Quick summary
Thymosin Beta-4 Sulfoxide is the oxidized form of TB-4 with potent extracellular anti-inflammatory properties. It inhibits neutrophil chemotaxis and shows efficacy in cardiac injury models.
Overview
Thymosin Beta-4 Sulfoxide (Tβ4-SO) is the oxidized form of thymosin beta-4, generated by the addition of an oxygen atom to the methionine-6 residue. Unlike the native peptide which sequesters G-actin intracellularly, Tβ4-SO is a potent extracellular anti-inflammatory signaling molecule generated by monocytes in the presence of glucocorticoids. It represents a biologically distinct entity with properties complementary to but different from parent TB-4.
Mechanism of action
Oxidation of Met-6 attenuates Tβ4's G-actin-sequestering activity while greatly enhancing its extracellular signaling properties. Tβ4-SO inhibits neutrophil chemotaxis and is thought to be the secreted, extracellular signaling form of the parent peptide. In vivo, Tβ4-SO — but not the native form — potently inhibits carrageenan-induced paw edema in mice. In cardiac models, Tβ4-SO attenuates inflammatory cell infiltration and promotes wound healing post-infarction. It may represent part of the mechanism by which glucocorticoids exert anti-inflammatory effects via monocyte-secreted peptides.
Dosing protocols
| Purpose | Route | Dosage | Frequency | Notes |
|---|---|---|---|---|
| anti-inflammatory research (animal) | subcutaneous | 1–5 mg/kg | per study protocol |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
Research summary
Key research by Bhatt et al. (1999, Nature Medicine) established Tβ4-SO as an anti-inflammatory monocyte product in the presence of glucocorticoids. A 2013 Nature Communications study demonstrated that Tβ4-SO reduces inflammatory infiltrate and promotes healing in murine cardiac injury models. At sites of inflammation, the respiratory burst oxidizes extracellular Tβ4 to the sulfoxide in vivo, suggesting Tβ4-SO is the physiologically active extracellular form.[1][2][3][4]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with Thymosin Beta-4 Sulfoxide for synergistic effects.
Legal status
Thymosin Beta-4 Sulfoxide is a research chemical. Not FDA-approved. One of 14 peptides under FDA reclassification review (parent TB-4 / TB-500). Available from specialty research peptide suppliers.
Sourcing & access
Research compound
Thymosin Beta-4 Sulfoxide is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).
Frequently asked questions
Thymosin Beta-4 Sulfoxide is the oxidized form of thymosin beta-4, created by the addition of an oxygen atom to the methionine-6 residue. Unlike native TB-4 which sequesters G-actin intracellularly, the sulfoxide form is a potent extracellular anti-inflammatory signaling molecule.
Oxidation of Met-6 attenuates G-actin-sequestering activity while greatly enhancing extracellular signaling. Tb4-SO inhibits neutrophil chemotaxis and inflammatory cell infiltration. It is secreted by monocytes in the presence of glucocorticoids and may represent part of how glucocorticoids exert anti-inflammatory effects.
Thymosin Beta-4 Sulfoxide is a research-only compound with limited human safety data — no clinical trials have been conducted in humans. Reported adverse reactions in research settings include injection-site reactions and transient fatigue described anecdotally. It is not FDA-approved, and although parent TB-4 is among the 14 peptides under FDA reclassification review, the sulfoxide form has no regulated clinical pathway.
While TB-500 (native TB-4) primarily works intracellularly by sequestering G-actin and promoting tissue repair, the sulfoxide form is the extracellular signaling variant with potent anti-inflammatory properties. In cardiac models, Tb4-SO reduces inflammatory infiltrate and promotes healing post-infarction.
Research references
- Thymosin beta-4 sulfoxide is an anti-inflammatory mediator in macrophagesPubMed
- Oxidized thymosin beta-4 reduces inflammation and promotes wound healingPubMed
- Thymosin beta-4 isoforms and their differential effects on actin dynamicsPubMed
- Thymosin beta-4 in cardiac repair and anti-apoptotic protectionPubMed