Thymosin Beta-4 Sulfoxide (TB4-SO)
Also known as: Thymosin Beta-4 Sulfoxide, TB4-S, Oxidized TB4
Overview
Thymosin beta-4 sulfoxide (TB4-SO) is the naturally occurring oxidized form of Thymosin Beta-4 generated by methionine-6 oxidation. Unlike the reduced parent compound, TB4-SO does not bind G-actin and thus lacks TB-500's actin-sequestering activity. Instead, TB4-SO has potent and specific anti-inflammatory properties independent of G-actin binding—activating the Nrf2 transcription factor pathway to upregulate antioxidant and anti-inflammatory gene expression. TB4-SO is considered an important endogenous immunomodulatory signal in inflammatory conditions where ROS-mediated oxidation of TB4 occurs.
Mechanism of Action
TB4-SO specifically interacts with Kelch-like ECH-associated protein 1 (KEAP1), the E3 ubiquitin ligase that normally targets Nrf2 for proteasomal degradation. By binding KEAP1, TB4-SO displaces Nrf2 from the KEAP1-Nrf2 complex, allowing Nrf2 to translocate to the nucleus and activate antioxidant response elements (AREs). This drives expression of heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase-1 (NQO1), glutamate-cysteine ligase, and other cytoprotective enzymes. This mechanism is mechanistically distinct from TB4's G-actin binding and operates independently at sites of oxidative stress.
Potential Benefits
- Anti-inflammatory activity via Nrf2 pathway activation
- HO-1 upregulation with potent cytoprotective effects
- Antioxidant gene expression induction
- Endogenous anti-inflammatory signal generated under oxidative stress
- Potential in inflammatory bowel disease and oxidative stress conditions
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | Research-only peptide |
| Intermediate | N/A |
| Advanced | N/A |
| Cycle Duration | 4-12 weeks (research) |
Oxidized sulfoxide form of TB4 — proposed as the 'active' anti-inflammatory metabolite. Limited standalone human data.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous Injection High
Parallel to TB-500 administration.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Thymosin Beta-4 Sulfoxide (TB4-SO):
Extended Healing Stack
Research extension of the classic healing stack emphasizing the oxidized TB4 metabolite.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Storage | Refrigerate at 2-8°C after reconstitution. Do not freeze reconstituted solution. |
|---|
Typical vial sizes: 2-5 mg. Add bac water slowly down the side of the vial, swirl gently — do not shake. Use insulin syringe for precise dosing.
Need exact syringe measurements?
Amino Acid Sequence
Ac-Ser-Asp-Lys-Pro-Asp-Met(O)-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser (Met6 → Met6-sulfoxide)
Side Effects & Safety
- Not independently characterized; see TB-500 entry
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
Pharmacokinetics
| Half-Life | Similar to TB-500 parent — ~2-3 hours plasma |
|---|---|
| Storage | Store lyophilized peptide at -20°C (long-term) or 2-8°C (short-term, under 30 days). Reconstituted: refrigerate at 2-8°C and use within 28-30 days. Protect from light. Do not freeze reconstituted solution. |
Synergistic Compounds
The following compounds have been studied alongside Thymosin Beta-4 Sulfoxide (TB4-SO) for potential complementary or synergistic effects:
Learn More
References & Further Reading
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