Tesamorelin + Ipamorelin is a 2:1 co-lyophilized blend of a stabilised full-length GHRH analogue and a selective ghrelin-receptor pentapeptide. What distinguishes it from other growth hormone blends is the GHRH side: tesamorelin is a 44-residue analogue of the complete human GHRH sequence carrying an N-terminal trans-3-hexenoyl group, and it is the only GHRH-side molecule in this class with an approved prescription reference product and a published Phase 3 evidence base — in visceral adipose tissue reduction in HIV-associated lipodystrophy. That approval belongs to the prescription medicine, not to research-grade material, and the distinction runs through everything below.
MyPeptide supplies Tesamorelin + Ipamorelin as a co-lyophilized powder in 15 mg (10 mg/5 mg) and 30 mg (20 mg/10 mg) vials within the growth hormone blends range. Research use only; not for human or veterinary use.
What is in the vial
| Component | Tesamorelin | Ipamorelin |
|---|---|---|
| Class | Stabilised full-length GHRH analogue | Growth hormone secretagogue, GHS-R1a agonist |
| Receptor | GHRH receptor (GHRH-R) | Ghrelin receptor (GHS-R1a) |
| Structure | trans-3-hexenoyl-modified human GHRH(1-44), 44 residues, C-terminal amide | Aib-His-D-2-Nal-D-Phe-Lys-NH2, 5 residues, C-terminal amide |
| CAS number | 218949-48-5 | 170851-70-4 |
| Molecular formula | C221H366N72O67S | C38H49N9O5 |
| Molecular weight | 5,135.86 g/mol | 711.85 g/mol |
| Blend ratio | 2:1 by mass — 15 mg (10/5) and 30 mg (20/10) | |
Origin and structure of the two components
Tesamorelin reproduces the full 44-residue human growth hormone releasing hormone sequence rather than the 29-residue active fragment used by sermorelin and the CJC-1295 family. Its single modification is chemical rather than sequence-level: a trans-3-hexenoyl group attached at the N-terminus. That acyl cap protects the peptide's most vulnerable point — the Tyr1-Ala2 bond cleaved by dipeptidyl peptidase-4 — without substituting any residue, so the molecule stays sequence-identical to native GHRH along its whole length. Our tesamorelin explainer covers the chemistry in full, and the trade-offs against the shorter native fragment are set out in tesamorelin vs sermorelin.
Ipamorelin is a synthetic pentapeptide from Novo Nordisk's 1990s secretagogue programme, built on aminoisobutyric acid and D-2-naphthylalanine residues. Its defining published property is selectivity: preclinical and human pharmacology work reported growth hormone release without the concurrent cortisol, ACTH and prolactin elevations characteristic of GHRP-2, GHRP-6 and hexarelin. Detail is in our ipamorelin explainer.
How the combination is thought to work
The pairing rests on two receptors on the same pituitary cell using different second-messenger systems. The GHRH receptor is Gs-coupled, so agonism raises cAMP and activates protein kinase A. The ghrelin receptor is Gq-coupled, driving phospholipase C, inositol trisphosphate and a rise in intracellular calcium. Human and animal pharmacology studies combining a GHRH-class and a GHRP-class compound have consistently reported a greater secretory response than either produces alone, and secretagogues at GHS-R1a have additionally been described as blunting somatostatin tone, which would permit a fuller GHRH-driven response.
Two design constraints follow from the specific formulation. First, the 2:1 mass ratio is not a 2:1 molar ratio: at 5,135.86 against 711.85 g/mol, ten milligrams of tesamorelin is about 1.95 µmol while five milligrams of ipamorelin is about 7.02 µmol — roughly 3.6 moles of ipamorelin per mole of tesamorelin. Second, a co-lyophilized product fixes that proportion; varying it requires separate vials of Tesamorelin and Ipamorelin. Our guide to peptide blends versus single vials works through when each format fits.
What the research has examined
Visceral adipose tissue and the approved indication
Tesamorelin has the strongest human evidence base of any GHRH-side molecule in this class. Phase 3 trials in people with HIV-associated lipodystrophy reported reductions in visceral adipose tissue measured by CT, with associated changes in triglycerides and IGF-1, and led to approval of the prescription product. Those data describe the prescription medicine administered under medical supervision; they are not evidence about research-grade material or about this blend.
Liver fat and metabolic endpoints
Later investigator-led studies examined hepatic fat fraction and related metabolic markers in the same population, again with the approved product. This literature is why tesamorelin appears in metabolic research contexts rather than only in growth-axis ones.
Combined GHRH and secretagogue pharmacology
The rationale for pairing is supported by a separate and older literature in which GHRH was administered alongside a GHRP-class secretagogue in humans and animals, reporting synergy at the pituitary. This work generally used native GHRH or sermorelin rather than tesamorelin.
Ipamorelin selectivity work
Preclinical comparisons against GHRP-6 established that ipamorelin releases growth hormone without the associated ACTH and cortisol response, which is why it is the secretagogue used in most current blends.
What has not been studied
There are no published controlled studies of this co-formulated product, and no evidence establishing that a 2:1 mass ratio is optimal for any research question. Blend composition is a formulation convention.
Forms and sizes we supply
Both presentations are co-lyophilized into a single vial, so one reconstitution yields a solution containing both peptides in the stated proportion. The 15 mg (10 mg/5 mg) vial suits shorter series; the 30 mg (20 mg/10 mg) vial is the more economical unit where an extended study should run on a single lot. Each lot is supplied with a certificate reporting purity per component at ≥99% by HPLC. Where the research question concerns the approved product rather than the research compound, the reference listing is Tesamorelin (Egrifta-type), which is a prescription-only biologic.
Reconstitution and storage in a lab context
The blend reconstitutes as one material. Bacteriostatic water is used where the vial will be drawn from repeatedly, sterile water where a preservative would interfere with an assay. Solvent goes down the vial wall and the vial is swirled, not shaken — tesamorelin is a 44-residue peptide and agitation adds foam and surface denaturation without speeding dissolution.
The arithmetic must be handled per component, because this blend is not 1:1. A 15 mg (10/5) vial made up with 2 mL of diluent gives 7.5 mg/mL total, which resolves to 5 mg/mL of tesamorelin and 2.5 mg/mL of ipamorelin; 0.1 mL — the 10-unit mark on a U-100 syringe — therefore contains 500 mcg of tesamorelin and 250 mcg of ipamorelin. Reading the total as though it were a single peptide is the most common blend arithmetic error. The method is set out in our reconstitution guide.
Lyophilized vials are held at −20 °C, sealed and protected from light and moisture; reconstituted solution at 2–8 °C for the study window, with aliquoting and freezing for longer work. General practice is in how to store peptides.
Purity, COA and how to read a blend certificate
A two-component certificate has to answer what is in the vial and in what proportion. Purity should be reported for each peptide separately rather than as one combined figure. Mass spectrometry should show both expected masses — 5,135.86 g/mol and 711.85 g/mol — which is a far stronger identity check than either alone, and the large mass difference makes the two peaks easy to resolve. The HPLC trace should show two well-separated peaks whose relative areas are consistent with a 2:1 mass blend; a single peak, or a ratio that does not match the label, is a reason to query the lot before use.
Regulatory status
This is the point where tesamorelin differs from most research peptides. An approved prescription product containing tesamorelin exists in the United States for a specific indication, and it is a prescription-only biologic supplied through pharmacy channels under medical supervision. The research-grade blend on this page is not that product, is not equivalent to it, and carries none of its approvals. Ipamorelin has no marketing authorisation anywhere. Material supplied here is a research-use-only chemical for laboratory investigation by qualified personnel — not a supplement, not a medicine, and not for human or veterinary administration. GHRH analogues and growth hormone secretagogues are prohibited in sport under anti-doping rules.
Related blends and further reading
The nearest alternatives keep ipamorelin and change the GHRH-side partner: CJC-1295 (No DAC) + Ipamorelin uses a four-substitution 29-residue analogue at a 1:1 ratio, and Sermorelin + Ipamorelin uses the unmodified native GHRH (1-29) fragment.