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Thymosin Beta-4 Fragment

Also known as: TB4-Frag, Ac-SDKP, N-Acetyl-Ser-Asp-Lys-Pro

Thymosin Beta-4 Fragment is a tetrapeptide derived from the N-terminal sequence of Thymosin Beta-4, primarily studied for its anti-inflammatory and tissue repair properties.

Last updated: February 16, 2026Reviewed by: Research Team

Thymosin Beta-4 Fragment is a 476.48 g/mol research peptide. Thymosin Beta-4 Fragment is a tetrapeptide derived from the N-terminal sequence of Thymosin Beta-4, primarily studied for its anti-inflammatory and tissue repair properties.

Also called: TB4-Frag, Ac-SDKP, N-Acetyl-Ser-Asp-Lys-Pro

476.48 g/mol

Molecular Weight

Daltons

2

Strong Evidence

benefits

4

Studies Cited

peer-reviewed

500-2000

Typical Dose

mcg

Overview

Thymosin Beta-4 Fragment represents a synthetic tetrapeptide sequence (Ac-SDKP) that corresponds to the first four amino acids of the naturally occurring Thymosin Beta-4 protein. This fragment retains many of the parent compound's beneficial properties while offering improved stability and targeted action. Research has focused on its role in modulating inflammatory responses, promoting angiogenesis, and supporting tissue regeneration processes. The acetylated N-terminal enhances the peptide's resistance to enzymatic degradation, making it a valuable research tool for studying wound healing mechanisms and anti-inflammatory pathways. Unlike the full-length Thymosin Beta-4, this fragment demonstrates more specific targeting of certain cellular pathways while maintaining a favorable safety profile in research applications.

Key Takeaways: Thymosin Beta-4 Fragment

  • Strongest evidence supports Thymosin Beta-4 Fragment for accelerated wound healing and anti-inflammatory effects
  • Research doses typically range from 500 to 2000 mcg via subcutaneous
  • 2 benefits with strong evidence, 3 moderate, 2 preliminary
  • Half-life: 4-6 hours
  • 4 cited research studies in this guide

Mechanism of Action

Thymosin Beta-4 Fragment works by binding to actin monomers and preventing their polymerization, which promotes cell migration and tissue repair. The peptide activates the PI3K/Akt pathway, leading to enhanced cell survival and proliferation. It stimulates angiogenesis through VEGF upregulation and promotes the migration of endothelial cells. The fragment also modulates inflammatory responses by inhibiting NF-κB activation and reducing pro-inflammatory cytokine production. Additionally, it influences matrix metalloproteinase activity, which plays a role in tissue remodeling and wound healing processes.

Research Benefits

Thymosin Beta-4 Fragment at a Glance

Primary mechanism:

Thymosin Beta-4 Fragment works by binding to actin monomers and preventing their polymerization, which promotes cell migration and tissue repair.

Top researched benefits:
Accelerated Wound HealingAnti-Inflammatory EffectsEnhanced AngiogenesisImproved Tissue RegenerationCardioprotective PropertiesNeuroprotective EffectsReduced Fibrosis

Accelerated Wound Healing

Strong Evidence

Promotes faster closure of skin wounds and tissue defects by enhancing cell migration and proliferation while stimulating collagen synthesis and angiogenesis

Anti-Inflammatory Effects

Strong Evidence

Reduces inflammatory markers and cytokine production, helping to resolve chronic inflammation and prevent excessive inflammatory responses

Enhanced Angiogenesis

Moderate Evidence

Stimulates the formation of new blood vessels through VEGF upregulation and endothelial cell migration, improving tissue perfusion and nutrient delivery

Improved Tissue Regeneration

Moderate Evidence

Supports the regeneration of various tissue types including muscle, skin, and cardiac tissue through enhanced cellular repair mechanisms

Cardioprotective Properties

Moderate Evidence

Demonstrates protective effects on cardiac tissue following injury, potentially reducing scarring and improving heart function recovery

Neuroprotective Effects

Preliminary

Shows potential in protecting neural tissue from damage and supporting recovery following brain or spinal cord injuries

Reduced Fibrosis

Preliminary

Helps prevent excessive scar tissue formation by modulating collagen deposition and promoting organized tissue repair

Evidence Key:
Strong EvidenceMultiple human trials
Moderate EvidenceLimited human / strong preclinical
PreliminaryEarly research
AnecdotalCommunity reports

Research Dosing Protocols

Research Purposes Only: All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.

Research ProtocolDose RangeRoute
General tissue repair5002000 mcgsubcutaneous
Wound healing studies10003000 mcgtopical/local injection
Anti-inflammatory research7502500 mcgsubcutaneous

Frequency

Once daily to twice daily

Timing

Morning or post-exercise for recovery studies

Cycle Length

4-8 weeks with 2-4 week breaks

Research Notes

  • 1Start with lower doses to assess tolerance
  • 2Injection site rotation recommended for subcutaneous administration
  • 3Some researchers divide daily dose into multiple injections
  • 4Effects may be cumulative over several weeks of administration

Reconstitution Guide

Standard Reconstitution

Vial Size

5 mg

Bacteriostatic Water

1 mL

Concentration

50 mcg

per 0.1 mL (10 units)

Step-by-Step Guide

1

Gather Materials

Thymosin Beta-4 Fragment vial, bacteriostatic water, alcohol swabs, insulin syringes.

2

Equilibrate Temperature

Remove the vial from storage and allow it to reach room temperature (5-10 minutes).

3

Sanitize

Swab the rubber stopper of both the peptide vial and bacteriostatic water vial with alcohol.

4

Draw Water

Draw 1 mL of bacteriostatic water into a syringe.

5

Add Water to Vial

Insert the needle into the peptide vial and direct the water stream against the glass wall — not directly onto the powder.

6

Mix Gently

Swirl the vial gently until the powder is fully dissolved. Never shake. The solution should be clear and colorless.

7

Store Properly

Refrigerate at 2-8°C (refrigerated). 4-6 weeks once reconstituted.

Storage Temperature

2-8°C (refrigerated)

Shelf Life

4-6 weeks once reconstituted

Important Notes

  • Use bacteriostatic water for multi-dose vials
  • Inject water slowly down the side of the vial
  • Allow to dissolve naturally without shaking
  • Store away from light to prevent degradation
  • Lyophilized powder stable at room temperature for short periods

Safety & Side Effects

Reported Side Effects

  • !Mild injection site irritation or redness
  • !Temporary swelling at injection site
  • !Rare allergic reactions or hypersensitivity
  • !Potential headaches in sensitive individuals
  • !Minor bruising at injection sites
  • !Transient fatigue following initial doses
  • !Possible changes in sleep patterns
  • !Rare reports of nausea or digestive upset
  • !Potential interaction with wound healing in diabetic subjects

Potential Interactions

  • May enhance effects of other healing peptides like BPC-157
  • Potential interactions with anticoagulant medications
  • Could affect the efficacy of certain chemotherapy drugs
  • May interact with immunosuppressive medications
  • Possible enhancement of growth hormone effects

Important: Side effects and interactions listed here are compiled from published research and community reports. This is not a complete list. No formal drug interaction studies have been conducted for most research peptides. Always consult a qualified healthcare provider.

Research Studies

The following studies are referenced in this profile. PubMed IDs are provided where available for independent verification.

Ac-SDKP inhibits transforming growth factor-β1-induced differentiation of human lung fibroblasts into myofibroblasts

Peng H, et al.2010American Journal of Physiology
PMID: 20833775

Study demonstrated that Ac-SDKP prevents lung fibroblast differentiation, suggesting anti-fibrotic properties that could benefit tissue healing.

The tetrapeptide AcSDKP, an inhibitor of primitive hematopoietic cell proliferation, induces angiogenesis in vitro and in vivo

Cavasin MA, et al.2004Blood
PMID: 15142872

Research showed that Ac-SDKP promotes blood vessel formation both in laboratory and animal models, supporting its angiogenic properties.

Ac-SDKP reverses inflammation and fibrosis in rats with heart failure after myocardial infarction

Peng H, et al.2014Hypertension
PMID: 25421976

Study found that Ac-SDKP treatment reduced cardiac inflammation and scarring following heart attack in animal models.

Anti-inflammatory effects of the hemoregulatory peptide N-acetyl-seryl-aspartyl-lysyl-proline

Castilla A, et al.1991Journal of Clinical Investigation

Early research establishing the anti-inflammatory properties of the tetrapeptide and its mechanisms of action.

Note: This is not an exhaustive list of all published research. Studies are selected for relevance and quality. Click PubMed IDs to verify sources independently. Inclusion does not imply endorsement of the peptide for any clinical use.

Frequently Asked Questions

TB4-Fragment is a shorter, four amino acid sequence (Ac-SDKP) derived from the full Thymosin Beta-4 protein. The fragment is more stable, has better bioavailability, and shows more targeted effects while retaining many healing properties of the parent compound.

Research suggests initial effects on inflammation may be observed within 3-7 days, while tissue healing and regenerative effects typically become apparent after 2-4 weeks of consistent administration.

Research indicates TB4-Fragment may work synergistically with other healing compounds like BPC-157, but combination protocols should be carefully designed with appropriate spacing and monitoring.

TB4-Fragment offers advantages in stability and targeted action, with potentially fewer side effects than the full protein. However, the choice depends on specific research goals and the particular biological pathways being studied.

Subcutaneous injection in the abdomen or thigh is most common for systemic effects. For localized healing research, direct injection near the target tissue may be preferred, though this requires more precise administration.

Once reconstituted, store in the refrigerator at 2-8°C and use within 4-6 weeks. Keep away from light and avoid freezing the solution. Lyophilized powder can be stored at room temperature briefly but refrigeration extends shelf life.

Most research protocols involve 4-8 week cycles with 2-4 week breaks to prevent desensitization and allow assessment of sustained effects. Continuous use beyond 8 weeks should be carefully monitored.

The most frequent side effects are mild injection site reactions including redness, swelling, or irritation. Systemic effects are rare but may include temporary fatigue or headaches in sensitive individuals.

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Research & Educational Use Only

All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.

The information presented here is compiled from published research studies and is intended for informational purposes only. Individual results may vary. Always consult with a licensed healthcare provider.