AssayIndex
Neuroactive and cognitive peptides

Semax

Met-Glu-His-Phe-Pro-Gly-Pro · ACTH (4-7) PGP · C37H51N9O10S · monoisotopic 813.3541 Da. The index holds 160 assay reports on this compound across 25 batches from 13 suppliers.

160 reports25 batchesmedian 99.17 %index spec 98.5 %
Section 1

Analytical fingerprint

Hand-authored chemistry. These properties describe the substance and do not change when a record is added.

Semax carries a free N-terminal methionine, which is about the most oxidation-prone arrangement available, and the index's semax records show sulfoxide levels averaging 1.1 % area — the highest mean oxidation level of any compound tracked. That is mostly a storage artefact rather than a synthesis one: dry, cold, dark lots come in at 0.2–0.4 %. Semax is the index's standard example when explaining why an old COA does not describe the vial in your hand.

Molecular formula
C37H51N9O10S
Monoisotopic mass
813.3541Da
Average mass
813.93Da
Residues
7
Nominal retention (RG-2, 30 min)
7.06min
Retention window
0.25min
Counter-ion as usually shipped
acetate
Typical label claims
5 mg · 10 mg · 20 mg
Analytical difficulty (index scale)
0.85 — straightforward
Purity is a defined quantity
YES
Section 2

Representative chromatogram

Drawn from this page's own medians. Not a scan, not an illustration, and not any single report.

0379375861138015173 Semax7.06 min · 99.17 % 6.70 same trace · ×200 vertical expansion, baseline-corrected · main peak off-scale reporting threshold 0.05 % area 05101520253035 Retention time (min) Response (mAU)
Figure 1. A representative Semax trace on the index reference method RG-2, constructed from this page's own numbers: the main peak carries the index median purity of 99.17 % area at the nominal retention time of 7.06 min, and each impurity peak carries the median area the index has observed for that named species at its characteristic retention offset. It is not a scan of any single report — every individual record's own chromatogram is on its own page. The lower panel is the same trace at a stated vertical expansion, baseline-corrected, so the impurities are visible; the main peak runs off-scale there by design. Baseline noise is seeded from the compound slug.
Section 3

What the index has observed

Arithmetic over the 160 records the index holds. Aggregates on this page are computed over the records the index holds, which are not a random sample of the material on the market. Lots that get tested are lots someone chose to test. Read every figure here as a description of this dataset rather than as an estimate of a population.

Median purity 99.17% n=160
Interquartile range 0.98pp n=160
Minimum 97.80% n=160
Maximum 99.93% n=160
Pass rate vs spec 81.3% n=160
Median recovery vs claim 99.5% n=101
Median water 7.69% n=160
Median |mass error| 2.2ppm n=138
09182792.093.094.095.096.097.098.099.0100.092.00–92.25 %: n=092.25–92.50 %: n=092.50–92.75 %: n=092.75–93.00 %: n=093.00–93.25 %: n=093.25–93.50 %: n=093.50–93.75 %: n=093.75–94.00 %: n=094.00–94.25 %: n=094.25–94.50 %: n=094.50–94.75 %: n=094.75–95.00 %: n=095.00–95.25 %: n=095.25–95.50 %: n=095.50–95.75 %: n=095.75–96.00 %: n=096.00–96.25 %: n=096.25–96.50 %: n=096.50–96.75 %: n=096.75–97.00 %: n=097.00–97.25 %: n=097.25–97.50 %: n=097.50–97.75 %: n=097.75–98.00 %: n=498.00–98.25 %: n=1298.25–98.50 %: n=1498.50–98.75 %: n=1398.75–99.00 %: n=2199.00–99.25 %: n=2499.25–99.50 %: n=2399.50–99.75 %: n=2099.75–100.00 %: n=29median 99.17 Purity (% area) Reports
Figure 2. Purity distribution across all 160 Semax records. Dashed line is this compound's median (99.17 %); the solid vertical is the index acceptance specification for the neuroactive and cognitive peptides class (98.5 %). Domain is fixed at 92–100 % on every purity histogram on this site so that compounds can be compared by eye — a wide distribution here is a hard compound, a narrow one is an easy one, and neither is a statement about the suppliers.
Section 4

By supplier

Suppliers with fewer than two purity records on this compound are omitted from the figure rather than drawn as a line. The full table, including the thin cells, is on the by-supplier page.

97.698.098.598.999.399.7100.1WWBWWB: Q1 99.20, median 99.56, Q3 99.90, n=24n=24HomopeptideHomopeptide: Q1 99.44, median 99.69, Q3 99.93, n=23n=23GGPepsGGPeps: Q1 98.19, median 98.63, Q3 98.98, n=19n=19KPKP: Q1 98.89, median 99.26, Q3 99.71, n=18n=18TFCTFC: Q1 99.25, median 99.29, Q3 99.52, n=13outlier 98.74outlier 99.93outlier 99.93n=13WXTWXT: Q1 98.28, median 98.50, Q3 98.79, n=13n=13SSASSA: Q1 98.19, median 98.30, Q3 98.44, n=11outlier 98.84outlier 99.12n=11MKMMKM: Q1 98.50, median 98.61, Q3 99.19, n=11n=11ERPERP: Q1 99.57, median 99.81, Q3 99.87, n=9outlier 99.05n=9GL BiochemGL Biochem: Q1 98.72, median 98.90, Q3 99.01, n=9outlier 98.19outlier 99.57n=9JEEPJEEP: Q1 99.08, median 99.09, Q3 99.43, n=5outlier 98.53n=5HJHJ: Q1 99.06, median 99.13, Q3 99.19, n=4n=4 Purity (% area)
Figure 3. Semax purity by supplier, ordered by coverage. The vertical line is the index acceptance specification. Boxes that overlap are suppliers this dataset cannot separate, and most of them overlap.

Full per-supplier table with n= caveats →

Section 5

Characteristic impurities and degradants

The left three columns are authored chemistry — what this molecule characteristically carries and where it elutes. The right three are what the index has actually reported.

Named speciesΔRT (min, RG-2)Δ mass (Da)Seen inMedian % areaMax % area
des-Met (−131 Da)+0.20-131.04094%0.090.91
N-acetyl semax (+42 Da)+0.42+42.01193%0.130.94
Met1 sulfoxide (+16 Da)-0.36+15.99593%0.211.51
diketopiperazine (−18 Da)+0.16-18.01191%0.181.26

Degradation pathways

  • Met1 oxidation — an N-terminal methionine on a hygroscopic cake is a bad combination
  • diketopiperazine formation

Full impurity profile, with what each named species implies about the synthesis →

Section 7

Quarterly coverage

QuarterReportsMedian purityRange
2024-Q11599.3698.23–99.93
2024-Q21398.5098.09–99.17
2024-Q31098.9698.19–99.57
2024-Q4998.3097.99–99.12
2025-Q10n<3—
2025-Q2898.8598.18–99.21
2025-Q30n<3—
2025-Q41299.3898.85–99.93
2026-Q15899.5697.80–99.93
2026-Q23099.0998.30–99.93
2026-Q3599.1798.94–99.44

Quarter-by-quarter detail →

Section 8

Most recent records

The 25 most recent Semax records of 160.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-042368HJHJ-2603-V4363Nordanalyt2026-Q399.177.26106.3Supplier-supplied1MARGINAL
AX-2026-042367HJHJ-2603-V4363Kestrel2026-Q399.106.7893.9Supplier-supplied1MARGINAL
AX-2026-042260HomopeptideHOMO-2605-S1342Medutest2026-Q399.446.0692.4Laboratory-retained1FAIL
AX-2026-042370HJHJ-2603-V4363Janoshik2026-Q398.947.16104.0Supplier-supplied1MARGINAL
AX-2026-042369HJHJ-2603-V4363Janoshik2026-Q399.267.6795.0Supplier-supplied1MARGINAL
AX-2026-041947TFCTFC-2602-F4591Nordanalyt2026-Q299.298.9892.3Supplier-supplied0PASS
AX-2026-041940TFCTFC-2602-F4591Janoshik2026-Q299.068.3898.8Buyer-sourced0PASS
AX-2026-043141SSASSA-2604-L7628Kestrel2026-Q298.848.5893.2Supplier-supplied2MARGINAL
AX-2026-042903MKMMKM-2512-B2992Janoshik2026-Q298.616.8999.2Supplier-supplied1MARGINAL
AX-2026-043142SSASSA-2604-L7628VendorInvestigate2026-Q298.308.24—Buyer-sourced2FAIL
AX-2026-042656GGPepsGGPE-2602-Y8213Kestrel2026-Q298.995.3289.8Supplier-supplied2MARGINAL
AX-2026-042655GGPepsGGPE-2602-Y8213Janoshik2026-Q299.095.09106.4Supplier-supplied0PASS
AX-2026-042658GGPepsGGPE-2512-Y8309VendorInvestigate2026-Q298.837.19104.0Buyer-sourced0PASS
AX-2026-042902MKMMKM-2512-B2992PeptideMeter2026-Q299.357.26107.2Supplier-supplied2FAIL
AX-2026-041945TFCTFC-2602-F4591Nordanalyt2026-Q299.528.85—Supplier-supplied0PASS
AX-2026-041941TFCTFC-2602-F4591PeptideMeter2026-Q299.258.99—Laboratory-retained0PASS
AX-2026-042906MKMMKM-2512-B2992Janoshik2026-Q298.436.67—Buyer-sourced1FAIL
AX-2026-041948TFCTFC-2602-F4591PeptideMeter2026-Q299.288.46—Laboratory-retained0PASS
AX-2026-041950TFCTFC-2602-F4591Janoshik2026-Q299.278.59103.3Supplier-supplied0PASS
AX-2026-041943TFCTFC-2602-F4591Medutest2026-Q299.938.70106.0Supplier-supplied0PASS
AX-2026-041944TFCTFC-2602-F4591Nordanalyt2026-Q299.939.3791.7Supplier-supplied1MARGINAL
AX-2026-042904MKMMKM-2512-B2992Janoshik2026-Q298.537.1691.6Supplier-supplied1MARGINAL
AX-2026-042654GGPepsGGPE-2602-Y8213PeptideMeter2026-Q299.215.22102.5Supplier-supplied1MARGINAL
AX-2026-042900MKMMKM-2512-B2992PeptideMeter2026-Q298.397.12102.8Supplier-supplied1FAIL
AX-2026-042907MKMMKM-2512-B2992Kestrel2026-Q299.356.6190.8Supplier-supplied1MARGINAL