Loading the comparison…
Loading the comparison…
Recovery & Repair
Synthetic fragment of thymosin beta-4, used for whole-body recovery.
Immune
Immune-modulating peptide approved in dozens of countries.
TB-500 is not FDA-approved and rated 2/5 for evidence; Thymosin Alpha-1 is not FDA-approved and rated 4/5. Thymosin Alpha-1 has more human evidence behind it. TB-500 is banned in sport by WADA; Thymosin Alpha-1 is not. TB-500 is listed under Recovery & Repair; Thymosin Alpha-1 under Immune.
| Compare | TB-500 Synthetic fragment of thymosin beta-4, used for whole-body recovery. | Thymosin Alpha-1 Immune-modulating peptide approved in dozens of countries. |
|---|---|---|
| Category | Recovery & Repair | Immune |
| Evidence | 2/5Full-length Tβ4 has some human trials (eye, wound); TB-500 fragment is mostly animal and anecdotal. | 4/5Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral). |
| FDA status | Not FDA-approved | Not FDA-approved (approved in ~35 other countries) |
| WADA (sport) | Banned | Not on the Prohibited List |
| Also known as | Thymosin Beta-4 fragment, Tβ4 (Ac-SDKP / LKKTETQ region) | Tα1, Thymalfasin, Zadaxin |
| How it works | Binds actin, helping cells migrate to injured tissue; promotes angiogenesis and reduces inflammation in models. Full-length thymosin beta-4 has been studied in dry eye and wound healing trials; the TB-500 fragment itself has little human data. | Enhances T-cell maturation and dendritic cell function, modulating innate and adaptive immunity. |
| Half-life | Not well characterized; dosed twice weekly by convention | About 2 hours |
| Commonly reported doses |
|
|
| Route | Subcutaneous | Subcutaneous |
| Good once mixed | ~28 days in the fridge | ~14 days in the fridge |
| Top side effects |
|
|
| Lowest research-listing price per mg | $2.40 (10 mg vial, 40% off) | $2.40 (10 mg vial, 40% off) |
| Latest lab purity | 99.51% (lot TB0002) | 99.92% (lot THA0001) |
Want a third? Add another peptide. Doses are commonly reported ranges, not recommendations.
Free for ChatGPT and Claude
Connect MyPeps to ChatGPT or Claude and ask follow-ups about TB-500 and Thymosin Alpha-1. It answers from these same pages, with links back here.
TB-500 is not FDA-approved and rated 2/5 for evidence; Thymosin Alpha-1 is not FDA-approved and rated 4/5. Thymosin Alpha-1 has more human evidence behind it. TB-500 is banned in sport by WADA; Thymosin Alpha-1 is not. TB-500 is listed under Recovery & Repair; Thymosin Alpha-1 under Immune.
TB-500: Not FDA-approved. Thymosin Alpha-1: Not FDA-approved (approved in ~35 other countries). Regulations change, so confirm with the FDA.
TB-500 is rated 2 out of 5: Full-length Tβ4 has some human trials (eye, wound); TB-500 fragment is mostly animal and anecdotal. Thymosin Alpha-1 is rated 4 out of 5: Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral). The scale is explained on our methodology page.
TB-500 is banned by WADA, by name or as part of a named class. Thymosin Alpha-1 is not named on the WADA list, though the general rule on non-approved substances (S0) can still apply.