AssayIndex
Short bioregulator peptides

L-Carnosine

β-alanyl-L-histidine · C9H14N4O3 · monoisotopic 226.1066 Da. The index holds 29 assay reports on this compound across 5 batches from 5 suppliers.

29 reports5 batchesmedian 99.07 %index spec 99.0 %
Section 1

Analytical fingerprint

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

Carnosine is a dipeptide sold in gram quantities and the index tracks it mainly as a contrast case: at 3.72 min on C18 the compound is barely retained and the appropriate method is HILIC or ion-pair chromatography with a copper-complexation or OPA-derivatisation detection scheme. Anserine at +14 Da is the diagnostic natural-source contaminant and its presence indicates animal-tissue extraction rather than synthesis, which is a provenance finding the index reports on the batch page.

Molecular formula
C9H14N4O3
Monoisotopic mass
226.1066Da
Average mass
226.23Da
Residues
2
Nominal retention (RG-2, 30 min)
3.72min
Retention window
0.20min
Counter-ion as usually shipped
none expected
Typical label claims
500 mg · 1000 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.

07192143832157528767 L-Carnosine3.72 min · 99.07 % 3.66 same trace · ×100 vertical expansion, baseline-corrected · main peak off-scale reporting threshold 0.05 % area 05101520253035 Retention time (min) Response (mAU)
Figure 1. A representative L-Carnosine trace on the index reference method RG-2, constructed from this page's own numbers: the main peak carries the index median purity of 99.07 % area at the nominal retention time of 3.72 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 29 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 99.07% n=29
Interquartile range 1.41pp n=29
Minimum 97.64% n=29
Maximum 99.93% n=29
Pass rate vs spec 62.1% n=29
Median recovery vs claim 96.8% n=18
Median water 8.23% n=29
Median |mass error| 3.4ppm n=21
036992.093.094.095.096.097.098.099.0100.092.00–92.25 %: 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=197.75–98.00 %: n=098.00–98.25 %: n=598.25–98.50 %: n=298.50–98.75 %: n=198.75–99.00 %: n=299.00–99.25 %: n=499.25–99.50 %: n=399.50–99.75 %: n=299.75–100.00 %: n=9median 99.07 Purity (% area) Reports
Figure 2. Purity distribution across all 29 L-Carnosine records. Dashed line is this compound's median (99.07 %); the solid vertical is the index acceptance specification for the short bioregulator peptides class (99.0 %). 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.

97.597.998.398.899.299.7100.1HomopeptideHomopeptide: Q1 99.13, median 99.47, Q3 99.93, n=10n=10CPCCPC: Q1 98.05, median 98.24, Q3 98.53, n=9n=9FGPFGP: Q1 99.81, median 99.88, Q3 99.93, n=6outlier 99.57n=6SSASSA: Q1 98.31, median 98.42, Q3 98.86, n=3n=3 Purity (% area)
Figure 3. L-Carnosine 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
free histidine (−71 Da)-0.16-71.03793%0.181.11
anserine (methylcarnosine, +14 Da)+0.12+14.01690%0.110.50
β-alanine (−137 Da)-0.22-137.05983%0.180.53
D-carnosine epimer-0.06mass-identical79%0.360.99

Degradation pathways

  • hydrolysis by residual carnosinase activity in impure aqueous media
  • racemisation under heat

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

Section 7

Quarterly coverage

QuarterReportsMedian purityRange
2024-Q10n<3—
2024-Q21099.4798.99–99.93
2024-Q30n<3—
2024-Q40n<3—
2025-Q1699.8899.57–99.93
2025-Q2398.4298.19–99.30
2025-Q30n<3—
2025-Q40n<3—
2026-Q10n<3—
2026-Q21n<3—
2026-Q3998.2497.64–99.07

Quarter-by-quarter detail →

Section 8

Most recent records

The 25 most recent L-Carnosine records of 29.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-043283CPCCPC-2603-G1651Medutest2026-Q398.1010.1291.8Supplier-supplied1FAIL
AX-2026-043289CPCCPC-2603-G1651Janoshik2026-Q398.0110.52—Buyer-sourced1FAIL
AX-2026-043287CPCCPC-2603-G1651Janoshik2026-Q398.359.8993.2Supplier-supplied2FAIL
AX-2026-043286CPCCPC-2603-G1651Janoshik2026-Q398.5310.02—Supplier-supplied1FAIL
AX-2026-043285CPCCPC-2603-G1651Janoshik2026-Q398.0510.42—Supplier-supplied1FAIL
AX-2026-043288CPCCPC-2603-G1651PeptideMeter2026-Q399.039.94105.1Supplier-supplied1MARGINAL
AX-2026-043281CPCCPC-2603-G1651Nordanalyt2026-Q398.2410.17—Supplier-supplied1FAIL
AX-2026-043282CPCCPC-2603-G1651VendorInvestigate2026-Q397.6410.07—Buyer-sourced1FAIL
AX-2026-043284CPCCPC-2603-G1651Janoshik2026-Q399.0710.05100.3Supplier-supplied1MARGINAL
AX-2026-043188GL BiochemGLBI-2512-S8438Janoshik2026-Q298.779.2191.9Supplier-supplied2FAIL
AX-2025-020620SSASSA-2504-T7815VendorInvestigate2025-Q298.196.2397.2Buyer-sourced1FAIL
AX-2025-020619SSASSA-2504-T7815Nordanalyt2025-Q298.426.3993.7Buyer-sourced2FAIL
AX-2025-020621SSASSA-2504-T7815PeptideMeter2025-Q299.307.1993.7Supplier-supplied2MARGINAL
AX-2025-018937FGPFGP-2501-G1375Nordanalyt2025-Q199.578.41—Supplier-supplied1MARGINAL
AX-2025-018939FGPFGP-2501-G1375Janoshik2025-Q199.937.89—Supplier-supplied0PASS
AX-2025-018942FGPFGP-2501-G1375Nordanalyt2025-Q199.808.3096.4Supplier-supplied1FAIL
AX-2025-018940FGPFGP-2501-G1375Janoshik2025-Q199.938.38—Supplier-supplied0PASS
AX-2025-018938FGPFGP-2501-G1375Janoshik2025-Q199.938.2390.2Supplier-supplied0PASS
AX-2025-018941FGPFGP-2501-G1375Janoshik2025-Q199.838.55104.5Supplier-supplied0PASS
AX-2024-004804HomopeptideHOMO-2405-P1520Kestrel2024-Q299.435.3689.7Supplier-supplied2MARGINAL
AX-2024-004803HomopeptideHOMO-2405-P1520Medutest2024-Q299.936.6598.8Supplier-supplied0PASS
AX-2024-004806HomopeptideHOMO-2405-P1520VendorInvestigate2024-Q298.995.9897.1Buyer-sourced1FAIL
AX-2024-004805HomopeptideHOMO-2405-P1520PeptideMeter2024-Q299.026.1690.0Supplier-supplied1MARGINAL
AX-2024-004798HomopeptideHOMO-2405-P1520PeptideMeter2024-Q299.936.4599.7Supplier-supplied1MARGINAL
AX-2024-004799HomopeptideHOMO-2405-P1520Janoshik2024-Q299.526.22—Supplier-supplied1MARGINAL