Tesamorelin + Ipamorelin: Two Receptor Arms, and What Was Never Studied

What is the tesamorelin + ipamorelin blend?

It is a research preparation supplying two synthetic peptides of very different size and origin in a single vial. The supplier’s own listings describe it as tesamorelin 10 mg with ipamorelin 5 mg. As with every blend in this catalogue, that ratio is a packaging specification: no published work establishes any ratio between these two molecules as meaningful.

• Tesamorelin — a synthetic 44-residue analogue of growth-hormone-releasing hormone, stabilised against the enzyme DPP-4 by an N-terminal modification. It is a GHRH-receptor agonist and it is the active molecule in an approved medicine. Full detail on the tesamorelin research page.
• Ipamorelin — a pentapeptide, Aib-His-D-2-Nal-D-Phe-Lys-NH₂, acting at the ghrelin receptor (GHS-R1a) and not at the GHRH receptor. Never approved for any indication. Full detail on the ipamorelin research page.

The catalogue contains a second two-peptide preparation from this same pharmacological space: CJC-1295 with ipamorelin, which pairs a different GHRH analogue with the same secretagogue. Composition-wise the two preparations are analogous; evidence-wise neither is evidence for the other, and each is covered on its own page.

Reference data — per component

Given per component, from the public chemical record. Tesamorelin’s full 44-residue sequence is documented in the regulatory literature; it is not reproduced here in full, and the identifying fields below are the ones that could be sourced.

The seven-fold difference in molecular weight is the practical headline of this table. A 5.1 kDa peptide and a 712 Da pentapeptide are different analytical objects: they need different chromatographic conditions, they ionise differently in mass spectrometry, and they are not interchangeable in any method. The verification section returns to what that means for a certificate.

Two receptor arms — what is actually established

The claim that these two molecules act through different receptors is not an inference; it was demonstrated directly. Raun et al. (1998, Eur J Endocrinol), the paper that introduced ipamorelin, profiled the compound against both GHRP and GHRH antagonists and reported that ipamorelin, like GHRP-6, stimulates growth-hormone release via a GHRP-like receptor — the receptor now known as GHS-R1a. Tesamorelin, by contrast, is a GHRH analogue acting at the GHRH receptor.

Raun et al. also reported the selectivity finding ipamorelin is known for. In swine, none of the secretagogues tested affected FSH, LH, prolactin or TSH, but GHRP-6 and GHRP-2 both raised ACTH and cortisol, whereas ipamorelin did not do so at levels significantly different from GHRH stimulation — even at doses more than 200-fold above its ED₅₀ for GH release. The authors describe it as the first GHRP-receptor agonist with a selectivity for GH release similar to that of GHRH. That is a characterisation of one molecule in one animal model, reported here as such.

What the distinctness of the two receptors establishes is narrow and worth stating precisely: it means that engaging both is not the same experiment as engaging either one, and therefore that a combination is a legitimate research question. It does not establish an answer to that question. A page that moves from “different receptors” to “therefore better together” has substituted a mechanism sketch for a measurement, and no measurement of this pair exists.

What each component's own literature investigated

Tesamorelin

Tesamorelin has the more substantial clinical record of the two, built almost entirely in one population. Falutz et al. (2007, NEJM) reported a randomised trial of the growth-hormone-releasing factor in patients with HIV and excess abdominal fat; Falutz et al. (2010, JCEM) published a pooled analysis of two multicentre, double-blind, placebo-controlled phase 3 trials in the same setting. Later work extended into hepatic endpoints: Stanley et al. (2019, Lancet HIV) reported a randomised, double-blind, multicentre trial of tesamorelin in non-alcoholic fatty liver disease in HIV. Egrifta was approved in 2010 for a specific indication in that population. See the tesamorelin page.

Ipamorelin

Ipamorelin’s development took a direction that surprises most readers: its published clinical work is not about growth hormone at all. Venkova et al. (2009, J Pharmacol Exp Ther) examined it in a rodent model of postoperative ileus, and Beck et al. (2014, Int J Colorectal Dis) reported a prospective, randomised, controlled proof-of-concept study of the ghrelin mimetic for the management of postoperative ileus in bowel-resection patients. It was never approved, for that or any other indication. See the ipamorelin page.

The asymmetry between these two records matters when reading anything about the pair. One component has phase 3 trials and an approval in a narrow indication; the other has a phase 2 study in an unrelated field and no approval. Any informal reasoning from “both are well studied” is already inaccurate before the combination question is even reached.

Combined GHRH + secretagogue research: what exists, and what does not

This section is the reason the page needs care, because unlike the catalogue’s other blends there is a real body of co-administration literature here — it simply does not involve these two molecules.

What does exist (other pairs)

• Combined GHRH + GHRP as a diagnostic test. Mahajan and Lightman (2000, JCEM) evaluated the GH-releasing effect of GHRH combined with a small dose of GHRP-2 as a test for growth-hormone deficiency in adults, comparing it against the insulin tolerance test in 36 patients with hypothalamic/pituitary disease and 30 healthy volunteers. The purpose was diagnostic — provoking a measurable response to classify patients — not therapeutic.
• Combined long-term treatment in an animal model. Fintini et al. (2005, Neuroendocrinology) treated GHRH-knockout mice for five weeks with the GHRH analogue JI-38 alone or in combination with GHRP-2. The paper opens by stating plainly that it is not known whether combined treatment with GHRH and GHS has synergistic effects on growth — the question was open in 2005 and was being asked for the first time in that model. The authors reported that animals receiving both reached greater body length and weight than those receiving the GHRH analogue alone, and that GHRH-knockout animals showed no GH response to GHRP-2 alone while both treated groups responded to the combined stimulus, concluding that the presence of GHRH appears necessary for GHRP-2 to stimulate GH secretion.

What does not exist (this pair)

In July 2026 the following searches were run. PubMed for tesamorelin AND ipamorelin: six records, all narrative or systematic reviews of the peptide market that discuss each compound separately. Europe PMC for both terms anywhere in the record, which additionally covers preprints: fifteen records of the same character, plus unrelated matches. ClinicalTrials.gov for tesamorelin AND ipamorelin: zero registered studies.

So the honest position is this: no study of tesamorelin with ipamorelin exists. The co-administration literature above used different molecules — JI-38 and GHRP-2 in a knockout mouse; GHRH with GHRP-2 in a diagnostic protocol — in different settings, for different purposes. Fintini et al. tested a specific GHRH analogue with a specific secretagogue in a specific genetic model; their finding belongs to that experiment. Extending it to a tesamorelin-and-ipamorelin vial would require assuming that one GHRH analogue behaves like another, that one secretagogue behaves like another, and that a knockout-mouse growth model transfers — three assumptions, none tested, compounding.

Combining these two peptides in one vial is therefore a supplier packaging decision. This page makes no claim about the pair, offers no comparison between the preparation and either component alone, and does not treat the general GHRH/GHS principle as though it were a finding about this product. What can be said is that a study of this pair would be a reasonable thing for someone to do, and that nobody has.

Evidence status and what is not established

What is established: two molecules with characterised receptor pharmacology, one demonstrated by antagonist profiling to act at a GHRP-like receptor rather than the GHRH receptor; a phase 3 clinical record and an approval for tesamorelin in a narrow indication; a phase 2 record for ipamorelin in an unrelated indication; and a small co-administration literature covering other GHRH-analogue and secretagogue pairs, in diagnostic and animal-model settings.

What is not established: (1) anything about tesamorelin and ipamorelin administered together; (2) that findings from other GHRH/GHS pairs transfer to this one, for the reasons set out above; (3) any effect of ipamorelin on growth-hormone-related endpoints in humans beyond what its own limited literature reports; and (4) any property of research-grade supplied material, since every study named here used a manufactured pharmaceutical or a characterised laboratory reagent under experimental conditions.

Ipamorelin is approved by no regulator anywhere. Tesamorelin is the active molecule in an approved medicine — but supplied research material is not that medicine and inherits none of its regulatory status or clinical data. No combination of the two has been reviewed by any regulator. Material described here is a laboratory research reagent: not a medicine, not for human or veterinary use, with no dosing, preparation-for-use or administration guidance given.

How to verify this compound yourself

The analytical challenge here is the seven-fold size gap between the two components, which is unusual even among blends:

• One method rarely serves both well. A reversed-phase gradient tuned to elute and resolve a 5.1 kDa 44-residue peptide is not the same method that best characterises a 712 Da pentapeptide. A certificate that reports a single purity figure for the vial should state which component and which method it refers to; if it does not, the number cannot be interpreted.
• Two masses, two confirmations. Mass-spec identity should return both expected masses — approximately 5136 Da and approximately 711.9 Da. For tesamorelin the N-terminal trans-3-hexenoyl modification is the feature that distinguishes it from unmodified GHRH(1-44); its absence would shift the measured mass. Ipamorelin carries a C-terminal amide, a feature whose loss also produces a mass shift.
• Per-component content, not just purity. A vial specified as 10 mg + 5 mg needs two quantitation results. This is especially consequential at a seven-fold mass difference, where the smaller component contributes a modest share of the total material mass and can be substantially under-represented without an obvious signal.
• Endotoxin and sterility — where tested, independent quality attributes reported separately from chemical purity.

On the base rate for this class: a 2026 preprint by Mendias and Awan analysed 6,441 samples across fourteen compounds, tesamorelin and ipamorelin among them, from a large public independent-testing dataset. Between 41.6% and 71.1% failed basic quality criteria depending on which of two acceptance frameworks was applied, with measurable endotoxin in 15%. It is a preprint and has not completed peer review; it is cited because it is the largest published analysis of this exact material class.

See how to read a COA, how to verify peptide purity and how to spot a fake COA. Check the exact batch on the self-serve verify tool.

Research-grade sourcing and verification

This two-component preparation is not held in Cellworks stock. It appears in the sourcing catalogue as available to order; sourcing takes roughly two to three weeks, no price is quoted until availability is confirmed, and there is no cart button. Tesamorelin is also listed on its own, and Cellworks stocks a single-compound tesamorelin presentation.

Anything sourced is a laboratory research reagent with a per-batch Certificate of Analysis. For a two-component vial with a seven-fold size gap, per-component identity and content are the whole of the assurance.

Frequently asked questions

Literature cited

1. Raun K, Hansen BS, Johansen NL, et al. “Ipamorelin, the first selective growth hormone secretagogue.” Eur J Endocrinol. 1998;139(5):552–561. PMID 9849822. pubmed.ncbi.nlm.nih.gov/9849822. (Ipamorelin component; receptor profiling and selectivity.)
2. Beck DE, Sweeney WB, McCarter MD, et al. “Prospective, 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. 2014;29(12):1527–1534. PMID 25331030. pubmed.ncbi.nlm.nih.gov/25331030.
3. Venkova K, Mann W, Nelson R, Greenwood-Van Meerveld B. “Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus.” J Pharmacol Exp Ther. 2009;329(3):1110–1116. PMID 19289567. pubmed.ncbi.nlm.nih.gov/19289567.
4. Falutz J, Allas S, Blot K, et al. “Metabolic effects of a growth hormone-releasing factor in patients with HIV.” N Engl J Med. 2007;357(23):2359–2370. PMID 18057338. pubmed.ncbi.nlm.nih.gov/18057338. (Tesamorelin component.)
5. Falutz J, Mamputu JC, Potvin D, et al. “Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in HIV-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials.” J Clin Endocrinol Metab. 2010;95(9):4291–4304. PMID 20554713. pubmed.ncbi.nlm.nih.gov/20554713.
6. Stanley TL, Fourman LT, Feldpausch MN, et al. “Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trial.” Lancet HIV. 2019;6(12):e821–e830. PMID 31611038. pubmed.ncbi.nlm.nih.gov/31611038.
7. Fintini D, Alba M, Schally AV, Bowers CY, Parlow AF, Salvatori R. “Effects of combined long-term treatment with a growth hormone-releasing hormone analogue and a growth hormone secretagogue in the growth hormone-releasing hormone knock out mouse.” Neuroendocrinology. 2005;82(3–4):198–207. PMID 16601359. pubmed.ncbi.nlm.nih.gov/16601359. (A different GHRH analogue with a different secretagogue — not this pair.)
8. Mahajan T, Lightman SL. “A simple test for growth hormone deficiency in adults.” J Clin Endocrinol Metab. 2000;85(4):1473–1476. PMID 10770184. pubmed.ncbi.nlm.nih.gov/10770184. (Combined GHRH/GHRP-2 diagnostic test — not this pair.)
9. Mendias CL, Awan TM. “Evaluation of Research Grade Peptides Marketed Directly to Consumers Reveals Extensive Variability in Purity and Measured Abundance.” Preprints (not peer reviewed). 2026. doi.org/10.20944/preprints202604.1748.v1.
10. National Center for Biotechnology Information. “PubChem Compound Summary for CID 16137828, Tesamorelin” and “CID 9831659, Ipamorelin.” pubchem.ncbi.nlm.nih.gov/compound/16137828 · pubchem.ncbi.nlm.nih.gov/compound/9831659.