TB-500

Compoundable (Rx)

Tissue Repair Peptides · Healing & Recovery

TB-500 is a synthetic version of Thymosin Beta-4, a naturally occurring 43-amino acid peptide present in almost all human cells.

What is TB-500?

TB-500 is a synthetic version of Thymosin Beta-4, a naturally occurring 43-amino acid peptide present in almost all human cells. It plays a crucial role in tissue repair, cell migration, blood vessel formation, and inflammation reduction. It is widely used for accelerating recovery from injuries.

Also known as: Thymosin Beta-4 Fragment, Tβ4

How Does TB-500 Work?

Upregulates actin, a cell-building protein essential for cell migration and proliferation. Promotes angiogenesis, reduces inflammation by decreasing pro-inflammatory cytokines, and facilitates cell migration to injury sites. Also modulates metalloproteinases involved in tissue remodeling.

Molecular Formula: C212H350N56O78S

Molecular Weight: 4963.44 Da

What is TB-500 Used For?

Tissue repair
Muscle recovery
Inflammation reduction
Wound healing
Cardiac repair

Potential Side Effects

Generally well-tolerated
Injection site irritation
Headache (uncommon)
Temporary lethargy

Contraindications

Active cancer
Pregnancy
Children

FDA Legal Status

United States — FDA

Compoundable (Rx)

Category 1 (restored 2026)

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Head-to-head comparisons:

TB-500 vs BPC-157

Frequently Asked Questions

What is the difference between TB-500 and Thymosin Beta-4?

TB-500 is a synthetic fragment containing the active region of the full-length Thymosin Beta-4 protein. It replicates the key tissue-repair actions of the natural protein but is more practical and cost-effective to produce.

How long does TB-500 take to work?

Most users notice improvements within 2-3 weeks, with optimal results typically seen after 4-6 weeks of consistent use. Acute injuries may respond faster than chronic conditions.

Is TB-500 legal?

As of 2026, TB-500 has been restored to FDA Category 1 in the US, making it available through compounding pharmacies with a prescription. In Canada, it remains a research chemical.

Quick Facts

Legal Status (USA): Compoundable (Rx)
FDA Category: Category 1 (restored 2026)
Evidence Rating: BModerate Evidence (Some Human Data)
Class / Subclass: Tissue Repair Peptides / Healing & Recovery
Administration: subcutaneous, intramuscular
Typical Dosage: 2-5mg twice weekly (loading); 2mg twice weekly (maintenance)
Half-Life: ~6 hours
Year Discovered: 1981

Sources

PubMed 20447411 PubMed 22074417

Last updated: 2026-04-01

Sources & references

Primary sources used for the dosing, mechanism, side-effect, and regulatory claims on this page. Verify time-sensitive information (regulatory status, prescribing details) on the source before relying on it for medical decisions. See our disclaimer.

PubMed PMID 20447411 — peer-reviewed primary literature on TB-500.
PubMed PMID 22074417 — peer-reviewed primary literature on TB-500.
FDA Federal Register — official notice record for FDA regulatory actions and Category 1 / 503A bulk-substance updates.