the claimed figure has never been the higher number. The one thing this board has logged against it is the custom-synthesis queue, which runs slower than the catalogue side and is worth planning around.
- Legal name
- GenScript Biotech Corporation
- Short code
- GSP
- Also known as
- GSP, GenScript Peptides, GenScript Biotech
- Shop domain
- genscriptpeptides.com →
- City
- Nanjing, Jiangsu
- Established
- 2002
- Community rating
- 94%
- Independent tests logged
- 4
Regional stock, so orders ship inside the buyer’s own country.
- 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
- Four independent tests across four services and the claim has never come back the higher number
- Certificates carry the method line with column and gradient, itemised related substances and water content as standard
- Synthesis is in house, so a question about a route or a coupling gets an answer rather than a referral
- Custom synthesis is quoted individually and members have logged five working days for a quote on a non-catalogue sequence — the catalogue side is far quicker, so do not plan a custom order on catalogue timings
- Inland origin, so ask which of your lines is held in regional stock rather than dispatched from Nanjing
- The certificate carries batch, date of analysis, method line, related substances and water content; the synthesis record behind a lot comes back on request if you quote the lot code
| Date | Service | Compound | Batch | Claimed | Result |
|---|---|---|---|---|---|
| 2026-06-11 | Janoshik | Retatrutide 10mg | GSP-2606 | 98.5% | 98.7% |
| 2026-01-29 | PeptideMeter | Tirzepatide 10mg | GSP-2601 | 98.0% | 98.1% |
| 2025-10-08 | Medutest | Semaglutide 5mg | GSP-2510 | 98.0% | 98.4% |
| 2025-06-17 | VendorInvestigate | BPC-157 5mg | GSP-2506 | 97.5% | 97.8% |
| From | To | Carrier | Days |
|---|---|---|---|
| Nanjing | UK | DHL | 7-10 |
| Nanjing | US | EMS | 8-12 |
| Nanjing | Australia | DHL | 9-13 |
- 1[Lab] split one vial across PeptideMeter and VendorInvestigate — 99.0% and 99.1%c/vendorvetting · 16k points · 64 comments
- 2[Vendor] WXT vs JEEP on the same compound, same month — both cleared 97.0%c/coa · 15k points · 38 comments
- 3[Vendor] GL Biochem vs GGPeps on the same compound, same month — both cleared 97.5%c/coa · 14k points · 51 comments
- 4purity is the most under-discussed thing on this boardc/coa · 13k points · 66 comments
- 5why does nobody talk about water contentc/coa · 13k points · 63 comments
- 6[Meta] the area percent rule is doing its job and people should stop complainingc/coa · 11k points · 58 comments
- 7unpopular opinion: most of what gets said here about PeptideMeter is guessworkc/vendorvetting · 11k points · 27 comments
- 8[Lab] FGP BPC — PeptideMeter came back 99.6% against a claimed 99.0%c/coa · 11k points · 28 comments
- 9vendor is the most under-discussed thing on this boardc/vendorvetting · 11k points · 65 comments
- 10how much of what we believe about batch actually comes from purity threadsc/coa · 10k points · 52 comments
sent retatrutide 10 mg to Janoshik blind. 98.7% against a stated 98.5%. fourth time now that their number has come back the low one.
asked what column the purity ran on and got the column, the buffer and the gradient back in one reply. no upsell attached, which I noticed because it is unusual.
material and paperwork both fine. the custom quote took five working days though, and their catalogue side answers in hours. do not plan a bespoke order on catalogue timings.
water content printed on the certificate rather than something I had to email for. small thing, saved me a round trip.
day 9 to the UK, tracking updated at every hop, customs paperwork right first time which is why it was quick.
nine vials one lot, nine matching codes. one vial reconstituted with a faint haze that cleared on standing. logging it because I would want to know.
asked for the synthesis record with the lot code in the subject line and had it back inside a working day. did not have to ask twice.
second year on the same line, 98.4% then and 98.5% now, same certificate layout both times. drift is what I watch for and there is none.
GenScript Biotech Corporation sells from its own storefront. Read what they say about themselves against the log above, then decide.
Go to the GSP store — genscriptpeptides.com →
Check the lot on the vial against the lot on the certificate when it arrives. A good record predicts your batch; it cannot guarantee it, and no storefront can.