m.demir96/100
Declared figure not adjusted upward between certificate and commercial documentation. Peptide content 99.1%. No adverse observation.
QSC — Qingdao Sigma Chemical Co., Ltd.
Qingdao, CN. The index holds 350 assay reports across 66 batches and 28 compounds, contributed by 6 laboratories. Every figure below is computed from those records and from nothing else.
Where QSC sells
Qingdao Sigma Chemical Co., Ltd. sells from its own storefront. The link is marked nofollow and sponsored: it exists so the figures on this scorecard can be read against what the supplier itself publishes. The index is paid nothing for it and a link is not an assessment.
Visit QSC at qingdaosigma.com →
Every figure above describes lots the index has seen. It says nothing about the lot you are offered, and the only check that does is the one on the certificate against the vial.
Block 1
Identification
Business facts, held constant across the index and not derived from the data. The index sells nothing and takes no supplier payment for placement; the storefront link below is marked nofollow and sponsored so a record can be checked against the seller, and is not a recommendation.
- Legal name
- Qingdao Sigma Chemical Co., Ltd.
- Short code in this index
- QSC
- Also known as
- QSC · Sigma Chemical · QSC Peptides
- Domain
- qingdaosigma.com →
- City
- Qingdao
- Region
- Shandong
- Country
- CN
- Established
- not stated
- First record in index
- 22 Jan 2024
- Most recent record
- 05 Oct 2026
Block 1b
Dispatch and regional stock
Counted from the chain-of-custody line on this supplier's own records, which names the route each vial travelled to the laboratory, and from the on-record reviews below. The index has no sight of any supplier's warehouse network and publishes none.
Domestic-warehouse route
14.0%
n=350
Retail, shipped to the buyer
78.0%
n=350
Direct to the laboratory
2.0%
n=350
Median courier leg, direct despatch
8d
n=7
| Route to the laboratory | Records | Share |
|---|---|---|
| Domestic warehouse despatch | 49 | 14.0% |
| Retail purchase, shipped to the buyer | 226 | 64.6% |
| Retail purchase via a third-party forwarder | 47 | 13.4% |
| Supplier despatch direct to the laboratory | 7 | 2.0% |
| Laboratory retained-sample archive | 21 | 6.0% |
Every record here carries a chain-of-custody line and that line names the route the vial travelled. Of the 350 QSC records the index holds, 49 reached the contributing laboratory from a domestic warehouse rather than as a cross-border consignment, covering 16 of the 28 compounds QSC is represented by here — Tirzepatide, TB-500, Semaglutide, CJC-1295 (no DAC), GHRP-6, PT-141 (Bremelanotide) and 10 further compounds. Those are the QSC lines this index has actually seen arrive from regional stock, and they are a count of consignments rather than a stock listing: a line missing from them may simply never have been submitted for assay.
No contributor to this index has named a regional stock location for QSC. 49 of its records nevertheless arrived by a domestic-warehouse route, so stock is held somewhere; the index does not know where and will not guess.
The index measures nothing about lead time — it assays material, it does not buy it. What it has is QSC's own reviewers: 5 of the 26 on-record reviews state a quoted window and what happened against it, and 2 of them describe same-day dispatch. Where QSC despatched a sample direct to a laboratory, the courier leg ran a median 8 days across 7 such consignments — that is a transit time the index can see, and it is not the same thing as a lead time. The reviews are reproduced in full in Block 11.
Block 2
Headline statistics
Each figure carries the n it was computed from. The n= badge next to a statistic is the number of records it was computed from. Below n=8 the badge is amber. Below n=3 the statistic is suppressed and the individual values are shown instead.
Median purity
99.51%
n=350
Interquartile range
0.81pp
n=350
10th percentile
98.60%
n=350
Pass rate vs index spec
97.4%
n=350
Median recovery vs claim
97.4%
n=225
Median water
4.90%
n=350
Median |mass error|
2.5ppm
n=302
Records carrying a flag
36.3%
n=350
Block 3
Reproducibility across independent tests of one lot
Where the same physical lot was assayed more than once, the spread between those results is a property of the material and the fill, not of the market. It is the rarest and most informative statistic on this page, and it exists only for lots someone tested twice.
Median within-batch spread
0.61pp
n=45
Index median spread
0.67pp
n=28
Lots tested 3+ times
45
n=66
Across the 45 QSC lots in the index with three or more independent assays, the median spread between the highest and lowest purity result on one lot is 0.61 pp. Interpreting that number requires the laboratory repeatability figures: the best contributing laboratory here repeats to 0.16 pp and the worst to 0.34 pp, so a within-lot spread under about 0.5 pp is indistinguishable from measurement noise and a spread above 1 pp is a statement about the material.
Block 4
Supplier certificate against independent measurement
The supplier's own COA purity figure for a lot, minus the median of the index's independent observations of the same physical lot. Positive means the certificate reads higher than the measurement. Rule AX-R05 fires above 1.5 pp.
Median COA divergence
+0.00pp
n=66
Index median divergence
+0.06pp
n=28
Divergences in the supplier's favour
50%
n=66
Divergences beyond 1 pp
0%
n=66
Block 5
Provenance — where the tested material came from
Supplier-supplied samples are weaker evidence than independently purchased ones, because the supplier chose the vial. The index measures the size of that effect rather than assuming it.
Buyer-sourced median
99.51%
n=322
Supplier-supplied median
99.72%
n=7
Supplier-supplied share of records
2.0%
n=350
Block 6
Documentation completeness
The score is not an opinion about paperwork. Each component is the share of QSC batches in the index whose certificate carries that field, weighted as set out on the scoring rubric.
Documentation score
90/100
n=66
Index median score
85/100
n=28
| Certificate field | Batches carrying it | Rubric weight | |
|---|---|---|---|
| Purity figure stated | 100% | 25 points | |
| Analytical method stated (column, gradient, wavelength) | 80% | 25 points | |
| Peptide content stated | 70% | 20 points | |
| Endotoxin stated | 41% | 15 points | |
| Named impurities rather than a total | 67% | 15 points |
Block 7
Coverage by compound
The delta column is this supplier's median minus the index-wide median for the same compound, which is the only comparison worth making: comparing a supplier's aggregate against another supplier's aggregate compares their product mixes as much as their process control.
| Compound | Class | Reports | Median % | Index median % | Δ (pp) | Index spec | Pass % |
|---|---|---|---|---|---|---|---|
| Semaglutide | Incretin | 56 | 99.25 | 98.89 | +0.36 | 97.0 | 100 |
| Tirzepatide | Incretin | 50 | 99.38 | 98.55 | +0.83 | 97.0 | 100 |
| TB-500 | Tissue-repair | 48 | 99.80 | 99.53 | +0.27 | 98.5 | 100 |
| CJC-1295 (no DAC) | Growth-hormone | 39 | 99.03 | 99.09 | -0.06 | 98.0 | 90 |
| Retatrutide | Incretin | 28 | 99.03 | 98.37 | +0.66 | 96.5 | 100 |
| GHRP-6 | Growth-hormone | 17 | 99.77 | 99.54 | +0.23 | 99.0 | 100 |
| Melanotan II | Melanocortin-receptor | 13 | 99.82 | 99.42 | +0.40 | 98.5 | 100 |
| BPC-157 | Tissue-repair | 12 | 99.52 | 99.16 | +0.36 | 98.0 | 100 |
| Epitalon | Short | 12 | 99.91 | 99.56 | +0.35 | 99.0 | 100 |
| MK-677 (Ibutamoren mesylate) | Non-peptide | 11 | 99.74 | 99.49 | +0.25 | 98.5 | 100 |
| SS-31 (Elamipretide) | Metabolic | 9 | 98.40 | 99.53 | -1.13 | 98.5 | 44 |
| AOD-9604 | Metabolic | 7 n=7 | 99.70 | 99.29 | +0.41 | 98.0 | 100 |
| Enclomiphene citrate | Non-peptide | 6 n=6 | 99.79 | 99.44 | +0.34 | 98.5 | 100 |
| PT-141 (Bremelanotide) | Melanocortin-receptor | 5 n=5 | 99.55 | 99.38 | +0.17 | 98.5 | 100 |
| Kisspeptin-10 | Melanocortin-receptor | 5 n=5 | 99.49 | 99.28 | +0.21 | 98.5 | 100 |
| Pramlintide | Incretin | 4 n=4 | 99.44 | 99.10 | +0.34 | 97.5 | 100 |
| ARA-290 | Tissue-repair | 4 n=4 | 99.62 | 99.42 | +0.20 | 98.0 | 100 |
| Selank | Neuroactive | 3 n=3 | 99.93 | 99.59 | +0.34 | 99.0 | 100 |
| Ipamorelin | Growth-hormone | 3 n=3 | 99.60 | 99.47 | +0.13 | 99.0 | 100 |
| Survodutide | Incretin | 3 n=3 | 98.31 | 98.38 | -0.07 | 96.5 | 100 |
| MOTS-c | Metabolic | 3 n=3 | 99.93 | 99.13 | +0.80 | 98.0 | 100 |
| Liraglutide | Incretin | 2 n=2 | n<3 | 99.00 | — | 97.5 | 100 |
| Pinealon | Short | 2 n=2 | n<3 | 99.93 | — | 99.0 | 100 |
| CJC-1295 with DAC | Growth-hormone | 2 n=2 | n<3 | 98.95 | — | 97.5 | 100 |
| L-Glutathione (reduced) | Short | 2 n=2 | n<3 | 99.33 | — | 98.5 | 100 |
| IGF-1 LR3 | Growth-hormone | 2 n=2 | n<3 | 98.28 | — | 95.0 | 100 |
| Triptorelin | Hypothalamic | 1 n=1 | n<3 | 99.41 | — | 98.5 | 100 |
| Dihexa | Neuroactive | 1 n=1 | n<3 | 99.63 | — | 98.5 | 100 |
Full per-compound breakdown with distributions and caveats →
Block 8
Quarterly trend
Submission volume is not market share and a quarterly median is not a trend unless the compound mix held still. Both caveats apply to every row below.
Median purity by quarter
Quarters with fewer than two purity records are gaps in the line rather than zeroes.
Coverage growth
Records added per quarter. Growth here is index coverage, not supplier volume.
| Quarter | Batches | Reports | Median purity | Range | Flagged |
|---|---|---|---|---|---|
| 2024-Q1 | 4 | 22 | 99.73 | 99.28–99.93 | 11 |
| 2024-Q2 | 1 | 1 | n<3 | — | 0 |
| 2024-Q3 | 7 | 30 | 99.78 | 98.77–99.93 | 22 |
| 2024-Q4 | 4 | 22 | 99.06 | 98.18–99.93 | 4 |
| 2025-Q1 | 6 | 58 | 99.48 | 98.79–99.93 | 7 |
| 2025-Q2 | 3 | 19 | 99.77 | 98.76–99.93 | 14 |
| 2025-Q3 | 6 | 37 | 99.43 | 97.73–99.93 | 22 |
| 2025-Q4 | 11 | 41 | 99.65 | 98.04–99.93 | 17 |
| 2026-Q1 | 12 | 70 | 99.27 | 97.79–99.93 | 7 |
| 2026-Q2 | 9 | 38 | 99.70 | 98.84–99.93 | 14 |
| 2026-Q3 | 3 | 12 | 98.25 | 97.74–99.59 | 9 |
Block 9
Which laboratory produced these numbers
Laboratories disagree with each other by a measured amount. A supplier tested mostly by one laboratory carries that laboratory's offset in its aggregate, and the adjusted column removes it.
| Laboratory | Reports | Median purity | Lab bias (pp) | Bias-adjusted |
|---|---|---|---|---|
| Janoshik | 153 | 99.52 | +0.00 | 99.52 |
| PeptideMeter | 54 | 99.43 | -0.05 | 99.48 |
| Medutest | 48 | 99.59 | +0.08 | 99.52 |
| VendorInvestigate | 36 | 99.13 | -0.11 | 99.24 |
| Nordanalyt | 30 | 99.46 | +0.02 | 99.44 |
| Kestrel | 29 | 99.93 | +0.24 | 99.69 |
Bias figures are estimated from paired same-lot comparisons and are published with their confidence intervals on inter-lab agreement.
Block 10
What this data does and does not show
Block 11
On-the-record reviews 26
Reviews are signed statements from index contributors about their own testing of this supplier's material. They are opinions attached to evidence, and they are not used in any statistic on this page.
97.0/ 100547 ratings across the index network
v.iyer95/100
Two lots ordered deliberately for comparison. Reported purities 0.1 points apart. Figures as reported by the named service. Not reproduced by the index.
c.ilunga98/100
Transit 4 days from stock held in the United States against a quoted 4. Customs documentation correct at first presentation. Catalogue availability matched the published catalogue.
n.adeyemi97/100
Packing: labels printed rather than handwritten, lot and date legible. Regional stock held for the lines concerned. Subsequent orders placed with the same supplier.
d.sorensen97/100
Cross-check: PeptideMeter and Medutest, same lot, agreement to 0.1 points. Both agree with the declared figure. Evidence base adequate for a rating on this criterion.
me.ramos96/100
Published stock status matched availability. Same-day dispatch. Medutest report held on file, figures match published.
n.girard99/100
Fill uniformity: 11 units weighed against declared fill, all within 2%. Supplementary certificate produced without demur. n=1, declared as n=1.
z.zamora98/100
Documentation complete at first issue. No supplementary request raised. Cost per assayed milligram sits with the documentation supplied, and the certificate carries every field the index scores. Independent verification of individual lots still required.
s.falk98/100
11 orders, 8 months. No substitution, no reformulation, no post-payment unavailability.
r.ferreira97/100
Orthogonal identity present: mass spectrometry alongside the chromatographic determination. No adverse observation.
b.kuipers97/100
Line quoted that three comparable suppliers declined to quote. Material returned within specification. Gradient and column chemistry stated.
b.cardoso98/100
Consistency: 9 lots, purity band under 1.0 points wide. Janoshik report held on file, figures match published.
la.boateng95/100
Batch record supplied in full on request, attached rather than summarised. Supplementary certificate produced without demur.
c.ekstrom96/100
Purity by RP-HPLC, wavelength stated, stability-indicating method named. Determination is reproducible from the certificate alone. Declared and independent figures differ by less than repeatability.
y.kuusela100/100
Same-day dispatch against a next-day quote. Identity confirmed by two orthogonal methods.
h.sobczak98/100
Release signed and dated, named individual. Regional stock held for the lines concerned. Figures as reported by the named service. Not reproduced by the index.
f.achebe95/100
Reconstitution of glutathione 600 mg: clear on contact, no haze, no particulate. Gradient and column chemistry stated.
fa.sjoberg96/100
Lot QSC-25-647 submitted to PeptideMeter. Declared 98.5%, reported 98.9%. Delta inside method repeatability. PeptideMeter report held on file, figures match published. Subsequent orders placed with the same supplier.
j.serrano100/100
Four orders, four lot-specific certificates, each attached at despatch rather than on request. Evidence base adequate for a rating on this criterion.
ay.lundgren96/100
Cold chain intact. Phase-change pack solid at arrival, day 4. Contributor declares no interest beyond the transaction.
k.correia98/100
Blind submission of tirzepatide 15 mg to Janoshik, origin withheld. 97.5% against 97.5% declared. Catalogue availability matched the published catalogue.
ig.beaulieu97/100
Supplementary certificate for a lot released 6 months earlier retrieved from supplier records on request. Regional stock held for the lines concerned. Submitted to the index in full.
r.ogunleye96/100
Related-substances table itemised by impurity with assigned retention times. Not aggregated. Nothing unsecured in the consignment. Subsequent orders placed with the same supplier.
t.palacios95/100
Repeat determination at 20 months: 98.7%. Original: 98.7%. No drift detected in this sample. No adverse observation.
s.mensah99/100
Custom synthesis delivered 2 days inside the quoted schedule at the specified purity. Documentation practice, not a single purity figure, is the substance here.
r.cabrera98/100
Certificate carries an itemised related-substances table. Complete against the index minimum data set at first issue. Quote itemised by lot size, honoured as issued, and reconciled against the packing list on arrival. n=1, declared as n=1.
Block 12
Most recent records
Block 13
Contributor annotations on QSC records 787
Annotations are this index's only discussion surface: signed technical comments attached to a specific record by a named contributor. They are not moderated for agreement with the index's own arithmetic. The most recent on QSC material are below, each linked to the record it sits on.
A chromatogram bears on endotoxin not at all. Purity, identity, content and water can all be excellent on material carrying a substantial burden, and nothing on this page would show it.
Retail certificates in this index carry a retest date more often than they used to. It is the field that turns a release figure into a statement about the material over time.
Two retail purchases of the same lot from different buyers are genuinely independent. Two aliquots of one purchase are not, and the index does not treat them as such.
Identity confirmed and purity at 97.96 %. The two answer different questions — what it is, and how much else is in it — and a record carrying both is the version worth citing.
What this record does establish is on the page and it is substantial. What it does not establish is listed under the provenance block rather than left for the reader to infer.
Where the nearest species is a diastereomer of CJC-1295 (no DAC), resolution is the only thing that separates them at all — no mass measurement will. The compound fingerprint states what is achievable and on what method.
Purity 98.36 % describes what fraction of the eluted material is the target. Content describes what fraction of the cake is peptide at all. Both are on this record and neither substitutes for the other.
Resolution to the nearest named impurity is reported on this record with no verdict attached, which is the correct handling. A threshold on that figure would penalise compounds for their own impurity profiles.
Every annotation the index holds on QSC material sits on its own record; the full set is reachable from the record listing and from each contributor's page. To read them against what QSC itself publishes, open qingdaosigma.com → alongside.
Block 14
Where to buy QSC
Qingdao Sigma Chemical Co., Ltd. sells direct from qingdaosigma.com. Everything on this page describes lots the index has already seen; the certificate that matters is the one that arrives with the vial you order, and the lot code on it should match the vial. Ask for the lot-specific document rather than the batch-level summary, and ask for the integration report if you intend to reconcile the figure yourself.
Go to the QSC store at qingdaosigma.com →
Marked nofollow and sponsored. The index is paid nothing for it, takes no commission, and a link is not an assessment. Research compounds. Not medical advice. Nothing on this site is a safety assessment and nothing on it is approved for human use.