TB-500
A synthetic peptide corresponding to the active actin-binding region of Thymosin Beta-4, sold for tissue repair, flexibility and recovery. Marketed heavily to athletes and in veterinary/equine circles, but human efficacy rests on animal models and anecdote. Not approved for human use; note that TB-500 and full-length Thymosin Beta-4 are related but not identical.
01 Overview
TB-500 refers to a fragment (often the Ac-LKKTETQ actin-binding sequence) of Thymosin Beta-4 (TB4), a naturally occurring peptide involved in cell migration and wound healing. Full-length TB4 has been studied clinically for dermal wounds, corneal injury and cardiac repair with mixed results; the research-chemical 'TB-500' sold to consumers is typically the shorter fragment and has not itself been through those trials.
Users take TB-500 for tendon and muscle recovery, joint mobility and hair regrowth. The rationale comes from TB4's documented roles in angiogenesis and cell migration in animal models. There are no controlled human trials of the fragment marketed as TB-500, no human pharmacokinetic data, and dosing is entirely convention-based. It is banned in sport by WADA.
02 Mechanism
Thymosin Beta-4 sequesters G-actin and promotes cell migration, angiogenesis and downregulation of inflammation, which in animal models accelerates wound and tissue healing. The TB-500 fragment is presumed to share the actin-binding activity; its behaviour in humans is unconfirmed.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Loading anecdotal | 2–2.5 mg/wk | SubQ | Common self-reported loading dose split across the week for several weeks. No clinical basis. |
| Maintenance anecdotal | 2–2.5 mg/wk | SubQ | Reduced to a maintenance schedule (e.g. every 1-2 weeks) after loading, per user convention. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Improved tissue recoveryThymosin Beta-4 accelerates wound, muscle and cardiac repair in animal models; the consumer fragment is untested in human trials. | Preclinical | ||
| Increased flexibility / reduced joint stiffnessFrequently reported by users; no controlled evidence. | Anecdotal | ||
| Angiogenesis and anti-inflammatory activityDocumented for full-length TB4 in vitro and in animals. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Theoretical tumour-promotion riskBecause TB4 promotes angiogenesis and cell migration, there is a theoretical concern about supporting tumour growth or metastasis; unproven in either direction and no human safety data exists. | Moderate | Unquantified | Unconfirmed | |
| Injection-site reactionsLocal redness, transient fatigue or head-rush reported after injection. | Mild | Common | Anecdotal |
06 Commonly used with
What tb-500 is combined with, and why. This is about intent rather than safety — the interactions table below covers what is dangerous. Nothing here is listed without what it costs.
| Compound | Frequency | Purpose & trade-off |
|---|---|---|
| Stacked compounds | ||
| BPC-157healing stack | The standard counterpart — TB-500's systemic cell-migration/flexibility effects are paired with BPC-157's localised angiogenic repair to cover both sides of a soft-tissue injury.Trade-off: Neither has meaningful human trial data, so running both simply compounds the unknowns and the injection burden without any proven added benefit. | |
| Somatropinlow-dose HGH | Added in advanced recovery protocols to raise IGF-1 and support the connective-tissue and muscle repair TB-500 targets.Trade-off: HGH brings fluid retention, joint stiffness, insulin resistance and real cost, and there is no human evidence the combination outperforms GH alone for healing. | |
| Ipamorelin + CJC-1295GH secretagogue combo | A cheaper way than exogenous GH to nudge endogenous GH/IGF-1 upward alongside TB-500 during a repair block.Trade-off: It layers speculative GH-axis stimulation on a speculative peptide, adding water retention and appetite/glucose effects for a synergy that is theoretical only. | |
| Support & ancillaries | ||
| Structured rehab / physiotherapyloading protocol | Progressive loading is run alongside TB-500 because mechanical stimulus is the best-evidenced driver of tendon and muscle remodelling.Trade-off: It is time-consuming and, being the part that actually has evidence, can make the peptide's contribution impossible to distinguish from normal recovery. | |