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Peptide Spencer

Growth hormone secretagogue; selective ghrelin receptor (GHSR-1a) agonist (pentapeptide)

Ipamorelin

Also known as NNC 26-0161, Ipamorelin acetate

Limited human data

Not FDA-approved. Not on FDA's 503A category lists (May 14, 2026). Source, May 14, 2026

Identity. Ipamorelin is the synthetic pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2 (Novo Nordisk compound NNC 26-0161; formula C38H49N9O5, about 711.9 g/mol). It is a ghrelin-receptor (GHS-R1a) agonist and growth hormone secretagogue. The FDA compounding page names the substance 'Ipamorelin acetate'. It is not established whether the formulary 10 mg vial is the acetate salt or free base, or whether 10 mg is net peptide content or gross weight. Ask the dispensing pharmacy, because mcg doses depend on it. Do not confuse ipamorelin with the GHRH analogs (CJC-1295, sermorelin) that are often combined with it in practice. The formulary lists ipamorelin 10 mg alone and inside blends. Each blend component needs its own dosing (see practice.blend_caution).

At a glance

These dosages are a helpful guide, not a prescription. Every clinician is expected to do their own due diligence before prescribing.

  1. Start

    0.03 mg/kg per dose, intravenous infusion (postoperative ileus trial)1

    Human study
Frequency
twice daily1
Route
intravenous infusion1
Course
postoperative day 1 to 7 or hospital discharge1

Both human studies used intravenous dosing only; no subcutaneous human dosing is established, so do not extrapolate these figures to subcutaneous use.

Calculate this dose

Dosing detail

Human studies

Human study

  • Intravenous inpatient dosing in a surgical population only. Adults after small or large bowel resection with postoperative ileus; ipamorelin arm vs placebo. This is not a subcutaneous dose. Do not extrapolate it to practice dosing.

    0.03 mg/kg1

    Route
    intravenous infusion
    Frequency
    twice daily
    Duration
    postoperative day 1 to 7 or hospital discharge
    n
    117 enrolled; 114 in safety/modified intent-to-treat
    Design
    Multicenter, double-blind, placebo-controlled randomized phase 2 proof-of-concept (NCT00672074)
    Source quote
    The intervention was intravenous infusions of 0.03-mg/kg ipamorelin vs placebo twice daily, on postoperative day 1 to 7 or hospital discharge.

    Finding. Median time to first tolerated meal was 25.3 h vs 32.6 h (p=0.15). There were no significant differences in key or secondary efficacy endpoints, and the abstract reports the drug was well tolerated. FDA's compounding page separately cites serious adverse events including death with intravenous use. The trial abstract and registry record do not reconcile this.

  • Intravenous infusion in healthy men. This is not a subcutaneous dose. Do not extrapolate it to practice dosing. Dose-escalation pharmacokinetic and pharmacodynamic study of GH response.

    4.21, 14.02, 42.13, 84.27 and 140.45 nmol/kg2

    Route
    intravenous infusion over 15 minutes
    Frequency
    single infusion per dose level
    Duration
    single dose
    n
    8 healthy men per dose level (5 levels)
    Design
    Dose-escalation, 5 infusion rates, healthy volunteers
    Source quote
    A trial was conducted with a dose escalation design comprising 5 different infusion rates (4.21, 14.02, 42.13, 84.27 and 140.45 nmol/kg over 15 minutes) with eight healthy male subjects at each dose level.

    Finding. Dose-proportional PK; terminal half-life 2 hours; each dose produced a single GH release episode peaking at 0.67 hours.

Clinical practice

Clinical practice

The primary numbers come from one non-peer-reviewed educational page that labels them 'Anecdotal' or 'Mixed' and cites no dosing source. A peer-reviewed narrative review independently restates the dose range as forum behavior, not clinical recommendation. Two other peer-reviewed reviews state that dosing, frequency and duration are not established. Treat these figures as unverified community practice, not a recommendation. No subcutaneous human trial supports any figure.

Start
100 to 150 mcg (community 'conservative starter' tier)
Titration
No explicit titration schedule is given by the source. It lists three tiers (conservative starter, standard, advanced) without step rules.
Typical
200 to 300 mcg per dose; '200 mcg pre-sleep is the most-cited single dose in community reports'
Ceiling
300 mcg per dose, 2 to 3 times daily (community 'advanced' tier)
Frequency
Starter once daily; typical 1 to 2 times daily; advanced 2 to 3 times daily, spaced at least 6 hours apart
Route
Subcutaneous injection
Timing
Pre-sleep, to ride the natural GH pulse. The source's FAQ also advises avoiding carbohydrates for about 2 hours before injecting (a paraphrase; re-check the exact wording on the live page before quoting).
Cycle
The community source gives 8 to 12 weeks, often 5 days on / 2 days off, or continuous low-dose with periodic reassessment. A 2026 peer-reviewed narrative review summarizing forum protocols gives 8 to 12 weeks on followed by 4 to 6 weeks off. The two cycle patterns do not agree.

Sources

  • Clinical practicePeer-reviewed review4
    typical cycle: 8-12 weeks on, followed by 4-6 weeks off; 200-300 µg SC 2 or 3 injections/day (Table 2, bodybuilding-forum regimen); this practice is largely driven by anecdotal rationale
  • Clinical practicePeer-reviewed review5
    Importantly, information regarding the indications, dosing, frequency, and duration of treatment remains unknown.
  • Clinical practicePeer-reviewed review6
    Second, optimal dosing regimens remain poorly defined for most peptides. Current protocols are based on preclinical extrapolation, anecdotal clinical experience, or single-dose pharmacokinetic studies rather than on systematic dose-finding trials.

What clinics and vendors publish

These ranges come from clinic and vendor publications, not studies.

Community-reported
  • Community-reportedOther web source3
    Conservative starter: 100 to 150 mcg, Once daily, 8 to 12 weeks. Standard: 200 to 300 mcg, 1 to 2 times daily, 8 to 12 weeks, often 5 days on / 2 days off. Advanced: 300 mcg, 2 to 3 times daily, spaced at least 6 hours apart. Community range: 100 to 300 mcg per injection, 1 to 3 times daily. Route: Subcutaneous injection. No approved clinical dose (development discontinued).

Safety

Serious warnings

  • FDA compounding page: 'A study published in literature identified serious adverse events including death' when ipamorelin was given intravenously to improve gastric motility. FDA lacks sufficient information on harm via other injectable routes. This is FDA's characterization. The linked trial abstract reports the drug as well tolerated and does not mention death, and the registry record has no posted results, so the discrepancy cannot be resolved from the sources.7
  • FDA compounding page: compounded drugs containing ipamorelin acetate 'may pose risk for immunogenicity for certain routes of administration' because of potential aggregation or peptide-related impurities. The peptide also contains unnatural amino acids.7
  • No ipamorelin label was identified in the cited sources, so there is no boxed warning or label warning to quote (confirm on Drugs@FDA before relying on this).

Contraindications

  • None are formally defined, because no label was identified. Use caution or seek specialist input in these settings, pending more data: prior malignancy, strong family history of cancer, premalignant conditions, or other reasons for increased baseline cancer susceptibility (sustained IGF-1 elevation is a biologically plausible but unproven risk amplifier); and dysglycaemia or diabetes.4
  • Groups excluded from the only RCT (clinically unstable, significant liver disease, clinically significant lab or EKG abnormalities, alcohol or illicit drug abuse): no human safety data.8
  • Pregnancy and lactation: no data in any source reviewed. The only RCT required that females not be pregnant and does not address lactation, so no human safety data exist for either.8

Adverse effects

  • Phase 2 intravenous trial in postoperative ileus: the overall incidence of treatment-emergent adverse events was 87.5% with ipamorelin vs 94.8% with placebo. The abstract states 0.03 mg/kg IV twice daily for up to 7 days 'was well tolerated'. Read this alongside FDA's statement of serious adverse events including death with intravenous use. The trial abstract and registry record do not reconcile the two.1
  • Class analog data, not ipamorelin data: a review of GH secretagogues in hypogonadal men said adverse effects were 'rare and similar to those reported with sermorelin'. Sermorelin is a GHRH analog acting on a different receptor. Nausea, facial flushing and injection-site redness were listed for sermorelin.9
  • A 2026 narrative review of GH-IGF-1 axis peptides lists adverse effects reported across the class: endocrine and metabolic disturbances (including prolactin and cortisol elevations, appetite changes, dysglycaemia), fluid retention, myalgia and arthralgia, and injection-site reactions. These are class-level findings drawn largely from unregulated self-administration.4
  • Long-term safety data for ipamorelin are absent.6

Monitoring

  • Check fasting glucose or HbA1c at baseline and periodically. No ipamorelin-specific schedule is published. This is class-level guidance from a narrative review of GH-IGF-1 axis peptides, not from a trial.4
  • Check IGF-1 at baseline and on treatment for sustained elevation, with a low threshold for oncologic evaluation if symptoms arise. This is a class-level precaution drawn from the review's discussion of mitogenic risk. No ipamorelin schedule is published.4

Evidence

No FDA-approved ipamorelin product exists. Human data are intravenous only: a dose-escalation pharmacokinetic and pharmacodynamic study in healthy men (n=8 per level) and one phase 2 intravenous trial in postoperative ileus that found no significant efficacy difference versus placebo. No human trial of subcutaneous dosing was found. Subcutaneous practice dosing rests on anecdotal community protocols, not trials. The remaining evidence is from animals.

Mechanism

Ipamorelin is a synthetic pentapeptide that binds the ghrelin/GHS receptor (GHSR-1a) and stimulates pituitary GH release. In swine it released GH with potency similar to GHRP-6. Unlike GHRP-6 and GHRP-2, it did not raise ACTH or cortisol above levels seen with GHRH stimulation, even at doses over 200-fold above the GH ED50. That ACTH and cortisol finding comes from swine. For humans, a 2026 narrative review says only that no significant effects on other pituitary or adrenal hormones were reported in the phase I setting. The human data are thin.410

Availability

Amounts offered

  • 10 mg

Custom strengths on request.

Book a call

References

According to PubMed

  1. 1Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.Int J Colorectal Dis 29(12):1527-34, 2014
  2. 2Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.Pharm Res 16(9):1412-6, 1999
  3. 3Ipamorelin report (community dosing protocols labeled Anecdotal/Mixed; no cited dosing sources)outliyr.com, 2026
  4. 4The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.Front Endocrinol (Lausanne) 17:1822475, 2026
  5. 5Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.Am J Sports Med 54(1):223-229, 2026
  6. 6Therapeutic peptides in gerontology: mechanisms and applications for healthy aging.Front Aging 7:1790247, 2026
  7. 7Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Content current as of 04/22/2026)U.S. FDA, Human Drug Compounding, 2026
  8. 8ClinicalTrials.gov NCT00672074 (ipamorelin in postoperative ileus; no results posted)ClinicalTrials.gov
  9. 9Beyond the androgen receptor: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males.Transl Androl Urol 9(Suppl 2):S149-S159, 2020
  10. 10Ipamorelin, the first selective growth hormone secretagogue.Eur J Endocrinol 139(5):552-61, 1998
  11. 11PCAC votes against four nominated bulk drug substances (L-theanine, ibutamoren mesylate, ipamorelin, kisspeptin-10)Alliance for Pharmacy Compounding (trade group report, secondary source; year not shown on page)
  12. 12Injectable Peptides in Sports Medicine: A Structured Narrative Review of Evidence, Safety, and Antidoping Implications.JBJS Rev 14(5), 2026

Last reviewed 2026-10-14. 34 figures checked against their sources. How this works