Also known as: Tβ4
A naturally occurring 43-amino-acid peptide and the most abundant member of the beta-thymosin family in human cells. Research is mostly animal and cell work, with a small number of early human trials described in reviews.
Thymosin beta-4 is established as a G-actin-binding peptide that helps regulate the cell's actin cytoskeleton [1]. Reviews describe proposed downstream effects on cell migration, blood-vessel formation and inflammation, linked in animal work to PI3K/Akt, Notch and TGF-beta/Smad signaling [1]. In mouse lung and heart models, researchers proposed that it acts through mitophagy and reduced inflammasome activation [2][3]. A mouse genetic study found that the body's own thymosin beta-4 in liver stellate cells was linked to Hedgehog signaling and scar-tissue formation [4].
| Study | Model | Reported result | Source |
|---|---|---|---|
| LPS lung model [2] | Mouse LPS lung model in mice given AAV-delivered thymosin beta-4; human lung epithelial cells and fibroblasts | Researchers reported lower oxidative-stress, inflammation and fibrosis markers; reduced TGF-beta1-driven fibroblast activation in cells | Peer-reviewed Inflammation 2022 |
| Coronary-ligation heart model [3] | Mouse Coronary-artery-ligation model in mice given AAV-delivered thymosin beta-4; mouse heart muscle cells and myofibroblasts | Researchers measured lower oxidative damage, inflammation and fibrosis markers, and better cardiac function measures vs untreated model | Peer-reviewed Cardiovasc Ther 2022 |
| Stellate-cell deletion study [4] | Mouse Transgenic mice lacking thymosin beta-4 in activated liver stellate cells; CCl4 and bile-duct-ligation fibrosis models | Deleting the peptide lowered liver fibrosis markers via reduced Hedgehog signaling; restoring it by AAV brought fibrosis back | Peer-reviewed Cells 2023 |
| Scoping review of tissue studies [5] | Review 80 studies (cell, animal, human, registered trials) of thymosin beta-4 and TB-500, searched to March 2026 | Evidence mostly preclinical; most studies on wound/skin, vascular, eye and bone tissue; direct TB-500 evidence limited to one study | Peer-reviewed Appl Sci 2026 |
| Narrative review of function [1] | Review Summary of animal studies in mice, rats, rabbits and pigs plus early human trials | Summarizes rodent fibrosis, eye, skin and hair-growth findings and phase 1 safety studies in healthy volunteers | Peer-reviewed Front Endocrinol 2021 |
Human trials are listed for research context only; outcomes are reported in the linked publications. Animal and lab results do not establish effects in humans.
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