Thymosin beta-4 (full length)

This entry exists so that the real human trial record of full-length thymosin beta-4 is neither lost nor credited to TB-500, the 7-residue fragment sold under its name. The two are different molecules and FDA says so explicitly. Full-length thymosin beta-4 is not approved by any regulator for any indication either.

It did go through registered, placebo-controlled human trials, and the honest summary is that they were safe and they failed on efficacy. Two Phase 2 trials of topical gel, 72 patients each, in pressure ulcers and venous stasis ulcers found no statistically significant difference from placebo in complete wound healing at any of three concentrations; in the venous study the low and high concentrations performed worse than placebo and there was no dose-response. A 700-participant randomised trial of the ophthalmic form in dry eye disease, ARISE-3, reported statistically significant improvements in pre-specified secondary endpoints and in a post-hoc subpopulation analysis — but the announcement does not name the primary endpoint or say whether it was met, and gives no group values or effect sizes. The ophthalmic product remains unapproved.

The entire human record consists of company announcements rather than peer-reviewed papers, and every trial was run by the developer or its largest stockholder. Two further registrations, NCT00382174 in pressure ulcers and NCT00832091 in venous stasis ulcers, correspond to the two Phase 2 trials; no additional results were extracted from them. WADA prohibits thymosin beta-4 and its derivatives at all times.