Head-to-head
TB-500 vs Ipamorelin
A field-by-field comparison of TB-500 and Ipamorelin drawn from the PeptideIndex database: mechanism, evidence grade, half-life, administration route, reported dosing, side effects, storage and legal status. They belong to different categories — recovery & repair and growth hormone — so this page focuses on what each one actually does rather than which is "better".
TB-500 vs Ipamorelin at a glance
| Attribute | TB-500 | Ipamorelin |
|---|---|---|
| Category | Recovery & repair | Growth hormone |
| Evidence grade | Emerging | Moderate |
| Also known as | Thymosin Beta-4 fragment, TB4 | NNC 26-0161 |
| Chain | 7 amino acids (actin-binding domain of Tβ4) | Pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) |
| Mechanism | Binds G-actin and promotes actin polymerisation, which drives cell migration into damaged tissue. It also stimulates endothelial cell differentiation and new capillary growth, and downregulates inflammatory cytokines. | Acts as a ghrelin receptor (GHS-R1a) agonist on the pituitary, triggering a clean GH pulse. Its selectivity avoids the appetite and cortisol effects seen with older secretagogues like GHRP-6. |
| Reported benefits | Improved cell migration and wound closure in animal studies · Reported flexibility gains and reduced muscle spasm · Systemic action rather than site-specific, unlike BPC-157 | Clean GH pulse without hunger spikes · Better sleep quality and recovery · Mild fat-loss and body-composition support |
| Reported side effects | Fatigue or head-rush after dosing · Injection-site reaction · Theoretical tumour-growth concern given angiogenic activity | Mild headache · Injection-site redness · Light-headedness shortly after dosing |
| Half-life | Roughly 2–3 hours, with tissue effects lasting far longer | About 2 hours |
| Administration | Subcutaneous or intramuscular injection | Subcutaneous injection, 1–3 times daily |
| Dosing overview | Loading phase of 2–5 mg twice weekly for 4–6 weeks, then a lower maintenance dose | 200–300 mcg per dose, often 100–300 mcg before bed |
| Storage | Powder at room temperature short term; reconstituted 2–8 °C for up to 30 days | Reconstituted vials refrigerated 2–8 °C, stable ~4 weeks |
| Legal status | Not approved for human use; sold for research purposes only. | Not FDA-approved; compounding restrictions apply in the US. Banned in sport. |
Key differences between TB-500 and Ipamorelin
Different categories, different goals
TB-500 is indexed under recovery & repair, while Ipamorelin sits under growth hormone. They are not substitutes for one another: TB-500 is described as "A synthetic version of the active region of thymosin beta-4, a naturally occurring wound-healing protein present in nearly all human cells." and Ipamorelin as "The most selective of the growth-hormone secretagogues, valued because it lifts GH without meaningfully raising cortisol or prolactin."
Mechanism of action
TB-500: Binds G-actin and promotes actin polymerisation, which drives cell migration into damaged tissue. It also stimulates endothelial cell differentiation and new capillary growth, and downregulates inflammatory cytokines. Ipamorelin: Acts as a ghrelin receptor (GHS-R1a) agonist on the pituitary, triggering a clean GH pulse. Its selectivity avoids the appetite and cortisol effects seen with older secretagogues like GHRP-6.
Evidence quality is not equal
TB-500 carries a Emerging evidence grade and Ipamorelin a Moderate grade on this index. The grade describes the quality of published human data, not how well a compound works — Ipamorelin has the better-documented record of the two, and claims made about TB-500 rest on thinner human evidence.
Half-life and dosing frequency
TB-500 is listed at roughly 2–3 hours, with tissue effects lasting far longer; Ipamorelin at about 2 hours. That difference is what drives the reported schedules: Loading phase of 2–5 mg twice weekly for 4–6 weeks, then a lower maintenance dose versus 200–300 mcg per dose, often 100–300 mcg before bed
Route of administration
TB-500 is administered by subcutaneous or intramuscular injection. Ipamorelin is administered by subcutaneous injection, 1–3 times daily.
Legal and regulatory status differs
TB-500: Not approved for human use; sold for research purposes only. Ipamorelin: Not FDA-approved; compounding restrictions apply in the US. Banned in sport. This is usually the most practical difference between two compounds, because it determines whether a supply chain is labelled and regulated at all.
Handling and storage
TB-500 is stored powder at room temperature short term; reconstituted 2–8 °c for up to 30 days. Ipamorelin is stored reconstituted vials refrigerated 2–8 °c, stable ~4 weeks.
What TB-500 and Ipamorelin have in common
On the attributes tracked in this database — category, evidence grade, mechanism, half-life, administration, dosing overview, storage and legal status — TB-500 and Ipamorelin share no identical values. They are compared here because they come up together in the same searches, not because they overlap.
Each compound in brief
TB-500
Recovery & repair · Emerging evidence
A synthetic version of the active region of thymosin beta-4, a naturally occurring wound-healing protein present in nearly all human cells.
Considerations: Frequently stacked with BPC-157 in anecdotal recovery protocols · Human data is limited to Tβ4 trials in dry-eye and cardiac injury · Prohibited by WADA at all times
Ipamorelin
Growth hormone · Moderate evidence
The most selective of the growth-hormone secretagogues, valued because it lifts GH without meaningfully raising cortisol or prolactin.
Considerations: Weakest GH release of the GHRPs — usually stacked with CJC-1295 · Effects build over weeks, not days · Dose ceiling: more than ~300 mcg per pulse gives diminishing returns
Related comparisons and reading
Every figure on this page is reproduced from the compound profiles in this database and reflects published literature and commonly reported protocols. It is educational information, not medical advice, and not a recommendation to use either compound. See the medical disclaimer.