Studies of the whole protein do not show whether TB-500 works.

TB-500 had no published human study in the FDA review checked September 30, 2026. Human research on full-length thymosin beta-4 is research on a different substance.

The eye-drop results were mixed

A study reported in 2015 gave full-length thymosin beta-4 eye drops or comparison drops to seventy-two people with dry eye. The main questions were whether the drops eased eye discomfort and improved a dye test for damage on the eye’s surface. Neither result showed a clear difference between the groups. Some other measures improved, but the study still missed its main goals. The source summary used here does not name those other measures.

A later eye-drop study of the whole protein had seven hundred participants. Its main results for eye discomfort and the eye-surface dye test were much alike with treatment and comparison drops.

Comparison drops act as a stand-in so researchers can compare groups. A change in a smaller measure does not erase a missed main goal. Keep both parts of the result in view.

The skin-gel studies were small

For leg sores and pressure sores, small studies applied a gel containing full-length thymosin beta-4. Similar shares of wounds closed with the treatment gel and its comparison gel. The records did not post a statistical comparison, which checks whether a group difference could reflect chance. That leaves the question of benefit open.

A short safety study has a narrow reach

An early study gave full-length thymosin beta-4 into a vein in healthy volunteers. The reported side effects were infrequent and mild or moderate, with none reported as serious.

Those findings concern the full protein and the conditions of that study. They cannot establish TB-500’s safety.