AssayIndex
Incretin analogues and co-agonists

Retatrutide

LY3437943 · GGG tri-agonist · C221H342N46O68 · monoisotopic 4728.4871 Da. The index holds 492 assay reports on this compound across 74 batches from 23 suppliers.

492 reports74 batchesmedian 98.37 %index spec 96.5 %
Section 1

Analytical fingerprint

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

Retatrutide has the widest purity spread of any high-volume compound in the index (IQR 1.4 pp against 0.7 pp for semaglutide), and that is a real synthesis problem rather than an assay problem: three separate Aib positions and a long lipid tail make the crude mixture complex, and preparative resolution of the [D-Aib2] diastereomer is incomplete in most commercial lots. Retention is late at 20.7 min. The most useful single diagnostic is the ratio of the 0.58 min post-peak to the main peak — a C18 diacid regioisomer that rises when the acylation step is run hot. Lots carrying that regioisomer above 0.8 % area are worth reading alongside the appearance and clarity fields on the same record; the index publishes both and asserts no association between them. Base peak [M+4H]4+ at m/z 1183.13.

Molecular formula
C221H342N46O68
Monoisotopic mass
4728.4871Da
Average mass
4731.36Da
Residues
39
Nominal retention (RG-2, 30 min)
20.71min
Retention window
0.50min
Counter-ion as usually shipped
TFA
Typical label claims
5 mg · 10 mg · 12 mg · 15 mg · 20 mg · 30 mg
Analytical difficulty (index scale)
1.55 — hard
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.

01283256638485131 Retatrutide20.71 min · 98.37 % 20.4918.7924.8323.12 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 Retatrutide trace on the index reference method RG-2, constructed from this page's own numbers: the main peak carries the index median purity of 98.37 % area at the nominal retention time of 20.71 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 492 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 98.37% n=492
Interquartile range 0.86pp n=492
Minimum 95.81% n=492
Maximum 99.93% n=492
Pass rate vs spec 98.8% n=492
Median recovery vs claim 99.4% n=272
Median water 4.42% n=492
Median |mass error| 2.5ppm n=406
023466992.093.094.095.096.097.098.099.0100.092.00–92.25 %: 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=196.00–96.25 %: n=196.25–96.50 %: n=496.50–96.75 %: n=596.75–97.00 %: n=797.00–97.25 %: n=997.25–97.50 %: n=1597.50–97.75 %: n=2597.75–98.00 %: n=6598.00–98.25 %: n=6798.25–98.50 %: n=8098.50–98.75 %: n=7298.75–99.00 %: n=5299.00–99.25 %: n=4599.25–99.50 %: n=2299.50–99.75 %: n=1299.75–100.00 %: n=10median 98.37 Purity (% area) Reports
Figure 2. Purity distribution across all 492 Retatrutide records. Dashed line is this compound's median (98.37 %); the solid vertical is the index acceptance specification for the incretin analogues and co-agonists class (96.5 %). 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.

95.596.397.197.998.799.5100.3HomopeptideHomopeptide: Q1 98.23, median 98.68, Q3 98.99, n=64n=64GGPepsGGPeps: Q1 98.01, median 98.44, Q3 98.81, n=56n=56TFCTFC: Q1 98.31, median 98.53, Q3 98.75, n=43outlier 97.26outlier 97.57outlier 99.44n=43PPGPPG: Q1 98.23, median 98.56, Q3 99.01, n=35n=35QYBQYB: Q1 98.29, median 98.47, Q3 98.63, n=28outlier 97.75outlier 99.36outlier 99.52n=28QSCQSC: Q1 98.59, median 99.03, Q3 99.31, n=28n=28ASYASY: Q1 97.98, median 98.36, Q3 98.88, n=26n=26WWBWWB: Q1 99.03, median 99.20, Q3 99.49, n=22n=22HYBHYB: Q1 98.22, median 98.35, Q3 98.66, n=21outlier 99.58n=21SSASSA: Q1 97.28, median 97.68, Q3 97.90, n=20n=20SWBSWB: Q1 97.92, median 98.25, Q3 98.66, n=20n=20SinoPepSinoPep: Q1 97.52, median 97.70, Q3 97.96, n=17outlier 98.86n=17HJHJ: Q1 97.77, median 98.11, Q3 98.33, n=16n=16GSPGSP: Q1 97.69, median 97.83, Q3 98.00, n=16n=16KPKP: Q1 96.47, median 96.69, Q3 98.19, n=14n=14TFSTFS: Q1 98.27, median 98.68, Q3 98.83, n=14n=14AMBAMB: Q1 98.15, median 98.18, Q3 98.31, n=13outlier 97.75outlier 97.86outlier 98.67n=13JEEPJEEP: Q1 97.85, median 97.92, Q3 98.42, n=13n=13SIGSIG: Q1 97.33, median 97.97, Q3 98.19, n=9n=9CPCCPC: Q1 96.61, median 97.00, Q3 97.06, n=8n=8FGPFGP: Q1 98.29, median 98.76, Q3 98.80, n=5n=5BCHBCH: Q1 96.91, median 97.02, Q3 97.68, n=3n=3 Purity (% area)
Figure 3. Retatrutide 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
[D-Aib2]-diastereomer-0.22mass-identical95%0.211.67
des-Aib20 analogue-0.44-85.05386%0.191.52
oxidised Trp (+16 Da)-0.66+15.99574%0.082.28
C18 diacid regioisomer+0.58mass-identical74%0.122.16
truncated (5-39)-1.92-428.20169%0.172.67
aspartimide (−18 Da)+0.71-18.01164%0.081.59
incomplete Fmoc removal (+222 Da)+2.41+222.06858%0.082.15
retatrutide dimer+4.12+4728.48746%0.091.17

Degradation pathways

  • aspartimide formation and subsequent β-Asp isomerisation at Asp-Ser
  • Trp oxidation under fluorescent light in clear glass
  • aggregation above 2 mg/mL on freeze–thaw

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

Section 6

Clinical context

Included because it is routinely misapplied. Trial data describes a licensed medicinal product manufactured under a marketing authorisation, and it does not transfer to research-grade material of unknown provenance.

Retatrutide phase 2 data were published in NEJM (2023); the TRIUMPH phase 3 programme is ongoing. There is no approved retatrutide product anywhere, which makes independent analytical data on research material the only characterisation most buyers will ever see.

Section 7

Quarterly coverage

QuarterReportsMedian purityRange
2024-Q12698.6498.04–99.14
2024-Q22398.6297.82–99.93
2024-Q33098.2197.33–98.95
2024-Q45198.6397.26–99.78
2025-Q12198.2997.33–99.60
2025-Q25198.1796.81–99.93
2025-Q35498.1796.29–99.66
2025-Q44498.2296.76–99.02
2026-Q19598.8896.75–99.93
2026-Q25898.3096.52–99.31
2026-Q33998.3595.81–99.82

Quarter-by-quarter detail →

Section 8

Most recent records

The 25 most recent Retatrutide records of 492.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-042437HomopeptideHOMO-2605-V4718Nordanalyt2026-Q398.683.67102.8Buyer-sourced0PASS
AX-2026-043095KPKP-2607-H5774Janoshik2026-Q395.815.48105.2Buyer-sourced0FAIL
AX-2026-042282TFCTFC-2608-J1156Janoshik2026-Q398.544.27—Buyer-sourced0PASS
AX-2026-043094KPKP-2607-H5774PeptideMeter2026-Q396.326.40—Buyer-sourced0FAIL
AX-2026-042441HomopeptideHOMO-2605-V4718Medutest2026-Q398.934.22—Buyer-sourced0PASS
AX-2026-041427QYBQYB-2604-B4920PeptideMeter2026-Q397.932.45101.7Buyer-sourced0PASS
AX-2026-041786ASYASY-{CAT}-2288VendorInvestigate2026-Q398.786.59—Buyer-sourced0PASS
AX-2026-041428QYBQYB-2604-B4920Janoshik2026-Q398.353.20—Laboratory-retained0PASS
AX-2026-041793ASYASY-{CAT}-2288Nordanalyt2026-Q398.346.16104.8Buyer-sourced0PASS
AX-2026-041784ASYASY-{CAT}-2288PeptideMeter2026-Q398.156.2691.9Buyer-sourced0PASS
AX-2026-042440HomopeptideHOMO-2605-V4718Janoshik2026-Q398.374.17—Buyer-sourced0PASS
AX-2026-041429QYBQYB-2604-B4920Medutest2026-Q398.532.6999.8Buyer-sourced1MARGINAL
AX-2026-042283TFCTFC-2608-J1156Medutest2026-Q398.425.0994.5Buyer-sourced1FAIL
AX-2026-041431QYBQYB-2604-B4920Janoshik2026-Q398.632.3294.2Buyer-sourced0PASS
AX-2026-041432QYBQYB-2604-B4920Janoshik2026-Q398.462.1493.3Buyer-sourced0PASS
AX-2026-042439HomopeptideHOMO-2605-V4718Janoshik2026-Q398.683.61—Buyer-sourced0PASS
AX-2026-041788ASYASY-{CAT}-2288Janoshik2026-Q398.455.77—Buyer-sourced0PASS
AX-2026-041990AMBAMB-2606-N5977Janoshik2026-Q398.314.23—Buyer-sourced0PASS
AX-2026-041992AMBAMB-2606-N5977VendorInvestigate2026-Q398.173.7796.4Buyer-sourced0PASS
AX-2026-041991AMBAMB-2606-N5977Janoshik2026-Q398.204.00—Buyer-sourced0PASS
AX-2026-041435QYBQYB-2604-B4920Janoshik2026-Q398.342.53—Buyer-sourced0PASS
AX-2026-042284TFCTFC-2608-J1156Janoshik2026-Q398.274.45101.3Buyer-sourced0PASS
AX-2026-041785ASYASY-{CAT}-2288Janoshik2026-Q397.965.9290.6Laboratory-retained0PASS
AX-2026-041789ASYASY-{CAT}-2288Janoshik2026-Q398.376.1999.4Buyer-sourced0PASS
AX-2026-041434QYBQYB-2604-B4920Medutest2026-Q399.022.6596.9Laboratory-retained0PASS