Pepvise
Explainer· Compounds

TB-500 dosage, what the literature shows

By The PepVise Editorial Team · Reviewed August 4, 2026 · 10 min read

Why there is no established human dose for TB-500, how it differs from the pharmaceutical Thymosin beta-4 that was actually trialed, and why unverified research-chemical purity makes the milligram figures shared online meaningless. PepVise prescribes nothing.

Mechanism explainers on PepVise aim for textbook-level clarity without the textbook's refusal to commit to a reading.
Frequently asked

What readers ask us next.

What dose of TB-500 is established in humans?
None. There is no dose established in controlled trials, no approved dose, and no prescribing-label dose for the material sold as TB-500. The human trials that exist were run on pharmaceutical full-length Thymosin beta-4, not on the research-chemical fragment. Any figure quoted for TB-500 is a convention from animal studies and forum practice, not an established protocol.
Is TB-500 the same as Thymosin beta-4?
Not as sold. Thymosin beta-4 is the full-length 43-amino-acid protein that was carried into human trials as pharmaceutical products such as RGN-259 and RGN-352. TB-500 in the research-chemical channel is usually marketed as a shorter synthetic fragment of that molecule with unverified identity, which is why a dose from a Thymosin beta-4 trial cannot simply be applied to it.
Where do the milligram figures online come from?
They are drawn from preclinical rodent and equine studies and from user convention, then scaled to a human body weight by allometric conversion. That conversion is a crude estimate, not a procedure validated for this peptide, and the loading-and-maintenance schedules repeated in forums have no basis in human dose-finding research.
Why does PepVise not give a specific TB-500 dose?
Because no human dose is established, because the material sold as TB-500 has unverified identity and purity, and because we do not recommend administering an unapproved research peptide. A number from a website is no substitute for assessment by a licensed clinician within a regulated pathway. We describe what the literature reports and leave any use decision to medicine.
Is TB-500 banned in sport?
Yes. Thymosin beta-4 and its fragments appear on the World Anti-Doping Agency prohibited list, so any athlete subject to anti-doping rules should treat TB-500 as prohibited in and out of competition. That status is independent of the dosing question and applies regardless of the amount used.
The sources

References cited on this page.

PubMed, ClinicalTrials.gov, and FDA documents only. Secondary sources appear when needed to characterize public discourse, never as a source for a clinical claim.

  1. [01]Bock-Marquette I et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature 2004 (preclinical pharmacology of the parent molecule)
  2. [02]Crockford D et al. Thymosin beta4: structure, function, and biological properties supporting current and future clinical applications. Ann N Y Acad Sci 2010 (review of the trialed pharmaceutical forms)
  3. [03]ClinicalTrials.gov, 'thymosin beta 4' listings (RGN-259 corneal, RGN-352 cardiac programs)
  4. [04]WADA Prohibited List, 2026 edition, S2 peptide hormones and growth factors
The masthead

About The Pepvise Editorial Team

The Pepvise Editorial Team is a small group of researchers and science writers reading the peer-reviewed peptide literature and translating it into calm, cited analysis. We do not sell peptides, recommend peptides, or tell readers what to administer. We describe what has been measured, by whom, at what scale, with what effect size.

Compound reviews are signed off by Dr. Priya Narang, MD, MPH (endocrinologist) and Dr. Marcus Haley, PharmD, BCPS (board-certified clinical pharmacist). Both hold verifiable state-board licenses and have signed editorial-independence letters with us. See the full editorial board →

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