TB-500 Dosage: What Community Protocols Report
Last updated May 19, 2026 · Reviewed by Grey Peptides Editorial Board · ✓ Primary-sourced
← TB-500 encyclopedia entry · See also: BPC-157 dosage · BPC-157 + TB-500 stack
TB-500 is investigational and not FDA approved, and no human clinical trial has defined a TB-500-specific dose. The numbers below are self-reported community protocols — not a validated regimen and not a recommendation. They are documented here so readers can recognize and critically evaluate what they encounter. Self-administering an unapproved compound of uncertain identity, purity, and sterility carries unknown and potentially serious risks.
The short version
TB-500 is a short synthetic peptide corresponding to the actin-binding region (the sequence LKKTETQ) of thymosin β4, a naturally occurring 44–amino-acid regenerative peptide. It is used in community protocols for soft-tissue injury, often stacked with BPC-157, on the basis of preclinical work on cell migration, angiogenesis, and tissue repair. Because it has never been through a human efficacy trial, there is no titration schedule, no approved maximum, and no maintenance dose in any official sense — only conventions that have propagated through forums.
This is the single most important point for reading TB-500 dosing. Full-length thymosin β4 has been studied in FDA-registered trials — for example RGN-259/Lacripep for dry eye, and earlier work in cardiac repair. TB-500 as marketed is the short fragment, not full thymosin β4. The two are not interchangeable, so the doses, safety findings, and outcomes from those trials cannot be borrowed to justify a TB-500 protocol.
What community protocols report
The most commonly cited pattern is a two-phase approach. Again, these are descriptive, not prescriptive.
| Phase | Reported amount | Frequency | Typical span | Route |
|---|---|---|---|---|
| Loading | 2–2.5 mg | 1–2× weekly | ~4–6 weeks | SubQ |
| Maintenance | 2–2.5 mg | ~1× weekly or biweekly | ongoing in protocol | SubQ |
The once-weekly cadence reflects a belief that the fragment persists in tissue longer than its plasma presence suggests — but TB-500 fragment pharmacokinetics are not well characterized in published human data. Full thymosin β4 has a short plasma half-life on the order of an hour; what that implies for the fragment dosed weekly is unknown. In short, the schedule rests on assumption rather than measured human data.
Reconstitution basics
TB-500 is supplied as a lyophilized powder that must be reconstituted with bacteriostatic water before any dose can be measured. Because the amounts are in milligrams but vials and syringes are small, an error in the dilution math translates directly into a wrong dose. If you are working through the arithmetic conceptually:
→ Reconstitution Calculator — turns vial strength + BAC water volume into an exact syringe draw, with a visual syringe.
→ Half-Life Visualizer — explore how dosing cadence shapes drug levels (note: TB-500 fragment half-life in humans is undetermined, so any model is illustrative).
A calculator handles the math but cannot verify that what is in the vial is actually TB-500, is pure, or is sterile. Those remain unknowns outside a regulated supply chain.
Where TB-500 stands legally
The FDA placed TB-500 on its 503A Category 2 list (significant safety concerns, not compoundable) in 2023. On April 15, 2026, after nominations were withdrawn, it was among twelve peptides removed from Category 2 — which does not make it approved or move it to Category 1. TB-500 is scheduled for PCAC review on July 23, 2026. Until that concludes, it remains outside the approved-medicine framework. Our Regulatory Status Tracker follows the timeline as it develops.
Frequently asked questions
Why is TB-500 dosed weekly when full Tβ4 clears in about an hour?
Community protocols assume a prolonged tissue effect that justifies infrequent dosing, but this is not established for the fragment in humans. The honest answer is that the weekly cadence is convention, not pharmacology.
Is the loading phase necessary?
There is no trial evidence that a loading phase improves outcomes, because no such trial exists. It is a borrowed concept from other compounds.
Can TB-500 be stacked with BPC-157?
The two are frequently combined in community "repair" protocols on a theory of complementary mechanisms, but the combination has not been tested for safety or efficacy in people. See our stack guide for how that pairing is framed — and why the absence of human data matters.
Sources
- Goldstein AL, et al. "Thymosin β4: a multi-functional regenerative peptide." Expert Opin Biol Ther. 2012;12:37–51.
- Crockford D, et al. "Review of the clinical pharmacology of thymosin β4 and utility as a therapeutic." Ann N Y Acad Sci. 2010;1194:179–189.
- RGN-259 (Lacripep, thymosin β4) ophthalmic trial — ClinicalTrials.gov NCT03784768.
- U.S. FDA — 503A bulk drug substances list update and Category 2 removals, April 15, 2026; PCAC meeting notice for July 23–24, 2026.
Medical disclaimer: Education only, not medical advice. TB-500 is investigational and not approved for human use. Dosing figures reflect community reports, not a recommendation. Do not self-administer; consult a licensed clinician. The only verified-safe path to treatment is an FDA-approved medicine under a clinician's supervision.