What Are Ipamorelin and Tesamorelin?
These are two distinct but complementary peptides in the growth hormone optimization space. They work through different receptor pathways but are often discussed together because of their synergistic potential.
Side-by-Side Comparison
| Property | Ipamorelin | Tesamorelin |
|---|---|---|
| Type | Growth Hormone Secretagogue (GHS) | GHRH Analog |
| Amino Acids | 5 | 44 |
| Molecular Weight | ~711 Da | ~5,136 Da |
| Mechanism | Mimics ghrelin at pituitary | Stimulates GHRH receptors |
| Half-Life | ~2 hours | ~26 minutes |
| FDA Approved | No | Yes (Egrifta, for HIV lipodystrophy) |
| Category 1 Expected | Yes | N/A (already FDA-approved) |
| GH Release Pattern | Pulsatile | Sustained |
| Selectivity | Very high (no cortisol/prolactin spike) | High |
How They Work Together: The "Push-Pull" Effect
Ipamorelin and tesamorelin activate different receptor pathways to amplify growth hormone output:
| Peptide | Receptor | Action |
|---|---|---|
| Tesamorelin | GHRH receptors | Tells the pituitary to make more GH |
| Ipamorelin | Ghrelin/GHS receptors | Tells the pituitary to release GH |
| Combined | Both pathways | Amplified GH output beyond either alone |
The Ipamorelin + CJC-1295 stack is the most commonly prescribed peptide combination in clinical practice. The Ipamorelin + Tesamorelin combination is less common but offers the advantage of tesamorelin's FDA-approval backing.
Research Areas of Interest
Ipamorelin
- Selectivity — stimulates GH without spiking cortisol, prolactin, or ACTH
- Versatility — pairs well with GHRH analogs (CJC-1295 or tesamorelin)
- Tolerability — fewer reported side effects than older GHSs like GHRP-6
Tesamorelin
- FDA-approved — one of very few peptides with robust human clinical trial data
- Visceral fat reduction — clinically demonstrated to reduce trunk/abdominal fat
- Cognitive research — emerging studies on neuroprotective effects
- IGF-1 elevation — produces significant, sustained increases
Regulatory Status
| Peptide | FDA Status | Pharmacy Availability | Notes |
|---|---|---|---|
| Ipamorelin | Not approved | Compounding pharmacy (Rx) | Expected Category 1 reclassification |
| Tesamorelin | Approved (Egrifta / Egrifta WR) | Specialty + compounding pharmacy | Egrifta WR received additional FDA approval March 2025; off-label prescribing common |
How They're Sold
| Source | Ipamorelin | Tesamorelin |
|---|---|---|
| Research Vendors | $20-45/2mg vial (common) | $50-100+/vial (limited) |
| Compounding Pharmacy | $100-250/month | $200-500+/month |
| CJC/Ipa Combo (pharmacy) | $200-450/month | N/A |
| Egrifta Brand | N/A | $1,000+/month (specialty) |
What to Look For on the COA
Ipamorelin
- HPLC purity — 98%+ required
- Mass spectrometry — confirm MW of ~711 Da
- Endotoxin testing — standard for injectable forms
- For combo vials: verify both peptides are listed and tested on the COA
Tesamorelin
- HPLC purity — 98%+ required
- Mass spectrometry — confirm MW of ~5,136 Da
- Endotoxin testing — essential for injectable forms
Tesamorelin is a complex 44-amino-acid molecule. Synthesis errors and degradation are more common than with simpler peptides. Always verify mass spec data, and prefer compounding pharmacy sources over gray market vendors for this peptide.
Storage Guide
| Form | Temperature | Shelf Life | Special Notes |
|---|---|---|---|
| Lyophilized (either) | 2-8°C | Months | Standard refrigeration |
| Reconstituted (either) | 2-8°C | 21 days | Use promptly |
| Tesamorelin specifically | 2-8°C | Per label | Particularly temperature-sensitive |
- Protect both peptides from light
- Tesamorelin degrades faster than ipamorelin — do not leave unrefrigerated
Key Sourcing Tips
- Ipamorelin is widely available and well-characterized — source from vendors with published COAs or a licensed compounding pharmacy
- Tesamorelin is complex to synthesize — prefer compounding pharmacy sources over gray market vendors
- For combination stacks, pre-mixed Ipa/CJC or Ipa/Tesamorelin vials from pharmacies offer the best convenience and quality assurance
- If prescribed Egrifta (brand tesamorelin), use a specialty pharmacy experienced with the product
- Always verify molecular weights on COAs — both peptides are frequently counterfeited or substituted with cheaper alternatives