Ipamorelin: what it is, how it works, research, benefits and safety profile

Peptology · 2026-06-04

Ipamorelin (Ipamorelin) is a selective GH secretagogue (GHRP), which binds to ghrelin receptors (GHS-R) and stimulates endogenous, pulsatile release of growth hormone (GH), with minimal impact on other hormones. Research data indicate that, unlike older GHRPs (GHRP-6/-2), Ipamorelin does not significantly increase ACTH/cortisol and does not alter prolactin/gonadotropins, which explains its improved tolerability. This article is based on published studies and data, as well as the summary on the product page at Peptology.

What is Ipamorelin?

Ipamorelin is a synthetic peptide and a selective GHS-R agonist, designed to activate the physiological GH–IGF-1 axis via natural GH pulses rather than by exogenous GH. Product descriptions and publications emphasize its cleaner hormonal profile and better tolerability compared with other GHRP peptides.

Mechanism of action (GH–IGF-1 axis)

1. Binding to GHS-R (ghrelin receptors) in the pituitary.
   
   
2. Pulsatile GH release (physiological dynamics).
   
   

Increase in IGF-1 → stimulated lipolysis, tissue remodelling, recovery.
The selectivity for GH and the lack of significant effects on ACTH/cortisol and prolactin have been reported in experimental and clinical observations, including comparisons with GHRP-6/-2.

What the studies show (summary)

• GH selectivity – significant increase in GH without changes in PRL/LH/FSH/TSH; no increases in ACTH/cortisol, similar to responses after GHRH.
  
  
• Efficacy and tolerance – publications and reviews report increases in GH/IGF-1 and rare adverse events, comparable in frequency/character to GHRH analogues.
  
  
• Combination use – frequently studied together with GHRH analogues (e.g. CJC-1295) for synergy (GHRH + GHRP).
  
  

Note: Below we discuss scientific data and summaries. Products at Peptology are clearly labelled for research use only.

Benefits (research and practical context)

• Natural GH stimulation with selectivity and a milder hormonal profile.
  
  
• Support for recovery/sleep/regeneration (context of GH–IGF-1).
  
  
• Metabolic effect: indirect support for lipolysis/body composition (via IGF-1 and GH pulses).
  
  
• Combinations: potential synergy with CJC-1295 (without DAC) or other GHRH analogues.
  
  

Safety profile (data summary)

• Most common AEs: mild local reactions, transient headache, mild peripheral oedema/discomfort.
  
  
• Hormonal "cleanliness": it has been reported not to noticeably increase ACTH/cortisol and not to change PRL/LH/FSH/TSH – a key advantage over GHRP-6/-2. See more on PubMed. 
• Anti-doping: GH secretagogues (including Ipamorelin) are on the WADA Prohibited List (prohibited in sport). Check the current list.

Comparison: Ipamorelin vs GHRP-6/-2

• Selectivity: Ipamorelin ↑GH without ↑ACTH/cortisol; GHRP-6/-2 can elevate cortisol/ACTH.
  
  
• Tolerability: milder profile → preferred in models where GH selection and minimal hormonal side effects are desired.

Ipamorelin at Peptology (research use)

The product page presents an overview of the mechanism, key benefits, frequently asked questions and logistics. From there you can navigate to CJC-1295 (without DAC) and Sermorelin for research into the GH axis in combined protocols.

Frequently Asked Questions (FAQ)

• Is Ipamorelin a "GH injection"?
  No. It stimulates endogenous GH via GHS-R, and does not deliver GH exogenously.
  
  
• Does it raise cortisol/prolactin?
  Data show a lack of significant increases in ACTH/cortisol and no changes in PRL/LH/FSH/TSH.
  
  
• Does it make sense to combine with a GHRH analogue?
  Yes — synergy (GHRH + GHRP) is often sought for more physiological GH pulses.

Disclaimer

This material is for educational purposes only and is not medical advice. Research products are not intended for human use.

1. Peptology – Ipamorelin 2 mg (product page) – mechanism, benefits, positioning.
   
   
2. Raun et al., 1998 (PubMed): "Ipamorelin, the first selective growth hormone secretagogue" – selectivity, no ↑ACTH/cortisol.
   
   
3. Ishida et al., 2020 (Wiley review): GHS history/mechanism – selective ↑GH without change in PRL/FSH.
   
   
4. Sinha et al., 2020 (PMC review) – effects on body composition/GI, rare AEs.
   
   
5. WADA Prohibited List 2025/2026 – GHS (incl. Ipamorelin) are prohibited in sport.
   
   
6. Peptology – CJC-1295 without DAC; Sermorelin; Tesamorelin – context and internal links.