Tesamorelin / Ipamorelin

This profile summarizes a research-only co-administration concept pairing tesamorelin (a stabilized 44–amino-acid GHRH analogue) with ipamorelin (a selective ghrelin/GHSR-1a agonist). Tesamorelin activates the pituitary GHRH receptor (GHRHR) to increase pulsatile growth hormone (GH) release and raise IGF-1. Ipamorelin mimics endogenous ghrelin signaling at GHSR-1a to stimulate somatotrophs with minimal ACTH/cortisol activation compared with earlier GHRPs. Physiologically, GHRH and ghrelin pathways are complementary; in experimental settings, combining a GHRH analogue with a GHSR agonist can augment GH pulse amplitude and secretory responsiveness. This document provides neutral background for laboratory discussion and does not imply clinical use.

 

Chemical Structure / Identifiers — Tesamorelin

Property	Detail
Class/Target	GHRH analogue; agonist at GHRH receptor (GHRHR)
Length / Modification	44 amino acids; N-terminal trans‑3‑hexenoyl on Tyr¹ for DPP‑IV resistance
Molecular Formula (free base)	C221H366N72O67S
Approx. Molecular Weight	≈ 5131 g/mol (varies with salt/hydration)
CAS Number	218949‑48‑5 (tesamorelin); 901758‑09‑6 (tesamorelin acetate)
PubChem CID	16137828
Synonyms	TH9507; INN tesamorelin; tesamorelin acetate (salt)

Chemical Structure / Identifiers — Ipamorelin

Property	Detail
Sequence (pentapeptide)	Aib‑His‑D‑2‑Nal‑D‑Phe‑Lys‑NH₂ (Aib = aminoisobutyric acid; D‑2‑Nal = D‑2‑naphthylalanine)
Molecular Formula (free base)	C38H49N9O5
Molecular Weight (free base)	≈ 711.85 g/mol
CAS Number	170851‑70‑4
PubChem CID	9831659
Primary Target	GHSR‑1a (ghrelin receptor)
Synonyms	Ipamorelin; ipamorelin acetate (salt)

 

Primary Research Focus (Combined Rationale)

• Endocrine synergy (physiology): GHRH (tesamorelin) and ghrelin/GHSR agonism (ipamorelin) act via distinct, complementary receptors to enhance GH pulse amplitude and frequency; combination regimens in experimental settings may yield larger acute GH peaks than either agent alone.
• Body composition & metabolism: tesamorelin reduces visceral adipose tissue in HIV‑associated lipodystrophy; ipamorelin selectively elevates GH with minimal ACTH/cortisol activation compared with older GHRPs. Research interest centers on recovery, lean mass support, and metabolic endpoints.
• Mechanistic selectivity: ipamorelin shows limited off‑target endocrine effects at GH‑active doses in preclinical studies; tesamorelin engages the physiologic GHRH axis and secondarily raises IGF‑1.

 

Safety / Limitations

• Investigational pairing: no established clinical indication for combined tesamorelin + ipamorelin; evidence for additive benefits is mostly physiological and preclinical.
• Tesamorelin class warnings: may worsen glucose intolerance; monitor fasting glucose/HbA1c; avoid in active malignancy; monitor IGF‑1 elevations; common reactions include injection‑site events, arthralgia, myalgia, edema, and nausea.
• Ipamorelin: adverse events reported include nausea, flushing, headache, injection‑site reactions; generally minimal ACTH/cortisol effects versus older GHRPs, but endocrine responses are dose‑ and context‑dependent.
• Research Use Only: not approved for diagnosis, treatment, or prevention of disease; quality and identity must be verified for any laboratory work.

 

Key Publications / References

FDA Prescribing Information: Tesamorelin (EGRIFTA SV). https://www.egriftasv.com/documents/Prescribing-Information.pdf

PubChem Compound Summary: Tesamorelin (CID 16137828). https://pubchem.ncbi.nlm.nih.gov/compound/16137828

Ferdinandi ES et al. Nonclinical pharmacology and safety of TH9507 (tesamorelin), a stabilized GHRH analogue. Regul Toxicol Pharmacol. 2007. PubMed: https://pubmed.ncbi.nlm.nih.gov/17214611/

Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998. PubMed: https://pubmed.ncbi.nlm.nih.gov/9849822/

PubChem Compound Summary: Ipamorelin (CID 9831659). https://pubchem.ncbi.nlm.nih.gov/compound/Ipamorelin

Bowers CY. Growth hormone-releasing peptide (GHRP) and growth hormone secretagogue receptor (GHS-R). Endocrine. 2001 (synergy with GHRH discussed). PubMed: https://pubmed.ncbi.nlm.nih.gov/11767995/

Ghigo E et al. Endocrine and metabolic actions of GH secretagogues: interaction with GHRH. Clin Endocrinol (Oxf). 1996/1997 reviews. PubMed: https://pubmed.ncbi.nlm.nih.gov/9012467/

 

Disclaimer: For research background only. Not medical advice. Combined use of tesamorelin and ipamorelin is investigational; safety and efficacy for any clinical purpose have not been established.