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Clinician reference, evidence review

TB-500

Thymosin Beta-4 fragment

Regenerative peptide, research grade, not FDA approved

Reviewed by: Sabrina Runbeck, PA-C, MHS, MPH, Co-Founder, Scriptura Health. Physician assistant, public health master's, health sciences master's. Sabrina reviews the clinical layer of Scriptura Health, and she reviews every compound reference on this site.

Published: 2026-07-08. This page is an evidence review, not clinical instruction, and does not recommend dosing, cadence, routes, or prescribing decisions. Prescribing is the responsibility of a licensed clinician evaluating a specific patient.

Regulatory posture

TB-500 is a synthetic fragment marketed as related to thymosin beta-4, and neither TB-500 nor thymosin beta-4 is FDA approved for any human indication. The compound is not established for lawful 503A or 503B compounding and has been flagged among peptides lacking adequate safety characterization. It is not scheduled by the DEA, but thymosin beta-4 is prohibited in sport by the World Anti-Doping Agency.

Mechanism, plain English

Thymosin beta-4 is a small protein made naturally in the body that helps control actin, a protein that gives cells their shape and lets them move. Because it helps cells migrate and organize, researchers have studied it for wound repair, blood vessel growth, and reducing inflammation. TB-500 is a synthetic version studied mainly in animals, so its exact behavior in humans is not well defined.

Evidence landscape

The evidence base for thymosin beta-4 is largely preclinical, with a smaller number of early human studies. A widely cited review describes its many regenerative properties and outlines potential clinical applications, but frames most findings as experimental rather than proven. Early clinical work in ophthalmology has moved thymosin beta-4 from bench to bedside for dry eye and corneal healing, but these programs are limited in size and not broadly established. A 2023 review discusses regenerative and anti-aging directions while noting the science is still developing and lacks large confirmatory trials. Overall the literature reports biological plausibility and some early clinical signals, but does not support broad efficacy or safety conclusions for the injectable products marketed as TB-500.

Primary PubMed citations

  1. Thymosin beta4: a multi-functional regenerative peptide. Basic properties and clinical applications , Goldstein AL et al, Expert Opinion on Biological Therapy, 2012. PMID: 22074294
  2. Thymosin beta 4 and the eye: the journey from bench to bedside , Sosne G et al, Expert Opinion on Biological Therapy, 2018. PMID: 30063853
  3. Thymosin beta-4 denotes new directions towards developing prosperous anti-aging regenerative therapies , Bock-Marquette I et al, International Immunopharmacology, 2023. PMID: 36709593

Citations selected from the PubMed literature. Every URL was checked at publication time. Scriptura's daily PubMed scan surfaces new studies for each compound as they index. See the regulatory and literature layers on the demo.

Scope of this page

This is a plain English summary of the peer reviewed literature and current regulatory posture. It is not a substitute for a licensed clinician's judgment on a specific patient. It does not recommend dosing, cadence, or route. Where the literature is limited or preclinical, this page says so, so a prescriber can weigh marketing claims against what the trials actually show.

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TB-500 clinician reference: evidence review and regulatory posture | Scriptura Health | Scriptura Health