TB-500: FDA, Compounding & WADA Status

FDA approval status

TB-500 is not an FDA-approved drug. It is not a component of an approved medicine. A UNII, QHK6Z47GTG, records identity. The record does not authorize a clinical use.^1,6

This page does not claim that FDA approved, legalized, or placed TB-500 on the final 503A Bulks List. As of the evidence-review date, 1 September 2026, we do not cite a final rule adding it.

503A evaluation

On July 23, 2026, the Pharmacy Compounding Advisory Committee discussed TB-500 free base and TB-500 acetate as bulk substances being considered for the 503A Bulks List. The use FDA evaluated was wound healing.^2,1

The original nomination was inconsistent about whether the free base or the acetate was proposed, and it was later withdrawn. FDA evaluated both forms on its own initiative. The briefing introduction reminds readers that the package is meant to obtain advice and that the Agency does not issue a final determination until that process has been considered.^1,3

FDA staff recommendation

Staff concluded that the evaluation criteria weighed against placing TB-500 free base and TB-500 acetate on the 503A Bulks List. Reasons included chemical-characterization concerns, inconsistent naming, absence of human clinical evidence, limited safety information, immunogenicity and aggregation, and lack of direct effectiveness evidence.¹

That is the staff evaluation for the committee. It is not, by itself, a rule. It is also not approval in disguise.

PCAC advisory vote

Professional reporting describes a committee vote in favor of recommending inclusion of TB-500-related substances, commonly given as 8 yes, 6 no, and 1 abstention. The source of that tally is trade and professional reporting, not official minutes reproduced here.⁴

The count is not the main point. The PCAC vote is advisory. It did not approve TB-500 as a drug. It did not establish wound-healing efficacy. It did not place TB-500 automatically on the final 503A list. It did not create authorization in Mexico.^3,4

Safety-data gap

FDA did not identify human exposure data using TB-500. It also did not identify, at the time of that evaluation, a nonclinical toxicology body that would support the proposed use. The absence of those data is part of the record, not a space filled by forum anecdotes.¹

Immunogenicity and aggregation

Within FDA’s scope, the immunogenicity concern is tied to an injectable product: impurities, peptide aggregates, and insufficient analytical controls on the certificates reviewed. This page does not generalize that concern to every route or turn it into a diagnosis. It stays inside the injectable compounding record the Agency evaluated.¹

WADA 2026

The 2026 WADA Prohibited List includes thymosin-β4 and TB-500 under section S2.3, growth factors and growth factor modulators. The fact is classification. The source is the official list. The date of that list is 2026.⁵

This page does not describe detection windows, when to stop a material before competition, how testing laboratories operate, or ways to mask or evade a test. Those details do not belong on a status page.

United States versus Mexico

A 503A evaluation, an advisory vote, and a WADA listing are facts from other systems. They are not extrapolated to COFEPRIS. Mexico does not inherit a U.S. compounding list or an anti-doping decision as if they were a local sanitary registration.

Research materials on this site remain laboratory materials. Nothing on this page authorizes a clinical, veterinary, or sporting use.

FDA also noted that TB-500 has no USP or NF monograph, is not a component of an approved drug, and that it found no authorized products in several European countries, Canada, Australia, or from the EMA. Those findings describe an absence of approval. They do not describe a gap that an advisory vote can fill by itself.¹

Four layers have to stay separate. First: the staff evaluation, against inclusion. Second: the committee’s advisory vote, reported by trade press. Third: possible FDA rulemaking, which as of this date we do not cite as a final rule. Fourth: drug approval, which has not occurred. Collapsing any of those layers into the next one is the regulatory error this page exists to stop.^1,4,3

• What human evidence FDA found — and did not find
• The TB-500 definition the Agency uses
• TB-500 research hub