Ipamorelin (sometimes listed as NNC 26‑0161) is a selective growth hormone secretagogue (GHS) that binds the ghrelin receptor (GHSR‑1a) to trigger pulsatile GH release with minimal impact on ACTH or cortisol in preclinical models. Below you’ll find a concise answer, a properties table, outcomes‑focused mechanisms, step‑by‑step research‑handling guidance, comparisons vs. similar agents, a checklist, and FAQs. (PubMed)

Fast Answer / Executive Summary (40–60 words)

Ipamorelin is a pentapeptide ghrelin‑receptor agonist that selectively stimulates pulsatile growth hormone (GH) release without measurably raising ACTH/cortisol in animal models, and produces a short‑acting GH pulse in humans (peak ≈ 40 minutes; peptide t½ ≈ 2 hours). Mechanistically, it amplifies GH output via GHSR‑1a, complementing the GHRH pathway. Educational use only. (PubMed)

Ipamorelin — Entity Properties (educational)

Property Detail
Aliases / Synonyms Ipamorelin; NNC 26‑0161; UNII: Y9M3S784Z6
Family / Pathway Ghrelin receptor (GHSR‑1a) agonist; growth hormone secretagogue (GHS)
Sequence (AA) Aib–His–D‑2‑Nal–D‑Phe–Lys–NH₂ (pentapeptide)
Molecular Weight (Da) ~711.9
CAS 170851‑70‑4
Typical Diluent(s) (educational) Bacteriostatic Water for Injection, USP (sterile water with 0.9–1.1% benzyl alcohol; multi‑dose). Use per lab SOPs.
Example Concentration(s) (educational) Reconstitute 5 mg vial with 2.0 mL → 2.5 mg/mL; 10 mg with 4.0 mL → 2.5 mg/mL (math example; not medical dosing).
Storage (lyophilized / after reconstitution) Lyophilized peptides often stored at ≤ −20 °C protected from light; solutions are less stable—short‑term 2–8 °C; for longer storage, freeze aliquots per SOPs to avoid freeze–thaw cycles.

Sources: chemical identity from PubChem/DrugBank; diluent identity from DailyMed (USP); general peptide stability practices from peer‑reviewed reviews on peptide stability. (PubChem)

Core Concepts & Key Entities

What is Ipamorelin, precisely? Ipamorelin is a selective GHS that activates GHSR‑1a (the ghrelin receptor) to induce GH release while sparing other pituitary axes (ACTH/cortisol) in animal models. Early pharmacology work benchmarked this selectivity against GHRP‑6 and GHRP‑2; only ipamorelin avoided ACTH/cortisol elevations even at very high doses in swine. (PubMed)

How does Ipamorelin generate a GH “pulse”? In healthy volunteers, short infusions produced a single GH episode peaking around 0.67 hours (~40 minutes) with a peptide terminal half‑life near 2 hours—consistent with a brief, physiologic‑like pulse that returns to baseline. This profile lends itself to outcome‑focused protocols that respect GH’s natural pulsatility. (PubMed)

Where does GHSR‑1a fit in GH physiology? GHSR‑1a is a GPCR expressed in pituitary somatotrophs and hypothalamic circuits. Endogenous ghrelin boosts GH by synergizing with GHRH and by counteracting somatostatin’s inhibitory tone—explaining why GHSs can augment rather than replace physiologic pulsatility. Ipamorelin leverages this same receptor system. (PMC)

Why “timing” matters for outcomes. In adults, 60–70% of daily GH secretion clusters after sleep onset with slow‑wave sleep, so researchers sometimes align short‑acting GHS administration with times that do not blunt natural nocturnal pulses (educational perspective). The goal in research designs is to support rather than flatten physiologic rhythms. (JAMA Network)

Selectivity vs. older GHRPs. Classic GHRPs (e.g., GHRP‑6, hexarelin) can raise ACTH, cortisol, and prolactin, especially with intravenous or high exposure, while ipamorelin showed minimal ACTH/cortisol effects in animal tests at doses >200× its GH ED50—an important distinction for interpreting endocrine “side‑signal” noise in experiments. (OUP Academic)

Information‑gain insight: Think of ipamorelin as a “precision tap” on the GH axis. Where GHRP‑6 acts like a broad faucet (GH + neuroendocrine spillover), ipamorelin behaves like a targeted lever: brief, focused GH pulses with less off‑target pituitary noise—a mechanistic nuance that often gets lost in simplified “all GHSs are the same” blog summaries. (PubMed)

Step‑by‑Step / How‑To (Educational; research handling)

Note: For research use only. Follow your institution’s SOPs, the product’s COA, and applicable regulations. The steps below are educational and not medical advice.

1) Verify identity & integrity

Confirm peptide name, lot, mass, and purity on the COA; inspect the lyophilized cake and vial seals. Cross‑check identifiers (CAS 170851‑70‑4, UNII Y9M3S784Z6). (PubChem)

2) Plan concentration math

Decide on an educational working concentration before opening the vial. Example: 5 mg + 2.0 mL → 2.5 mg/mL (or 10 mg + 4.0 mL → 2.5 mg/mL). Keep the math separate from any hypothetical dosing discussions.

3) Choose an appropriate diluent (per SOP)

For many injectable research formats, labs use Bacteriostatic Water for Injection, USP (sterile water plus 0.9–1.1% benzyl alcohol preservative) as a multi‑dose diluent. Validate compatibility with your application and SOP; do not use bacteriostatic diluents in neonates. (DailyMed)

4) Reconstitute with sterility and patience

Warm vial/diluent to room temperature; swab stoppers; inject diluent gently along the glass wall; swirl (avoid foaming). Do not shake vigorously—peptide solutions can aggregate under stress. (PMC)

5) Label clearly

Record compound, lot, concentration, diluent, date/time of reconstitution, and storage conditions. Maintain chain‑of‑custody and usage logs per QA.

6) Store to preserve integrity

General, educational guidance from peer‑reviewed peptide‑stability literature: lyophilized peptides are typically stable at ≤ −20 °C protected from light; solutions degrade faster—use 2–8 °C short‑term, and freeze aliquots (≤ −20/−80 °C) to limit freeze–thaw cycles when longer storage is required. Your SOP governs specifics. (PMC)

7) Dispose responsibly

Follow hazardous waste and bio‑safety procedures. Document disposal in your lab’s records.

Comparison / Alternatives (Ipamorelin vs. Common GHS/GHRH/GHS‑mimetics)

Bottom line: Ipamorelin is the most selective GH‑centric secretagogue among first‑generation GHRPs tested preclinically, producing brief, targeted GH pulses in humans. Longer‑acting options (e.g., CJC‑1295) change the timing of GH/IGF‑1 exposure, while oral MK‑677 (ibutamoren) increases 24‑h GH/IGF‑1 with appetite and mild metabolic effects reported. (PubMed)

Feature Ipamorelin GHRP‑6 / GHRP‑2 CJC‑1295 (DAC) MK‑677 (Ibutamoren)
Class / Target GHS; GHSR‑1a agonist GHS; GHSR‑1a agonists GHRH analogue (long‑acting) Oral GHS mimetic
GH Profile Short, pulse‑like GH burst; peak ≈ 0.67 h Pulsatile; often broader endocrine signal Sustained GH/IGF‑1 elevation days–weeks Elevated 24‑h GH/IGF‑1 over months
Selectivity (ACTH/cortisol) Minimal ACTH/cortisol in animal tests, even at high doses Often increases ACTH/cortisol & prolactin (esp. IV/high dose) GH‑centric (via GHRH receptor) Cortisol ↑ modestly; appetite ↑
Approx. Half‑life ~2 h (peptide t½) Short ~6–9 days (effective t½) Oral daily; long PD
Notable Considerations Targeted GH pulse; selective profile Appetite stimulation common; broader pituitary effects Long persistence—align with study aims ↑ FFM but also ↑ weight; glucose/insulin sensitivity shifts in older adults
Key Evidence Selectivity (animal); PK/PD in humans Endocrine spillover (ACTH/PRL) Human PK/PD and IGF‑1 dynamics 12‑month RCT in older adults

Sources: Ipamorelin selectivity and human PK/PD; GHRP endocrine effects; CJC‑1295 half‑life; MK‑677 effects. (PubMed)

Templates / Checklist / Example

Copy‑ready Research Checklist (educational)

  • Confirm compound identity (ipamorelin; CAS 170851‑70‑4; UNII Y9M3S784Z6) and inspect packaging. (PubChem)
  • Align study aims with GH pulsatility (short pulse vs. sustained exposure). (JAMA Network)
  • Select a diluent that matches SOPs (e.g., Bacteriostatic Water for Injection, USP, multi‑dose). (DailyMed)
  • Plan a target concentration (e.g., 5 mg in 2.0 mL → 2.5 mg/mL) and document calculations.
  • Reconstitute gently; avoid foaming/shaking; mix patiently to limit aggregation. (PMC)
  • Label vial with compound, lot, concentration, diluent, date/time, storage.
  • Store lyophilized at ≤ −20 °C (protected from light); use 2–8 °C short‑term for solutions; freeze aliquots to minimize freeze–thaw. (PMC)
  • Monitor any co‑measured endocrine endpoints (e.g., ACTH/cortisol) when comparing different GHSs. (OUP Academic)
  • Record usage, stability observations, and disposal per QA requirements.

FAQs (clear, answer‑first; educational)

1) What is Ipamorelin?
Ipamorelin is a selective growth hormone secretagogue that activates the ghrelin receptor (GHSR‑1a) to produce a brief, physiologic‑like GH pulse. It is a pentapeptide (Aib‑His‑D‑2‑Nal‑D‑Phe‑Lys‑NH₂) developed to maximize GH selectivity relative to older GHRPs. Educational use only. (PMC)

2) How long does Ipamorelin last?
Ipamorelin’s GH effect in humans peaks at ~0.67 hours (~40 minutes) with a peptide half‑life of ~2 hours, based on infusion PK/PD modeling. The GH rise is episodic and declines back to baseline thereafter. (PubMed)

3) Does Ipamorelin affect cortisol or prolactin like GHRP‑6?
Ipamorelin did not increase ACTH/cortisol above GHRH‑like levels in animal studies even at >200× its GH ED50, whereas GHRP‑6 and related agents can raise ACTH/cortisol and prolactin depending on exposure and route. (PubMed)

4) Can Ipamorelin be combined with a GHRH analogue (e.g., CJC‑1295) in research?
Ghrelin‑pathway agonism (GHSR‑1a) and GHRH signaling are mechanistically complementary, and literature describes synergy between ghrelin and GHRH on GH release; CJC‑1295 provides long‑lasting GHRH‑receptor stimulation. Research designs must weigh pulse timing vs. sustained exposure. (PMC)

5) What outcomes are associated with GHS exposure in human trials?
Outcomes depend on the agent and exposure pattern. For example, oral MK‑677 increased fat‑free mass and IGF‑1 in older adults but also increased appetite, body weight, fasting glucose, and cortisol modestly—useful context when comparing short‑pulse (ipamorelin) vs. chronic (oral) exposure designs. (PMC)

6) Is Ipamorelin permitted in sport?
No. Growth‑hormone‑releasing factors and secretagogues—including ipamorelin—are on the WADA Prohibited List at all times. Researchers working with athlete populations must refer to current antidoping rules. (Wada-Ama)

7) What risks should researchers monitor when studying GH modulation?
GH pathway modulation can relate to fluid retention, paresthesias, arthralgia, insulin sensitivity shifts, and lipid changes, particularly when exposure is sustained. These effects are documented in GH‑therapy literature and are relevant context when designing or interpreting GHS studies. (PMC)

Next Steps

If your goal is an educational, outcomes‑oriented overview with practical lab math and reconstitution details, bookmark PeptideDosages.com’s ipamorelin protocol pages:

When you’re ready to source research‑grade material from a supplier that emphasizes testing and quality controls, see:

Key takeaway: Ipamorelin is best understood as a short‑acting, GH‑selective “pulse tool” via GHSR‑1a—useful for research questions where timing and endocrine selectivity matter. Educational content only; no medical advice. (PubMed)