Ipamorelin

From Retapedia, the free peptide encyclopedia
Medical disclaimer. This article is for informational purposes only and does not constitute medical advice. Consult a qualified clinician before considering any compound discussed below. See Retapedia : Medical disclaimer.

Summary

What it does
Ipamorelin is used for sleep quality, recovery, and body composition. A Phase 2 trial in slow bowel recovery after surgery failed to beat a dummy treatment.
How it works
A five-part peptide injected under the skin. It triggers the same receptor as the hunger hormone ghrelin, so the pituitary gland releases growth hormone without a rise in the stress hormone cortisol or the milk-making hormone prolactin.
WADA status
Prohibited by the World Anti-Doping Agency (WADA). Drug-tested athletes cannot use it.

Ipamorelin (also known as NNC 26-0161) is a modified peptide studied for its effects on growth hormone, sleep, and aging. Selective GHS-R1a agonist pentapeptide raising GH without cortisol or prolactin effects. Phase 2 trial failed; not FDA-approved; limited human data.

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) selective agonist of the ghrelin/growth hormone secretagogue receptor (GHS-R1a) derived from GHRP-1. Highly selective for GH release without affecting cortisol, prolactin, ACTH, or acetylcholine at any dose (even 200-fold above ED50), distinguishing it from GHRP-2/GHRP-6. Binds to GHSR on pituitary somatotroph cells, activating phospholipase C (PLC) to generate IP3 and DAG, mobilizing intracellular calcium and activating protein kinase C for GH vesicle exocytosis.

Natty status
Ipamorelin is classified as not natty. It is prohibited by WADA and most natural bodybuilding federations. Use places the athlete in the enhanced category. See § Natty status.
Contents [hide]
  1. 1 Overview
  2. 2 Mechanism of action
  3. 3 Reported effects
  4. 4 Dosage and administration
  5. 5 Natty status
  6. 6 Research
  7. 7 Related compounds
  8. 8 Frequently asked questions
  9. 9 References
  10. 10 External links

Overview

Preclinical studies showed dose-dependent increases in GH levels, longitudinal bone growth, and body weight gain in rats, though IGF-1 levels and bone markers remained unchanged.

Phase 2 clinical trials for post-operative ileus failed to show efficacy (no reduction in time to first meal vs placebo).

Limited clinical data on body composition effects in humans despite theoretical benefits.

Typical dosing: 100-300mcg subcutaneously 1-3x daily, preferably on empty stomach.

Best timing: pre-bed (aligns with natural GH surge, improves sleep quality), split dosing (AM fasted + pre-bed) for enhanced pulsatility.

Users report improved sleep quality within 2-4 weeks, with body composition changes over 3-6 months.

Cycling protocol: 8-12 weeks on, with 5-days-on/2-days-off weekly pattern to prevent receptor desensitization.

Minimal side effects: injection site reactions, mild headache, nausea (typically resolve in 1-2 weeks).

Does not suppress endogenous hormone production.

Not FDA-approved; removed from FDA Category 2 compounding list September 2024 due to nominator withdrawal.

FDA recommended against inclusion in 503A Bulks Regulation October 2024 due to insufficient safety data.

No longer available for compounding.

As a growth hormone secretagogue, it is prohibited by WADA under category S2 (peptide hormones, growth factors, and related substances), banned both in and out of competition.

Mechanism of action

Selectively triggers growth hormone release without raising cortisol or prolactin. Human efficacy unproven: a Phase 2 trial failed and body-composition benefits remain preclinical. Subcutaneous injection.

Reported effects

Effects reported in the literature and from preclinical models include:

  • Released growth hormone from primary rat pituitary cells, in anaesthetised rats, and in conscious swine through a GHRP-like receptor, with potency and efficacy similar to GHRP-6. [1] Preclinical
  • Did not raise ACTH or cortisol in swine beyond levels seen after GHRH stimulation, even at doses more than 200-fold above the effective dose for growth hormone release, and did not affect FSH, LH, prolactin, or TSH. [1] Preclinical
  • Dose-dependently increased longitudinal bone growth rate and body weight gain in adult female rats over 15 days of subcutaneous dosing, without changing total IGF-I or serum markers of bone formation and resorption. [2] Preclinical
  • Reduced cisplatin-induced body weight loss by approximately 24 percent during the late delayed phase in ferrets, but did not reduce acute or delayed emesis. [3] Preclinical
  • Inhibited electrically stimulated contractions of isolated ferret ileum by 54.4 percent, with an IC50 of 11.7 micromolar. [3] Preclinical
  • Increased food intake, spermatocyte and early spermatid numbers, and serum luteinizing hormone and 11-ketotestosterone in tilapia after 21 days of dosing. [4] Preclinical

Evidence grades: FDA approvedApproved (non-US)Phase IIIPhase IIPhase IPreclinicalAnecdotal

Dosage and administration

⚠
Dosage information is included for encyclopedic purposes only. Retapedia does not provide medical advice. See Retapedia : Medical disclaimer.

Standard dose

  • 100-300mcg per injection, 1-3x daily (subcutaneous)

General

  • Beginners/anti-aging: 200mcg once daily at bedtime
  • Fat loss/general support: 200-300mcg twice daily (AM + pre-bed)
  • Performance/recovery: 300mcg three times daily (AM + post-workout + pre-bed)

Timing

  • On empty stomach, 30-60 min before/after meals

Best time

  • 2 hours before bedtime for sleep and natural GH alignment

Split dosing

  • Space 6-8 hours apart to mimic natural GH pulses

Cycle

  • 8-12 weeks on, with 5-days-on/2-days-off weekly pattern

Results timeline

  • Sleep improvements 2-4 weeks, body composition 3-6 months

Natty status

See also: Peptide § Natty status

Ipamorelin is classified as not natty. It appears on the WADA prohibited list and is banned by major natural bodybuilding federations.[5] Use of this compound places the athlete in the enhanced category rather than the natural category in competitive contexts.

Research

1 active clinical trial on record . 3 registered in total , of which 2 completed — highest phase ever: Phase 2
View on ClinicalTrials.gov · fetched Oct 5, 2026

The peptide has been the subject of 9 studies and reference works collected on this site. Additional bibliography is in § External links below.

Other peptides in this catalogue with overlapping mechanisms or status:

Epithalon Not natty
Marketed as an anti-aging peptide. In preclinical studies it boosts telomerase activity, supports the body's own melatonin production, and shows antioxidant effects. Human evidence is minimal.
MK-677 Not natty
Oral ghrelin receptor agonist that raises growth hormone and IGF-1. Increases lean mass, bone density, and deep sleep. Causes insulin resistance and elevated blood sugar.
Delta-sleep-inducing peptide Not natty
A neuropeptide named for inducing delta EEG sleep activity in animals, though its own link to human sleep is weak and poorly characterized. Shows preclinical antiepileptic activity.
CJC-1295 Not natty
Raises growth hormone 2-10 fold and IGF-1 for over a week per injection. Weekly subcutaneous dosing. Investigational only; cardiovascular risks and product-quality concerns.

Frequently asked questions

What is Ipamorelin?

Selective GHS-R1a agonist pentapeptide raising GH without cortisol or prolactin effects. Phase 2 trial failed; not FDA-approved; limited human data.

What is Ipamorelin used for?

Ipamorelin is used for sleep quality, recovery, and body composition. A Phase 2 trial in slow bowel recovery after surgery failed to beat a dummy treatment.

How does Ipamorelin work?

A five-part peptide injected under the skin. It triggers the same receptor as the hunger hormone ghrelin, so the pituitary gland releases growth hormone without a rise in the stress hormone cortisol or the milk-making hormone prolactin.

Is Ipamorelin natty?

No. Ipamorelin is classified as not natty. It is prohibited by WADA and banned by most natural bodybuilding federations. Use places an athlete in the enhanced category.

Is Ipamorelin banned by WADA?

Yes. Ipamorelin is prohibited by the World Anti-Doping Agency (WADA), so drug-tested athletes cannot use it. Check the current WADA Prohibited List before competing.

How is Ipamorelin administered?

Ipamorelin is typically administered via: subcutaneous injection. Dosage and administration protocols vary; see the Dosage section for details.

References

  1. a b First selective GHS characterization study
  2. ^ Bone growth in rats research
  3. a b Cisplatin-induced weight loss study
  4. ^ Hypothalamic-pituitary-testicular axis effects
  5. a b World Anti-Doping Agency. (2026). Prohibited List 2026.

External links

Categories: Peptides | Performance-enhancing substances | Growth hormone | Sleep | GHS | Selective agonist

This page was last updated on October 5, 2026, at 07:24 (UTC).

Research last reviewed on October 5, 2026.

Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply.