TB-500

What is TB-500?

TB-500 is a synthetic peptide based on a fragment of Thymosin Beta-4 (TB-4), a naturally occurring protein found in nearly all human and animal cells.

TB-4 plays a central role in building and recycling actin, one of the structural proteins cells use to move and rebuild tissue. TB-500 reproduces the active region of that protein in a more stable synthetic form. It does not occur in this isolated form in nature.

Benefits and uses

What the research shows — most of it in animal models, which is the honest framing for TB-500:

• Soft-tissue and muscle regeneration. The most-studied effect. TB-500 promotes cell migration and the actin regulation that lets tissue rebuild, which speeds recovery in animal injury models.
• Blood-vessel formation. It supports angiogenesis — the growth of new blood vessels into healing tissue — improving the blood supply an injury needs to repair.
• Inflammation modulation. TB-500 dampens inflammatory signaling, part of why it is used during recovery.
• Systemic reach. Because Thymosin Beta-4 is present throughout the body, TB-500 is studied for whole-body cell migration and regeneration rather than purely local repair.

The gap between the volume of anecdote and the volume of human evidence is real. TB-500 has a following built on animal research and athlete reports; rigorous human clinical trials are limited. State that plainly rather than overselling.

How it works

TB-500 works largely by regulating actin, the protein that drives cell movement. By promoting cell migration to the site of an injury, it helps the cells that rebuild tissue reach where they are needed.

It also supports angiogenesis and modulates inflammation. The combined effect is faster, better-supplied tissue repair across muscle, tendon, and other soft tissue.

Dosage and administration

Typical protocols in the literature and clinical practice use subcutaneous injection, often run in a loading-then-maintenance pattern: a higher loading dose over the first 4–6 weeks, then a lower maintenance dose.

These are not official dosing guidelines — there is no FDA-approved TB-500 product — and dosing should be set by the prescribing provider.

Reconstitution (mixing the lyophilized powder with bacteriostatic water) and drawing the right volume on an insulin syringe is where most people make errors.

For a peptide your clinician prescribed and an appropriate pharmacy prepared, use the peptide dosage calculator to convert the prescribed target dose into syringe units for your vial size.

Side effects and safety

TB-500 has shown a favorable safety profile in animal studies. Reported effects in human use are generally mild — injection-site reactions, fatigue, head rush or lightheadedness shortly after a dose.

The honest caveat: long-term human safety data does not exist. Anyone using TB-500 should monitor liver enzymes and kidney function and work with a provider.

Legal status and how to get it in 2026

This is the question most searchers actually have. The status changed this year:

• For several years TB-500 sat on the FDA’s Section 503A Category 2 list, which effectively blocked compounding pharmacies from preparing it.
• On April 15, 2026 the FDA removed TB-500 (and 11 other peptides) from that Category 2 list.
• A Pharmacy Compounding Advisory Committee meeting on July 23–24, 2026 will evaluate whether TB-500 should be formally added to the authorized bulk-substances list compounding pharmacies can use.

Until that process completes, do not treat the advisory review as approval. Products sold online “for research use only” are not approved, manufactured, or quality-controlled for human use, and buying them carries both quality and legal risk.