Ipamorelin vs TB-500
An evidence-first, side-by-side comparison. We compare what the research supports — not marketing claims.
Last updated
Evidence grade
Animal
Animal
What that means
Preclinical evidence from animal models only — not yet shown in humans.
Preclinical evidence from animal models only — not yet shown in humans.
Status
Research compound
Research compound
Mechanism
Ipamorelin is a synthetic pentapeptide ghrelin mimetic that binds the growth hormone secretagogue receptor (GHSR-1a) and tells the pituitary to release GH. Selectivity is its calling card. Where GHRP-2 and GHRP-6 drag cortisol and ACTH up alongside GH, ipamorelin — in animal studies — lifts GH without significantly moving ACTH or cortisol beyond what GHRH itself does. It also barely touches appetite compared to MK-677, a difference that comes down to how it sits on the receptor. In animal work it usually shares the syringe with a GHRH analog like CJC-1295, the idea being that hitting the GHRH receptor and the GHSR at once amplifies the GH pulse more than either alone.
Marketed as a synthetic form of thymosin β-4 (Tβ4), a peptide the body makes that binds and regulates actin — one of the core building blocks of the cell skeleton. Shift actin dynamics and you influence how cells migrate, how new vessels form, and how inflammation settles at an injury, at least in animal models. One wrinkle the labels rarely mention: much of what is sold as "TB-500" is actually a shorter fragment of Tβ4, not the full molecule used in clinical research. We cover that fragment separately.
Goals
GH / IGF-1 support, Body composition
Tendon & ligament repair, Muscle recovery
Key risks
- No published human RCTs — all evidence is preclinical; human efficacy and safety are unestablished
- Sold for research use only; purity and dosing accuracy depend entirely on the supplier
- Unknown long-term effects in humans
- Consumer "TB-500" is often a fragment, not the clinically studied full peptide
- No completed human RCTs demonstrating the benefits people seek for injuries
- Pro-angiogenic activity is a theoretical concern in people with cancer
Regulatory
Sold "for research use only" — not approved for human consumption.
Sold "for research use only" — not approved for human consumption.