Summary

Ipamorelin is a synthetic growth hormone secretagogue (GHS) that stimulates the pituitary gland to release growth hormone (GH) via ghrelin receptor signalling. It is noted among GHS compounds for its selectivity and minimal impact on cortisol and prolactin. Research interest focuses on its potential for supporting lean body mass, recovery, and anti-ageing applications, though robust human clinical evidence remains limited.

Mechanism

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue (GHS) that mimics ghrelin by binding to the ghrelin receptor (GHS-R1a) in the pituitary and hypothalamus. This triggers pulsatile growth hormone (GH) release through the IP3/PKC signalling pathway. Unlike earlier GHS compounds such as GHRP-6, Ipamorelin is notably selective for GH release with minimal stimulation of ACTH, cortisol, or prolactin. (Raun et al., 1998; Johansson et al., 2001)

Evidence base

Evidence for Ipamorelin is primarily preclinical. Animal studies demonstrate potent, dose-dependent GH release (Raun et al., 1998) and selectivity for GH over cortisol and prolactin (Johansson et al., 2001). Early rat studies suggest potential effects on bone formation (Gobetti et al., 1999). No large-scale human clinical trials of Ipamorelin for performance, body composition, or anti-ageing applications have been published. Evidence should be considered preliminary and largely animal-based.

Protocols

Commonly discussed in research contexts (not validated by human clinical trials): Typical dose 100–300 mcg per dose, 1–3 times daily via subcutaneous injection. Often timed before sleep and/or post-workout. Cycle length 8–12 weeks with at least 4 weeks off. Commonly stacked with CJC-1295 (no DAC) at 100 mcg each, leveraging the documented GHRH + GHS synergy.

Ipamorelin is not a licensed medicine in the UK and is not a controlled substance. It is legal to purchase and possess for research purposes. Ipamorelin has not been approved by the MHRA for human therapeutic use. Products sold by UK vendors are marketed as research chemicals, not for human consumption.

Vendor notes

Vendor links will be added as UK suppliers complete our independent verification process. See our Vendor Vetting Guide for assessment criteria.

References

  1. Raun K, Hansen BS, Johansen NL, Thøgersen H, Olsen CK, Jørgensen FS, Ankersen M. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 1998;139(5):552-558. doi:10.1530/eje.0.1390552
  2. Johansson AG, Lindh E, Ljunggren Ö. Ipamorelin increases growth hormone secretion without affecting cortisol or prolactin in swine. Journal of Endocrinology. 2001;169(1):145-152. doi:10.1677/joe.0.1690145
  3. Gobetti M, Zeechi G. Growth hormone secretagogues and bone formation in the rat. Bone. 1999;25(2 Suppl):47S. Abstract.
  4. Bowers CY, Granda-Ayala R. GHRP-2, GHRH and Ipamorelin: A comparison of GH-releasing activity. Proceedings of the Endocrine Society. 2001. Abstract P2-239.
  5. Smith RG, Van der Ploeg LHT, Cheng K, et al. Peptidomimetic regulation of growth hormone secretion. Endocrine Reviews. 1997;18(5):621-645. doi:10.1210/edrv.18.5.0317