TB-500

What is TB-500?

TB-500 is a synthetic version of the active region of thymosin beta-4, a natural protein found in nearly every cell in your body. Where BPC-157 is usually aimed at a single injury, TB-500 is promoted for more systemic, whole-body recovery. As with most peptides in this category, the mechanism is well characterized but the human evidence for injected TB-500 is thin, resting mostly on animal and cell research plus the clinical work done on its parent protein.

How TB-500 works

The active sequence of TB-500 centers on a short actin-binding domain (the LKKTETQ motif) taken from thymosin beta-4. Thymosin beta-4 is the body's main G-actin sequestering protein, meaning it binds monomeric actin and regulates how the cytoskeleton assembles. That control over actin is what drives cell migration, so in wound models TB-500 promotes cells moving into injured tissue, encourages new blood-vessel growth, and dampens inflammation. Because thymosin beta-4 is everywhere in the body, the appeal is a systemic rather than localized repair signal.

What the research shows

Thymosin beta-4 itself has a real preclinical and even clinical track record, especially in corneal and cardiac repair, which is covered on the full-length page. Injected TB-500, the fragment sold as a research chemical, is a narrower story: most of its direct evidence is animal and in-vitro work on muscle, tendon, skin, and cardiac healing. There are no large human trials of TB-500 specifically for athletic recovery. The mechanism is credible and the parent molecule is genuinely studied, but the fragment's human benefit is not established.

Dosage and how it is used

There is no clinically established dose. Community protocols commonly cite around 2 to 2.5 mg twice weekly during an initial loading phase, then less frequent maintenance dosing, all by subcutaneous injection. These figures come from anecdote and animal extrapolation rather than dose-finding trials, so they should be read as what people report doing, not as a validated protocol.

→ How to reconstitute TB-500: calculator, units to draw & storage

Side effects and safety

Long-term human safety data for TB-500 is lacking. The most concrete real-world risk is sourcing: TB-500 almost always comes from unregulated research-chemical suppliers, so purity and dosing accuracy vary. As with other pro-repair, pro-angiogenic peptides, the theoretical concern in anyone with active or suspected cancer applies here too. It is worth knowing that TB-500 appears on the World Anti-Doping Agency prohibited list, which matters for tested athletes.

• Research depth: extensive for the parent protein; injected TB-500 evidence is mostly preclinical.
• No long-term human safety data. Purity risk from unregulated sourcing.
• Banned in tested sport (WADA). Not FDA-approved for human use. Verify status independently.

Frequently asked questions

References

• A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 for Treating Corneal Wounds. ClinicalTrials.gov (parent molecule).
• Engineered Tandem Thymosin Peptide Promotes Corneal Wound Healing. IOVS / ARVO Journals.