What Is TB-500?
TB-500 is a synthetic peptide corresponding to the active region (amino acids 17-23) of Thymosin Beta-4, a naturally occurring protein found in virtually all human and animal cells. The full Thymosin Beta-4 protein has 43 amino acids, but TB-500 specifically refers to the shorter active fragment that is most commonly sold by research vendors and compounding pharmacies.
Important distinction: TB-500 (the fragment, ~889 Da) and full-length Thymosin Beta-4 (~4,921 Da) are different products. Most vendors sell the TB-500 fragment. Always check the molecular weight on your COA to confirm which one you're receiving.
Quick Facts
| Property | Detail |
|---|---|
| Full Name | Thymosin Beta-4 fragment (Ac-LKKTETQ) |
| Molecular Weight | ~889 Da (TB-500 fragment) |
| Amino Acids | 7 (fragment); 43 (full Thymosin Beta-4) |
| Sequence | Ac-LKKTETQ (amino acids 17-23 of TB-4) |
| Regulatory Status | Expected Category 1 reclassification |
| Common Pairing | BPC-157 (complementary mechanisms) |
Research Areas of Interest
- Tissue repair — promotes healing of muscles, tendons, and ligaments
- Anti-inflammation — may reduce inflammatory markers at injury sites
- Angiogenesis — supports growth of new blood vessels to damaged areas
- Cell migration — helps recruit repair cells to sites of injury
- Hair regrowth — some research suggests follicle stimulation properties
The BPC-157 + TB-500 Stack
This is one of the most common peptide pairings in both research and clinical settings:
| Peptide | Primary Mechanism | Scope |
|---|---|---|
| BPC-157 | Localized GI and connective tissue repair | Targeted, local |
| TB-500 | Systemic recovery and cell migration | Broad, systemic |
| Combined | Complementary repair pathways | Both local and systemic |
How It's Sold
| Source | Form | Prescription? | Typical Cost |
|---|---|---|---|
| Research Vendors | Lyophilized powder (5mg vial) | No | $35-70/vial |
| Research Vendors | Pre-mixed solution | No | $45-80/vial |
| Compounding Pharmacy | Injectable (subcutaneous) | Yes | $150-350+/month |
| Compounding Pharmacy | BPC-157/TB-500 combo vial | Yes | $200-400+/month |
Regulatory Status
TB-500 / Thymosin Beta-4 is among the 14 peptides expected to be reclassified to Category 1 under the RFK announcement. Once finalized:
- Licensed compounding pharmacies can legally compound it
- A valid prescription from a licensed provider will be required
- All compounded products must meet USP quality standards
What to Look For on the COA
- HPLC purity — minimum 95%, preferably 98-99%+
- Mass spectrometry — confirm MW matches what you ordered: ~889 Da for TB-500 fragment, ~4,921 Da for full-length Thymosin Beta-4
- Endotoxin testing — critical for injectable forms
- Appearance — should be white to off-white lyophilized powder
Storage Guide
| Form | Temperature | Shelf Life |
|---|---|---|
| Lyophilized (powder) | Room temp OK; 2-8°C ideal | Months to years |
| Reconstituted | 2-8°C (refrigerate immediately) | 14-21 days |
- Protect from light and avoid repeated freeze/thaw cycles
Key Sourcing Tips
- Always verify the COA matches the specific batch you received
- For research: choose US-based vendors with published third-party testing from named labs
- For personal use: work with a licensed provider and compounding pharmacy
- The BPC-157 + TB-500 combination is widely available from both vendor and pharmacy channels
- Avoid any source making therapeutic claims or providing human dosing guidance