TB-500

weak data

Also seen as: Thymosin Beta-4, TB4

The Dose Guy’s verdict

Sep 1, 2026
2 sources

I run it alongside BPC-157, most people do, and the pairing is the community default for structural healing. But TB-500 standing on its own receipts is a thinner story than BPC-157. Zero human data. The one rat tendon study showed real significance on mechanical strength, and the community experience is broad, but the only study that tested the BPC-157 and TB-500 combination found no additional benefit over either alone. You are buying collective experience and a plausible mechanism, not a proven outcome.

Would I take it?Cautious yes, as part of the stack.

What it is

A synthetic seven-amino-acid fragment of thymosin beta-4, a naturally occurring protein involved in cell migration and tissue repair. The pitch is that TB-500 carries the actin-binding region of the parent protein, the part that drives cell migration and wound repair. That pitch got more complicated when a 2024 metabolism study found that the parent TB-500 peptide itself had no documented biological activity, and only one of its metabolites showed wound-healing effects in fibroblasts. The mechanism story is not settled.

What is settled is the community’s use case: TB-500 circulates systemically where BPC-157 works more locally, and the two together are the default healing stack for anything structural. The equine world adopted it first, horse racing banned it first, and the human peptide community picked it up from there.

What the research shows

No human trials. Zero. Everything below is animal or in-vitro work. Read it as “interesting,” not “evidence it works in you.”

No human trial, no human case series, no human pharmacokinetics. Everything below is animal or cell work:

In rats after Achilles tendon transection, TB-500 at 60 mcg/kg/day for four weeks significantly increased maximum load to failure versus control. Histology scores were also significantly better, with Bonar p=0.016 and Movin p=0.017. Combined TB-500 and BPC-157 produced no additional benefit over either agent alone.Jt Dis Relat Surg 2026 · rat RCT · n=32

Among TB-500 and its tested metabolites, only Ac-LKKTE showed significant wound-healing activity in fibroblasts. The parent peptide itself had no documented biological effects before this study’s own assays. No cytotoxicity was found for parent TB-500 or its metabolites.J Chromatogr B 2024 · metabolism + fibroblast assay

No human orthopaedic efficacy data for TB-500 exists in PubMed. Clinical dose, frequency, and treatment duration remain unknown.as of Aug 2026

Realistic protocols

The community runs a loading phase followed by maintenance. Inject subcutaneously anywhere convenient, abdomen or deltoid, and rotate. TB-500’s value is systemic reach, so site does not matter the way it does with BPC-157.

Loading runs 2 to 2.5 mg twice a week for the first four to six weeks. Drop to once a week or biweekly when you notice improvement, less pain on the movement that was the problem, better range of motion, less swelling after a session. If nothing moves by week six, it is probably not going to. If you are stacking with BPC-157, the BPC goes near the injury and the TB-500 goes anywhere. Reconstitute with bacteriostatic water and refrigerate. Keep training through it, light and progressive, the same advice as BPC-157: controlled loading beats total rest.

Thymosin beta-4 products are prohibited by WADA, IFHA, and FEI.

Loading2–2.5 mg 2x/wkFour to six weeks. Front-loads tissue levels for the systemic effect.

Maintenance2–2.5 mg 1x/wkHold or taper to biweekly once improvement plateaus.

The stack+ BPC-157BPC near the injury, TB-500 anywhere. The community default for structural repair.

Duration8–12 weeks totalLoading plus maintenance. Reassess and cycle off.