Healing & Recovery
TB-500
Thymosin Beta-4 fragment · TB4
What it is
TB-500 is a synthetic version of the active region of Thymosin Beta-4, a 43-amino-acid peptide naturally produced in nearly every cell of your body. Thymosin Beta-4 is one of the molecules platelets release at injury sites to kick off the healing cascade. The TB-500 fragment was developed because it's smaller, cheaper to make, and easier to dose than the full protein.
How it works
TB-500's main job is to get cells moving toward damage. Specifically, it:
- Binds actin — the protein cells use to crawl, change shape, and migrate. This makes immune cells, stem cells, and tissue cells move faster and reach injury sites quicker.
- Promotes new blood vessel formation (angiogenesis) so healing tissue gets oxygen and nutrients.
- Reduces inflammation by modulating cytokine signaling.
- Mobilizes stem and progenitor cells to differentiate at injury sites.
It's especially good at soft-tissue injuries because of how it accelerates cell migration into damaged areas.
Benefits
- Soft tissue and muscle recovery
- Tendon and ligament healing (especially when combined with BPC-157)
- Wound healing acceleration (clinical trials in venous stasis ulcers)
- Reduced inflammation and stiffness
- Cardiac tissue repair (active research area)
- Hair regrowth (some users report)
- Skin healing and reduced scarring
Timeline
- Week 1–2
- Loading phase. No dramatic effects yet, but inflammation often starts decreasing.
- Week 3–4
- Most users report meaningful pain reduction and improved range of motion.
- Week 4–6
- Peak structural healing — tendon, ligament, soft tissue regeneration.
- Week 6–8
- End of typical cycle. Maintenance dose can be run for chronic conditions.
Dosing & titration
Loading dose2–5 mg per week, split into 2 doses, for the first 4–6 weeks
Maintenance2–5 mg every 2 weeks after loading phase
Cycle length4–8 weeks loading, then maintenance or off
RouteSubQ injection, can be near injury site
When to titrate upLoading at the higher end (5 mg/week) is appropriate for severe acute injuries. Don't exceed 10 mg/week — no added benefit reported and increases theoretical risks.
Side effects & risks
- Mild fatigue or "head fog" the first few days
- Injection site reactions
- Temporary flu-like symptoms in some users (immune activation)
- Rare: light-headedness during loading
Theoretical concerns: Like BPC-157, TB-500 promotes angiogenesis, so it's contraindicated in active cancer. Banned in WADA-tested professional sports. Long-term human safety data is still limited.
Typical price
$120–$200/mo
5 mg vial from a 503A compounding pharmacy — loading phase typically uses 2 vials/month, maintenance much less.
Studies
- Thymosin beta-4 accelerates wound healing — Foundational study showing wound healing acceleration in animal models. PubMed Journal of Investigative Dermatology, 1999
- The regenerative peptide thymosin β4 accelerates the rate of dermal healing in preclinical animal models and in patients — Phase 2 clinical data in venous stasis and pressure ulcers. PubMed Annals of the New York Academy of Sciences, 2012
- Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications — Comprehensive review of mechanisms and therapeutic applications. PubMed Expert Opinion on Biological Therapy, 2011
- Phase 2 Clinical Trial in Venous Stasis Ulcers (NCT00832091) — Found TB-4 accelerated healing by approximately one month in patients who healed. ClinicalTrials.gov RegeneRx Biopharmaceuticals
- Active TB-500 (17-23 fragment) Phase 1 trial (2025) — Currently recruiting. ClinicalTrials.gov NCT07487363
Educational reference only. Not medical advice. TB-500 is not FDA-approved as a drug. Any use should be under guidance of a licensed prescriber.