TB-500 legal status: which decision was actually made?

Is TB-500 FDA approved for human use?

No. TB-500 has no FDA approval for human use and no approved therapeutic indication. The official FDA safety-risk page describes the thymosin beta-4 fragment, LKKTETQ, also known as TB-500.

Its nomination now sits in the FDA's withdrawn table, outside Category 2. FDA's safety concerns are retained. FDA does not publish a date on which it moved the peptide out of Category 2. The table records a withdrawn nomination; it records neither Category 1 placement nor drug approval.

The safety concerns include missing human safety information and potential immune reactions. Treating disappearance from a category as approval asks me to read a surviving safety warning as a favorable clinical judgment. The withdrawal also establishes no new permission to compound TB-500.

Drugs@FDA and the compounding record answer different questions

The question behind a Drugs@FDA TB-500 search is whether there is an official FDA-approved human use. There is no approved TB-500 indication. A compounding nomination cannot supply one.

FDA’s Section 503A framework concerns patient-specific compounded preparations and the bulk substances that may be used in them. A valid prescription is one requirement; an eligible bulk ingredient is another. Eligibility can depend on an applicable drug monograph, use in an approved drug, or inclusion on the relevant FDA list. The law does not make every nominated ingredient available for compounding.

Section 503B concerns FDA-registered outsourcing facilities and has its own requirements. Calling a preparation compounded is not a drug-approval claim. These distinctions do more for me than an all-purpose legal-or-illegal label: they identify the particular decision that is still needed.

The July 2026 meeting notice

The FDA advisory-committee notice for July 23–24, 2026 listed two lab forms of TB-500 for consideration for the 503A Bulks List. It also listed other substances. The scheduled meeting date has passed; the sources available here do not record its outcome or a final FDA listing decision.

The January 7, 2025 revised interim policy stopped placing newly nominated substances into numbered categories. Existing Category 2 substances retained the associated limits. TB-500's nomination appears in a separate withdrawn table. Neither that table nor a meeting agenda grants new compounding permission.

The announcement records the planned meeting; the agency's decision still needs its own record. A proposal, a committee discussion and an agency decision are different stages. The dated records here support only the stages they actually document.

A prescriber decides; the pharmacy still has its own question

A licensed U.S. clinician's assessment can lead to a TB-500 prescription, or the clinician can refuse the request. A clinical relationship and a valid prescription do not replace the separate requirements governing the pharmacy and its bulk ingredient. Availability also depends on the state and treatment.

This is why a prescribing statement cannot be read as FDA approval or universal eligibility. A request still awaits a prescribing decision, and each compounded preparation requires authority beyond the prescription alone. The withdrawn nomination leaves those distinctions in place.

This page records general regulatory facts from the dated source set. It is not legal advice for an individual case, and it cannot establish an agency outcome that the source set does not contain.

The sports ban does not wait for a clinical verdict

TB-500 and thymosin beta-4 are prohibited by WADA in and out of competition under its peptide, growth-factor and tissue-repair categories. The sports-medicine review discusses the prohibited status of these unapproved peptides, while the equine doping-control study shows why analytical detection is a substantial part of the TB-500 record.

I do not take the ban as evidence that TB-500 improves performance. A sports rule and a clinical efficacy result answer different questions. The prohibited status is settled here; a recovery benefit remains unproven.