TB-4.
An endogenous 43-amino-acid peptide found at high concentrations in virtually all human cells. Thymosin Beta-4 is the body's primary actin-sequestering protein — controlling the cytoskeleton dynamics that drive wound healing, cardiac repair, and tissue regeneration.
Want the full narrative? Read the TB-4 Research Guide for the published-study discussion and mechanism deep-dive.
- Key Signals
- Wound · Cardiac · Repair
- Origin
- Endogenous (all human cells)
- Investigator
- Low et al., 1981
- Class
- Actin-sequestering peptide (43 AA)
- Status (UAE)
- Research compound (off-label)
The Repair Peptide Hidden in Plain Sight
Low et al. isolate Thymosin Beta-4 from bovine thymus in 1981; later found at high levels in platelets and wound fluid.
Identified as the primary G-actin sequesterer in human cells — controlling cytoskeletal dynamics critical for wound closure.
RxBio advances TB-4 into Phase I/II trials for wound healing and dry eye syndrome — the first actin peptide in human trials.
The body's own repair blueprint
Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys
Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Glu-Thr-Gly
Gln-Glu-Lys-His-Ser-Glu-Gly-Ala-Ile-Ile-Lys
Lys-Val-Ile-Glu-Glu-Glu-Leu-Lys-Pro-Leu
C₂₁₂H₃₅₀N₅₆O₇₈S · MW 4964 Da
A 43-residue peptide present at high concentrations in platelets, white blood cells, and wound fluid — binding G-actin with high affinity and acting as master regulator of actin dynamics across human cell types.
Already in you — now studied.
Preclinical signal is unusually robust; human trial data exists but remains limited in scale.
- Wound closure (excisional)
- Cardiac repair (post-MI)
- Corneal wound healing
- Hair follicle activation
- Anti-inflammatory signal
- Wound healing (Phase II)
- Dry eye syndrome (Ph.II)
- Safety confirmed (Ph.I)
- No approved indication
- Neurological regeneration
- Systemic anti-aging use
- Muscle growth claims
- Spinal cord repair
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Mechanism deep-dive and research dosing protocols — available to registered researchers. It's free and takes under a minute.
TB-4's Closest Approach to Approval
In the UAE, research-grade peptides occupy a defined regulatory category distinct from licensed medicines. Compounds sold under this classification — including those offered by Dubai Peptides — are intended exclusively for qualified research applications, not for human administration.
TB-4 is unique among research peptides in having completed Phase I safety trials and a Phase II study for neurotrophic dry eye syndrome — the most advanced actin-binding peptide to reach human trials. No new drug application has been filed despite positive safety data; commercial development stalled after the Phase II endpoint. Being endogenous, TB-4 is present in every human cell — a rare distinction.
Low et al. isolate Thymosin Beta-4 from bovine thymus; found in all human cells at high levels.
RxBio initiates Phase I/II wound-healing and dry eye studies — first actin peptide in trials.
An off-label compounding market for TB-4 exists in the UAE, operating outside the research-use classification this platform follows.