Pure North Peptides Journal · Compendium
Ipamorelin: selective ghrelin-receptor agonist research
Published 2025-09-14 · Pure North Peptides Editorial · Canada
Short answer. Ipamorelin is a 5-residue synthetic selective agonist of the ghrelin receptor (GHS-R1a) with no measurable activity at the cortisol-releasing or prolactin-releasing axes that some earlier GHS-class peptides engaged. Pure North ships HPLC-verified Ipamorelin 10 mg across Canada.
Sequence
Ipamorelin is a pentapeptide: H-Aib-His-D-2-Nal-D-Phe-Lys-NH₂, where Aib is α-aminoisobutyric acid and 2-Nal is 2-naphthylalanine. Mass 711.86 Da. The use of two non-natural residues (Aib and 2-Nal) plus D-amino-acids drives selectivity for GHS-R1a over GHS-R1b and the off-target receptors that GHRP-2 and GHRP-6 engage.
Why selectivity matters
Earlier ghrelin-receptor agonists in the GHRP series (GHRP-6, GHRP-2, hexarelin) showed cross-reactivity with the cortisol-releasing axis and the prolactin-releasing axis at typical research-effective concentrations. Ipamorelin's selectivity profile means in-vitro experiments isolating GHS-R1a effects don't carry the same confound load.
Reference-grade quality criteria
- RP-HPLC purity ≥ 99% at 220 nm.
- ESI-MS at theoretical mass 711.86 Da ± 0.3 Da.
- Stereochemistry verification: D-Phe and D-Nal residues confirmed by chiral HPLC.
- Net peptide content ≥ 85% by AAA.
Common in-vitro applications
Pituitary GH-release assays, GHS-R1a binding affinity (low-nanomolar in published assays), comparative pharmacology against the GHRP series, downstream calcium-flux signaling readouts. Ipamorelin is also used as a GHS-R-selective control alongside GHRP-2 and GHRP-6 to dissect off-target effects.
Reconstitution
Highly water-soluble. Reconstitute a 5 mg vial with 1.0 mL bacteriostatic water for 5 mg/mL stock. Dissolves immediately. Stable 28 days at 2–8 °C; longer storage as −80 °C aliquots.
Stack research with CJC-1295
Ipamorelin is commonly studied alongside CJC-1295 (the GHRH-analog side of the growth-axis pair) to demonstrate the GHRH+GHS synergy in receptor co-engagement work. Pure North stocks both as separate reference standards — CJC-1295 (No DAC) and Ipamorelin — so labs can run independent dose-response curves for each.
Pure North Peptides ships HPLC-verified Ipamorelin 10 mg across Canada — dispatched within 2 business days, with typical Canada Post Xpresspost transit around 4 days. View Ipamorelin on the catalog →
Frequently asked questions
How does Ipamorelin differ from GHRP-2?
Ipamorelin is selective for GHS-R1a; GHRP-2 has additional cortisol- and prolactin-axis activity at typical research concentrations. The selectivity makes Ipamorelin a cleaner tool for dissecting GHS-R1a-specific effects.
Why are non-natural residues used?
Aib (α-aminoisobutyric acid) and 2-Nal (2-naphthylalanine) plus D-amino-acid substitutions drive both selectivity and protease resistance. Native L-amino acids in the same positions would be less selective and more degradation-prone.
What is Ipamorelin's molecular weight?
711.86 Da. ESI-MS confirmation should be within 0.3 Da on a competent COA.
Storage protocol?
Lyophilized, sealed under nitrogen. After reconstitution, 2–8 °C for 28 days or −80 °C aliquots.
Where to source Ipamorelin in Canada?
Pure North Peptides stocks Ipamorelin 10 mg at /products/ipamorelin/; HPLC-verified, Janoshik-tested, dispatched within 2 business days with typical transit around 4 days.
Disclaimer: All Pure North Peptides products are supplied for laboratory research use only. They are not approved by Health Canada as drugs. See our research-use declaration for full terms.