TB-500

01 How it works

Thymosin beta-4 helps cells move to where they are needed by regulating actin, part of the cell’s internal scaffolding. In studies it supports new blood vessel growth, tissue regeneration and reduced inflammation. TB-500 is built around the active region of that protein.

02 Common uses

03 Run profile

The same shape as BPC-157: start low, step up in phases, once a day with weekends off. Often run alongside BPC-157 over the same weeks.

04 Pairs well with

05 What to watch for

Injection-site redness or discomfort, occasionally a mild headache or a flat, sluggish feeling. Rotate sites and stay hydrated. Facial or throat swelling, trouble breathing or dizziness need urgent care. Anyone with a personal or family history of cancer should talk to a doctor first — it works partly through tissue-growth signalling and the long-term picture is not settled.

06 Evidence & status

Thymosin beta-4 has been studied in animals (including heart repair) and in some early human trials for wounds and dry eye. Data on TB-500 itself in people is limited.

Not FDA-approved. Recommended 8–6 for the 503A compounding list by an FDA advisory panel in July 2026, a non-binding vote. On 28 October 2026 HHS issued an interim enforcement-discretion policy that lets state-licensed pharmacies and physicians compound single-ingredient TB-500 (injected) while FDA rulemaking continues. It is still not on the 503A list, and there is no final FDA decision.

Sources

1. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applicationsExpert Opinion on Biological Therapy, 2012 · Review
2. Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trialCornea, 2015 · Clinical trial
3. Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitroJournal of Chromatography B, 2024 · Reference
4. TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVDClinicalTrials.gov, 2026 · Trial registry
5. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory CommitteeU.S. Food and Drug Administration, 2026 · Regulator document
6. HHS Draft Policy Eases Enforcement on 6 Compounded PeptidesThe American Journal of Managed Care (AJMC), 2026 · Regulator document
7. Thymosin beta-4 (substance education)Sport Integrity Australia, 2026 · Regulator document
8. The Prohibited ListWorld Anti-Doping Agency, 2026 · Regulator document

Status and sources last checked November 3, 2026. Something out of date? Tell us.

07 How long until it works

There is no human study of TB-500 for the injuries it is used for, so there is no measured answer. What exists is animal work on thymosin beta-4, the parent protein, where wound and tissue repair measures changed over two to four weeks, and early human trials of thymosin beta-4 itself for severe dry eye and skin wounds, which ran over weeks to months.

People using TB-500 for recovery tend to report change on the same timescale as BPC-157, which is why the run profile pairs them over the same six-to-twelve-week block. As with BPC-157: that is the shape of common use, not a result from a trial.

08 TB-500 vs BPC-157

The two are usually weighed against each other, and the honest summary is that neither has a human trial for tendon or muscle injury. The difference people choose on is reach. BPC-157 is taken for one site, and the animal evidence is strongest for localised repair. TB-500 is taken for broader recovery, on the basis of thymosin beta-4’s role in cell movement and new blood-vessel growth, and thymosin beta-4 is the one of the two with human trials behind it, though for eye and skin conditions rather than sport.

TB-500 is a fragment of thymosin beta-4, not the whole protein; in rats it is broken down and cleared within hours, which is one reason doses are daily. The combination (the Wolverine Stack) has one exploratory animal study and no human data.

09 Stacking

BPC-157 is the standard partner, and the two are sold pre-mixed as the Wolverine Stack. No published study has tested the pair in people. The October 2026 HHS compounding policy covers single-ingredient TB-500 only, so a pharmacy cannot supply the combined vial under it.

10 Where it stands legally

TB-500 is not approved by the FDA or any other regulator. In July 2026 the FDA’s advisory committee voted 8–6 to recommend it for the 503A compounding list, against FDA reviewers’ advice, and on 28 October 2026 HHS issued an interim policy under which it will not take enforcement action against licensed pharmacies and physicians compounding single-ingredient injected TB-500 while rulemaking continues. That is a pause in enforcement, not an approval.

For athletes the position is clearer than for most peptides here: WADA’s Prohibited List names thymosin beta-4 and its derivatives, TB-500 included, under S2 (peptide hormones, growth factors and related substances), banned at all times. Sport Integrity Australia states that no therapeutic use exemption would be granted for it.

11 FAQ

Educational information only — not medical advice. The Daily Stack does not sell or supply any products. Talk to a licensed healthcare professional about your own health decisions.