This article is educational and does not replace medical advice. Prescription medication requires review by a licensed clinician and, when appropriate, a valid prescription. Compounded medications are not FDA-approved, and the FDA does not verify their safety, effectiveness or quality before marketing. Treatment eligibility is an individual clinical decision.

Released: July 12, 2026·Last reviewed: October 15, 2026·Methodology v4.1

Researched By

Medical Researcher · Western University of Health Sciences

Medically Reviewed By

Dr. Jonathan Snipes, MD · Kim Callender, NP (FNP-BC)

Last medically reviewed: October 15, 2026 · This page is informational and does not constitute medical advice.

This page is maintained. Prices are re-read at source and dated; evidence is checked against the published trial. Newest across the site: news · research · corrections.

TB-500 (thymosin beta-4 fragment): evidence, legality and safety

Quick answer

FDA status, read October 15, 2026TB-500 (thymosin beta-4 fragment): Withdrawn from Category 2; not Category 1; not on the 503A list. Listed under “nominated but withdrawn” on FDA’s Category 2 page. FDA’s briefing cited “the non-existing information on the use of these substances administered in humans” and proposed not adding it for wound healing; the committee reportedly voted 8–6 with one abstention to recommend it. What the July vote did and did not change → Sources: FDA Category 2 page · 503A category lists (May 14, 2026).

TB-500 is a synthetic version of a thymosin beta-4 fragment marketed for recovery and healing. It is NOT FDA-approved, and human clinical evidence is minimal. It is widely sold as a 'research chemical,' which is not a lawful pathway for human use.

Regulatory statusNot FDA-approved. Human evidence minimal.

What does the evidence actually show?

What human clinical evidence exists?

No adequate, well-controlled human trials establish efficacy or safety for the marketed uses.

What do the animal and laboratory studies show?

Some preclinical work on tissue repair and angiogenesis exists; it does not establish human benefit. We keep animal and laboratory findings clearly separated from human evidence, because preclinical results routinely fail to translate to people.

What are the known and potential risks?

Unapproved status, unregulated sourcing, and unknown long-term safety.

No consumer dosing for research compoundsThis page does not provide dosing instructions for unapproved compounds, and we do not link to research-chemical sellers. If you are considering peptide therapy, do it through a licensed clinician who can weigh your individual risks.

Is it legal, and where does it come from?

The lawful pathway for any prescription peptide is a licensed clinician and a licensed pharmacy. Products labeled "for research use only" are not lawfully sold for human consumption. See how to verify a peptide provider and research peptides versus prescription therapy.

Is it banned in sport?

Assume prohibited; verify against the current WADA Prohibited List.

Frequently asked questions

Is TB-500 (thymosin beta-4 fragment) FDA-approved?

Not FDA-approved. Human evidence minimal.

Is there human evidence for TB-500 (thymosin beta-4 fragment)?

No adequate, well-controlled human trials establish efficacy or safety for the marketed uses.

Is TB-500 (thymosin beta-4 fragment) legal to buy?

Many peptides in this category are sold as 'research chemicals,' which is not a lawful pathway for human use. Legitimacy depends on approval status and whether a licensed clinician and pharmacy are involved. We do not link to research-chemical sellers.

Is TB-500 (thymosin beta-4 fragment) banned in sport?

Assume prohibited; verify against the current WADA Prohibited List.

Sources

U.S. Food and Drug Administration — enforcement actions and warnings on unapproved peptide products.
World Anti-Doping Agency (WADA) Prohibited List — current edition.
Peer-reviewed preclinical and (where available) clinical literature, graded for evidence quality.

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How the dates on this page work. Manufacturer self-pay prices were re-read on 15 October 2026: NovoCare’s Wegovy page and Lilly’s Zepbound savings page. Foundayo prices are carried from LillyDirect pages archived 25 September 2026, because lilly.com blocked automated reads. Figures captured from telehealth provider websites carry the date we read that provider’s page, which may be earlier; where it is, the row or a dated notice says so. We do not restamp a figure we have not re-read.