TB-500
Thymosin Beta-4 (TB-500)
A synthetic version of Thymosin Beta-4, a naturally-occurring 43-amino-acid peptide. Drives cell migration, actin binding, and anti-fibrotic effects — making it the canonical synergy partner for BPC-157 in soft-tissue, ACL, and rotator-cuff recovery protocols.
Quick reference
How TB-500 works
TB-500 binds G-actin and promotes actin polymerization, which drives directed cell migration to injury sites. This is mechanistically distinct from BPC-157's angiogenesis-first approach — TB-500 doesn't build new blood vessels, it sends repair cells where they need to go.
Secondary effects include anti-fibrotic action (reduces scar tissue formation during healing), suppression of inflammatory chemokines, and enhanced wound contraction. Practitioner reports describe particular benefit in chronic injuries where scar tissue is already a barrier to range-of-motion recovery.
Stacked with BPC-157, the combination is widely considered the gold-standard recovery protocol: BPC-157 builds the road (vasculature), TB-500 directs the traffic (cell migration). The two peptides have complementary mechanisms with no documented antagonism.
Reconstitution math
- Remove the flip-off cap from the 5 mg vial. Wipe the rubber stopper with an alcohol pad.
- Draw 2 mL of bacteriostatic water into a sterile syringe.
- Inject slowly down the vial wall — never directly onto the powder.
- Swirl gently. Do not shake (TB-500 is more shake-sensitive than BPC-157).
- Refrigerate. Stable approximately 4 weeks at 2–8°C.
Dose math
5 mg vial + 2 mL bac water → 2,500 mcg per mL.
On a 100-unit insulin syringe (1 IU = 0.01 mL):
- • 100 IU = 2,500 mcg (2.5 mg)
- • 200 IU = 5,000 mcg (5 mg)
- • Loading dose typically draws the entire 1 mL = 2,500 mcg
Synergy stack
TB-500 + BPC-157 — the canonical synergy stack
TB-500 alone is effective but slow-starting. Adding BPC-157 (500 mcg–1 mg subQ daily) provides the angiogenesis foundation that TB-500's cell-migration action then exploits. Together, recovery timelines compress 30–50% vs either compound alone in practitioner reports.
BPC-157 dose
500 mcg–1 mg subQ daily
BPC-157 duration
4–6 weeks (matches TB-500 loading)
Safety + side-effect profile
Generally well-tolerated. Most reported effects are mild:
Not documented: hepatotoxicity, hormonal disruption, or significant cardiovascular changes at standard doses. Contraindications: active cancer therapy (TB-500's pro-migration action is theoretically concerning in oncology contexts), pregnancy, lactation.
Interaction notes: stacks well with BPC-157, GHK-Cu, and most growth-hormone-axis peptides. Caution stacking with multiple anti-fibrotics simultaneously — diminishing returns and theoretical impaired wound contraction at high cumulative doses.
- • Mild fatigue / lethargy in the first 5–7 days of loading
- • Occasional injection-site soreness (less common than BPC-157)
- • Transient mild headache reported in some loading-phase users
Frequently asked
What is TB-500?
TB-500 is a synthetic version of Thymosin Beta-4, a naturally-occurring 43-amino-acid peptide. It promotes cell migration via actin binding, drives anti-fibrotic effects, and is canonically stacked with BPC-157 for soft-tissue recovery.
What is the typical TB-500 dose?
Loading phase: 2.5–5 mg subcutaneous (or intramuscular) every 3–4 days for 4–6 weeks. Maintenance: 2.5 mg weekly until full recovery. Some practitioners run 10 mg loading doses for severe acute injuries — this is supportable but not strictly necessary.
How do I reconstitute TB-500?
5 mg vial + 2 mL bacteriostatic water → 2,500 mcg/mL. On a 100-unit insulin syringe, 100 IU = 2,500 mcg (full mL), 200 IU = 5,000 mcg. Refrigerate after reconstitution; stable approximately 4 weeks.
Should I run TB-500 alone or stack it?
Most practitioners stack TB-500 with BPC-157 for synergistic effects. The two peptides have complementary mechanisms — BPC-157 drives angiogenesis (new blood vessels), TB-500 drives cell migration (repair cells use those new vessels). Recovery timelines compress 30–50% vs either compound alone in practitioner reports.
Are there TB-500 side effects?
Generally well-tolerated. Reported effects: mild fatigue or lethargy in the first 5–7 days of loading, occasional injection-site soreness, transient mild headache. Not documented: hepatotoxicity, hormonal disruption, or cardiovascular changes at standard doses.
Is TB-500 safe for ongoing maintenance?
Yes — practitioner protocols routinely use 2.5 mg weekly for 8–12 weeks of maintenance after initial loading. Continuous high-dose use beyond 16 weeks is not well-supported in the literature; cycling is recommended.
Is TB-500 banned in sport?
Yes. WADA classifies TB-500 (Thymosin Beta-4) as a prohibited substance under S2.5 (growth factors). Tested athletes should not use it. Recreational and clinical use is governed by local research-chemical regulations.
Can TB-500 cause cancer?
There is no clinical evidence linking TB-500 to cancer. However, because TB-500's mechanism includes promoting cell migration, its theoretical risk in active oncology contexts is non-zero — practitioner consensus is to avoid TB-500 in patients with active or recent cancer treatment until the literature is more developed.
Protocols using TB-500
Outcome-driven stacks with phased dose schedules and cited PMIDs.
Head-to-head comparisons
Cited side-by-side breakdowns that include TB-500.
Related compounds
Often researched, stacked, or compared with TB-500.
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