AssayIndex
Non-peptide adjuncts

MK-677 (Ibutamoren mesylate)

ibutamoren · MK-0677 · nutrobal · C27H36N4O5S · CH4O3S · monoisotopic 624.2181 Da. The index holds 143 assay reports on this compound across 25 batches from 19 suppliers.

143 reports25 batchesmedian 99.49 %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.

MK-677 is a small molecule, not a peptide, and the index includes it because it is submitted constantly alongside peptides and because it is analytically instructive: peptide content, counter-ion by ion chromatography and Karl Fischer water are all replaced by assay-by-HPLC against a reference standard, residual solvents by GC headspace to ICH Q3C(R8), and sulfated ash. Roughly one in six MK-677 submissions reports a purity figure with no reference standard named, and the index records those as area-percent only, which for a small molecule with unknown relative response factors is a much weaker statement than it looks.

Compound class
Non-peptide adjuncts
Molecular formula
C27H36N4O5S · CH4O3S
Monoisotopic mass
624.2181Da
Average mass
624.77Da
Residues
—
Nominal retention (RG-2, 30 min)
13.86min
Retention window
0.30min
Counter-ion as usually shipped
mesylate
Typical label claims
250 mg · 500 mg · 1000 mg
Analytical difficulty (index scale)
0.80 — 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.

01939387958187758 MK-677 (Ibutamoren mesylate)13.86 min · 99.49 % 13.005.66 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 MK-677 (Ibutamoren mesylate) trace on the index reference method RG-2, constructed from this page's own numbers: the main peak carries the index median purity of 99.49 % area at the nominal retention time of 13.86 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 143 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 99.49% n=143
Interquartile range 0.69pp n=143
Minimum 97.90% n=143
Maximum 99.93% n=143
Pass rate vs spec 97.9% n=143
Median recovery vs claim 97.2% n=81
Median water 4.47% n=143
Median |mass error| 2.9ppm n=124
013263992.093.094.095.096.097.098.099.0100.092.00–92.25 %: 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=298.00–98.25 %: n=098.25–98.50 %: n=198.50–98.75 %: n=1098.75–99.00 %: n=1799.00–99.25 %: n=1899.25–99.50 %: n=2499.50–99.75 %: n=2599.75–100.00 %: n=46median 99.49 Purity (% area) Reports
Figure 2. Purity distribution across all 143 MK-677 (Ibutamoren mesylate) records. Dashed line is this compound's median (99.49 %); the solid vertical is the index acceptance specification for the non-peptide adjuncts 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.

97.798.198.598.999.399.7100.1HomopeptideHomopeptide: Q1 99.77, median 99.93, Q3 99.93, n=19outlier 99.27outlier 99.51n=19WXTWXT: Q1 99.10, median 99.29, Q3 99.59, n=17n=17QSCQSC: Q1 99.64, median 99.74, Q3 99.79, n=11n=11GSPGSP: Q1 99.41, median 99.47, Q3 99.62, n=10outlier 98.90outlier 99.93n=10FGPFGP: Q1 99.23, median 99.45, Q3 99.50, n=9n=9GGPepsGGPeps: Q1 99.79, median 99.81, Q3 99.93, n=9n=9HJHJ: Q1 99.46, median 99.73, Q3 99.93, n=9n=9SIGSIG: Q1 98.82, median 98.83, Q3 98.93, n=9outlier 98.38n=9GL BiochemGL Biochem: Q1 98.72, median 98.88, Q3 99.00, n=8n=8CPCCPC: Q1 98.61, median 98.75, Q3 98.81, n=7n=7MKMMKM: Q1 99.25, median 99.33, Q3 99.39, n=6outlier 98.98outlier 99.60n=6HYBHYB: Q1 99.83, median 99.87, Q3 99.93, n=5n=5BCHBCH: Q1 97.94, median 98.23, Q3 98.59, n=4n=4SWBSWB: Q1 99.40, median 99.56, Q3 99.74, n=4n=4TFCTFC: Q1 99.14, median 99.17, Q3 99.38, n=4outlier 99.87n=4PPGPPG: Q1 99.49, median 99.62, Q3 99.79, n=4n=4TFSTFS: Q1 99.10, median 99.14, Q3 99.31, n=3n=3KPKP: Q1 99.41, median 99.52, Q3 99.61, n=3n=3QYBQYB: Q1 99.81, median 99.85, Q3 99.89, n=2n=2 Purity (% area)
Figure 3. MK-677 (Ibutamoren mesylate) 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 base (des-mesylate, −96 Da)+0.04-96.01191%0.070.87
spiroindane regioisomer+0.44mass-identical85%0.071.02
sulfonamide hydrolysis product (+18 Da)-0.86+18.01176%0.161.14
O-desmethyl metabolite analogue (−14 Da)-0.52-14.01673%0.050.91
residual DMF (process solvent)-8.20-551.00069%0.060.57

Degradation pathways

  • sulfonamide hydrolysis under strongly basic conditions
  • no oxidative or proteolytic liability

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

Section 7

Quarterly coverage

QuarterReportsMedian purityRange
2024-Q10n<3—
2024-Q2699.8599.27–99.93
2024-Q31298.9098.38–99.71
2024-Q4999.1098.70–99.35
2025-Q11899.5498.90–99.93
2025-Q23699.2298.52–99.93
2025-Q32899.7899.44–99.93
2025-Q41899.8897.95–99.93
2026-Q1799.3197.90–99.60
2026-Q2999.2898.51–99.93
2026-Q30n<3—

Quarter-by-quarter detail →

Section 8

Most recent records

The 25 most recent MK-677 (Ibutamoren mesylate) records of 143.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-041633FGPFGP-2604-K8509PeptideMeter2026-Q299.814.9196.2Buyer-sourced0FAIL
AX-2026-041733TFSTFS-{CAT}-1096PeptideMeter2026-Q299.073.9395.1Laboratory-retained0FAIL
AX-2026-043468BCHBCH-2511-G5204Medutest2026-Q298.854.3096.5Buyer-sourced1FAIL
AX-2026-042647SWBSWB-2605-B7365Nordanalyt2026-Q299.282.8693.1Buyer-sourced0FAIL
AX-2026-041634FGPFGP-2604-K8509PeptideMeter2026-Q299.865.17—Buyer-sourced0FAIL
AX-2026-043469BCHBCH-2511-G5204Medutest2026-Q298.514.86—Buyer-sourced1FAIL
AX-2026-042648SWBSWB-2605-B7365Janoshik2026-Q299.932.6096.9Supplier-supplied0FAIL
AX-2026-041732TFSTFS-{CAT}-1096Janoshik2026-Q299.483.16106.4Buyer-sourced0FAIL
AX-2026-041734TFSTFS-{CAT}-1096PeptideMeter2026-Q299.143.6491.2Buyer-sourced0FAIL
AX-2026-043486BCHBCH-2601-G4997Kestrel2026-Q197.903.62100.3Laboratory-retained1FAIL
AX-2026-042974MKMMKM-2509-T3949Medutest2026-Q199.314.15—Buyer-sourced1FAIL
AX-2026-042973MKMMKM-2509-T3949Medutest2026-Q199.603.56—Supplier-supplied0FAIL
AX-2026-042975MKMMKM-2509-T3949PeptideMeter2026-Q199.233.69—Laboratory-retained0FAIL
AX-2026-042977MKMMKM-2509-T3949Janoshik2026-Q198.983.5393.6Buyer-sourced0FAIL
AX-2026-042976MKMMKM-2509-T3949PeptideMeter2026-Q199.403.48—Buyer-sourced0FAIL
AX-2026-043485BCHBCH-2510-P5124PeptideMeter2025-Q497.955.9989.0Buyer-sourced1FAIL
AX-2026-042972MKMMKM-2509-T3949Nordanalyt2026-Q199.342.69—Buyer-sourced0FAIL
AX-2025-019788HomopeptideHOMO-2506-L4686Janoshik2025-Q499.721.45—Buyer-sourced0FAIL
AX-2025-019791HomopeptideHOMO-2506-L4686VendorInvestigate2025-Q499.701.37102.4Buyer-sourced0FAIL
AX-2025-019789HomopeptideHOMO-2506-L4686Medutest2025-Q499.931.59—Buyer-sourced0FAIL
AX-2025-019562TFCTFC-2511-N1358Janoshik2025-Q499.123.5089.3Buyer-sourced1FAIL
AX-2025-019793HomopeptideHOMO-2506-L4686Janoshik2025-Q499.511.23—Buyer-sourced0FAIL
AX-2025-019792HomopeptideHOMO-2506-L4686Janoshik2025-Q499.891.4095.5Buyer-sourced0FAIL
AX-2025-019787HomopeptideHOMO-2506-L4686Janoshik2025-Q499.931.8191.7Buyer-sourced0FAIL
AX-2025-019561TFCTFC-2511-N1358PeptideMeter2025-Q499.213.09106.5Buyer-sourced0FAIL