AssayIndex
Acceptance specification

Growth-hormone axis peptides

GHRH analogues, growth-hormone secretagogues, IGF-1 variants and conjugates. 13 compounds in this class, 1,108 records.

13 compounds1,108 recordspurity spec 98.0 %observed median 99.00 %
Section 1

The specification

ParameterLimitWhere the limit came from
Purity by RP-HPLC≥ 98.0 % areaSet at the 14.7 th percentile of observed results for this class — low enough that ordinary material passes, high enough that a genuinely poor lot does not. Reviewed each quarter and last moved in 2025-Q1.
Water by Karl Fischer≤ 9.0 %Lyophilised peptides routinely carry 2–6 % residual water. The limit sits above the normal range and below the point at which water displaces enough cake mass to move the recovered-mass figure by more than the label tolerance.
Counter-ion≤ 12.0 %Derived from the stoichiometric maximum for a fully-protonated peptide of this class's typical basic-residue count, plus a margin. Above it, the salt is either non-stoichiometric or the cake contains free acid.
Bacterial endotoxin≤ 5.0 EU/mgAn index convention chosen so that the figure is comparable across records. It is not a pharmacopoeial limit: a real limit is dose-dependent and is computed per use from the K/M ratio. The endotoxin calculator does that calculation.
Mass accuracy± 15 ppmAchievable accuracy depends on mass. This class's limit reflects both the instrument capability and the mass differences that must be resolved within it — see mass-accuracy calibration.
Section 2

Compounds in this class

Per-compound thresholds override the class default where the chemistry requires it. Where a compound row differs from the class row above, the compound row wins.

CompoundMonoisotopic DaPurity specWaterCounter-ionppmRecordsObserved median
CJC-1295 (no DAC)3365.740298.09.012.01513798.61
CJC-1295 with DAC3644.974897.59.012.01513698.79
Ipamorelin711.385699.09.012.01522399.48
Sermorelin3355.724598.09.012.0159698.94
Tesamorelin5131.927697.09.012.0152198.43
GHRP-2817.427599.09.012.0159799.22
GHRP-6872.444699.09.012.01516999.65
Hexarelin886.460299.09.012.0154398.72
IGF-1 LR39105.241295.09.012.0158697.75
IGF-1 DES (1-3)7365.718895.09.012.0152898.53
MGF2886.511797.59.012.0153298.73
PEG-MGF7894.000092.09.012.0153597.92
Follistatin-344—98.09.012.0155n<3
Section 3

What actually fails, and how often

A specification nobody fails is not a specification. These are the failure rates the thresholds above produce on the records the index holds.

ParameterLimitRecords outsideRate
Purity≥ 98.0 % area20118.14%
Water≤ 9.0 %00.00%
Counter-ion≤ 12.0 %00.00%
Endotoxin≤ 5.0 EU/mg201.81%
Mass accuracy± 15 ppm484.33%
06112218392.093.094.095.096.097.098.099.0100.092.00–92.25 %: 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=495.75–96.00 %: n=496.00–96.25 %: n=696.25–96.50 %: n=196.50–96.75 %: n=996.75–97.00 %: n=1297.00–97.25 %: n=1597.25–97.50 %: n=2297.50–97.75 %: n=3597.75–98.00 %: n=5498.00–98.25 %: n=9098.25–98.50 %: n=10198.50–98.75 %: n=8798.75–99.00 %: n=11099.00–99.25 %: n=12199.25–99.50 %: n=10899.50–99.75 %: n=10999.75–100.00 %: n=215median 99.00 Purity (% area) Reports
Figure. Class-wide purity distribution with the acceptance specification drawn as a solid vertical and the observed median dashed. The area to the left of the solid line is the failure rate. A specification sitting deep in the left tail is doing its job; one sitting in the body of the distribution is measuring the population rather than screening it.