TB-500 (Ac-LKKTETQ)
Thymosin Beta-4 Active Fragment · Healing Peptide
TB-500 (Ac-LKKTETQ) is a synthetic derivative of thymosin beta-4 consisting of the N-terminal acetylated 17-23 amino acid fragment. This sequence represents the active site within thymosin beta-4 responsible for actin binding, cell migration, and wound healing. Research shows it promotes endothelial cell differentiation, angiogenesis, keratinocyte migration, collagen deposition, and decreases inflammation. The acetylation protects against N-terminal degradation while maintaining biological activity.
Overview
TB-500 (Ac-LKKTETQ) is a synthetic derivative of thymosin beta-4 consisting of the N-terminal acetylated 17-23 amino acid fragment. This sequence represents the active site within thymosin beta-4 responsible for actin binding, cell migration, and wound healing. Research shows it promotes endothelial cell differentiation, angiogenesis, keratinocyte migration, collagen deposition, and decreases inflammation. The acetylation protects against N-terminal degradation while maintaining biological activity.
TB-500 contains the LKKTETQ sequence which is the actin-binding motif of full-length thymosin beta-4. This fragment shares many properties of the parent protein regarding cell proliferation, differentiation, and migration. It promotes angiogenesis by upregulating VEGF expression and enhancing endothelial cell sprouting. The peptide undergoes serial cleavage at the C-terminus during metabolism, while the N-terminal acetylation provides protection from degradation.
Research indications
What the compound has been studied for, grouped by body system. Effect size is the reported magnitude where it was measured — not a recommendation.
Promotes dermal wound healing through the active LKKTETQ sequence.
Supports tissue repair comparable to full thymosin beta-4 in research.
Promotes keratinocyte migration and collagen deposition.
Promotes endothelial cell differentiation and new blood vessel formation.
Decreases inflammatory responses in damaged tissues.
A large effect in a weak study and a small effect in a strong one are different things. Effect size is never evidence of use in people.
- Class
- Acetylated heptapeptide
- Chain length
- 7 residues
- Molecular weight
- 844 Da
- Typical dose
- 2-2.5mg per injection
- Frequency
- 2x weekly (e.g., Monday and Thursday)
- Cycle length
- 4-6 weeks loading phase
- Storage
- Reconstituted: 2-8°C refrigerated
Molecular data
- Type
- Acetylated heptapeptide
- Molecular weight
- 844 Da
- Chain length
- 7 residues
Dosing reference
Doses reported in the literature and by suppliers. These are a record of what has been used in research — reference, never instruction.
| Context | Route | Amount | Frequency |
|---|---|---|---|
| Loading phase | SubQ | 2-2.5 mg | 2x weekly for 4-6 weeks |
| Maintenance | SubQ | 2 mg | Weekly or bi-weekly |
Interactions
Commonly combined for enhanced healing effects through different mechanisms.
TB-500 is the active fragment; combining may be redundant.
Both support wound healing and tissue repair through different pathways.
Different mechanisms; may complement for tissue growth.
Quality checklist
- ✓White lyophilized powder
- ✓Clear solution after reconstitution
- ✓High purity (>98%)
- ✓Intact vacuum seal
- !Not authorized for human use
- !Research chemical only
- ×Discoloration
- ×Cloudy solution
- ×Particulates visible
What to expect
Safety
- Injection site reactions
- Mild fatigue
- Head rush (reported)
- Allergic reactions
- Unusual swelling or inflammation
- Not authorized for medicinal use
- Active cancer (theoretical concern)
- Pregnancy or breastfeeding
- Prohibited by WADA in sports
FAQ
Is TB-500 fragment (Ac-LKKTETQ) the same as full TB-500?
TB-500 fragment is the active 7-amino-acid sequence (LKKTETQ) of the larger 43-amino-acid thymosin beta-4. Both promote wound healing and cell migration, but the fragment is more stable due to N-terminal acetylation and may be more cost-effective while retaining core regenerative properties.
How quickly does TB-500 fragment accelerate wound healing?
Initial wound healing acceleration appears within 1-7 days, with enhanced cell migration and angiogenesis noticeable by week 1-2. Visible tissue repair improvements typically develop over 2-4 weeks during the loading phase of 2x weekly injections.
Should TB-500 fragment be used with BPC-157 for better healing?
Yes, TB-500 fragment and BPC-157 are commonly combined for synergistic healing. TB-500 promotes cell migration and angiogenesis while BPC-157 upregulates growth factors - together they address multiple healing pathways better than either peptide alone.
Is the N-terminal acetylation in TB-500 fragment necessary for effectiveness?
Yes, the acetylation protects the peptide from degradation at the N-terminus during metabolism while maintaining the active LKKTETQ sequence responsible for wound healing. This modification extends the functional lifespan and improves stability versus non-acetylated versions.