TB-500
Thymosin Beta-4 (TB-500)
TB-500 is a research-peptide name for synthetic thymosin beta-4, a 43-amino-acid peptide the body makes that is involved in cell migration and tissue repair; some products sold as TB-500 may contain only a short fragment of it. It is used in practitioner protocols for soft-tissue injuries, often alongside BPC-157. Evidence for injected TB-500 comes from animal and cell studies, and there is no human dosing data.
Quick reference
How TB-500 is dosed in practice
The usual schedule has two phases. Loading: 5 mg injected SubQ every 5 days for 4 weeks. Maintenance: 2.5 mg every 5 days for another 4 weeks. A full course is about 8 weeks, followed by a break.
Every 5 days is the standard interval in practitioner protocols. This guide does not list injections more often than every 5 days or doses above 5 mg.
Where the numbers come from: no human trial has tested injected TB-500 for injuries or set a dose. Thymosin beta-4 itself has been tested in small human trials mostly as eye drops and a skin gel. The schedule above is practitioner convention.
Work out the units to draw with the reconstitution calculator and how long a vial lasts with the vial duration calculator.
How TB-500 works
TB-500 binds G-actin, a building block of the cell's internal scaffolding, which in lab studies helps cells migrate toward injury sites. This differs from BPC-157, which is thought to act mainly through new blood-vessel growth.
Animal studies also report anti-fibrotic effects (less scar tissue), lower inflammatory signaling and faster wound closure, and a mouse study found thymosin beta-4 helped heart cells survive and migrate after injury. These are animal and cell findings, not human results.
Practitioners often pair it with BPC-157 on the idea that the two mechanisms complement each other: BPC-157 builds the road (blood vessels), TB-500 directs the traffic (cell migration). That pairing has not been tested in a human trial.
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.
- 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 (1 mL) = 2,500 mcg (2.5 mg) — maintenance dose
- • 200 IU (2 mL) = 5,000 mcg (5 mg) — loading dose, the whole vial
- • A 100-unit syringe holds 1 mL, so for a single-syringe 5 mg dose reconstitute with 1 mL instead (5,000 mcg/mL; 100 IU = 5 mg)
Synergy stack
TB-500 + BPC-157 — the most common pairing
Practitioners often add BPC-157 (200 mcg–1 mg SubQ daily) during the TB-500 course, on the idea that BPC-157's blood-vessel effects and TB-500's cell-migration effects complement each other. This comes from animal data and practitioner experience; the combination has not been tested in people.
BPC-157 dose
200 mcg–1 mg SubQ daily
BPC-157 duration
4–12 weeks (often alongside the 8-week TB-500 course)
Safety + side-effect profile
There is no human safety trial for injected TB-500. Effects people report are mostly mild:
Unknown, not ruled out: long-term effects, and effects on the liver, hormones or heart, have not been studied in humans. Avoid with: active or recent cancer (thymosin beta-4 promotes cell migration and blood-vessel growth in lab studies), pregnancy, breastfeeding. Use caution after a recent head injury.
Interaction notes: commonly combined with BPC-157 and GHK-Cu, without interaction studies. Use caution with immunosuppressants. TB-500 is banned in tested sport (see FAQ).
- • Tiredness or lethargy in the first week of loading
- • Occasional injection-site soreness
- • Mild headache during loading in some users
Frequently asked
What is TB-500?
TB-500 is a research-peptide name for synthetic thymosin beta-4, a 43-amino-acid peptide involved in cell migration and tissue repair; some products sold as TB-500 may contain only a fragment of it. It is used in practitioner protocols for soft-tissue injuries, often with BPC-157. There is no human dosing data for injected TB-500.
What is the typical TB-500 dose?
Loading: 5 mg SubQ every 5 days for 4 weeks. Maintenance: 2.5 mg every 5 days for another 4 weeks. These are practitioner conventions — there is no human dosing data for TB-500 — and this guide does not list doses above 5 mg or injections more often than every 5 days.
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 (1 mL) = 2.5 mg and 200 IU (2 mL) = 5 mg. For a 5 mg dose in a single syringe, reconstitute with 1 mL instead. Refrigerate; use within about 4 weeks.
Should I run TB-500 alone or stack it?
Many practitioners pair TB-500 with BPC-157 because their proposed mechanisms differ — BPC-157 mainly through blood-vessel growth, TB-500 through cell migration. Whether the combination works better than either alone has not been tested in people.
Are there TB-500 side effects?
Reported effects are mostly mild: tiredness in the first week of loading, injection-site soreness, mild headache. There is no human safety trial, so long-term risks are unknown.
Is TB-500 safe for ongoing maintenance?
Long-term use hasn't been studied. The usual course is about 8 weeks in total — 4 weeks of loading, then 4 weeks of maintenance at 2.5 mg every 5 days — followed by a break rather than continuous use.
Is TB-500 banned in sport?
Yes. The World Anti-Doping Agency (WADA) prohibits thymosin beta-4 and its derivatives, including TB-500, at all times (section S2, peptide hormones and growth factors). Tested athletes should not use it.
Can TB-500 cause cancer?
There is no human evidence that TB-500 causes cancer, but there is also no long-term human data. Because thymosin beta-4 promotes cell migration and blood-vessel growth in lab studies, avoid it with active or recent cancer.
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.
Cited research
Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther, 2012.
Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature, 2004.
Page updated · How we grade evidence
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