TB-500
Thymosin Beta-4 fragment
A synthetic fragment of thymosin beta-4, a naturally occurring protein involved in actin regulation and cell migration. Where BPC-157 is used locally, TB-500 is used for whole-body recovery signalling.
- Category
- Repair & Recovery
- Half-life
- Reported as several hours for the fragment, with tissue effects persisting far longer
- Cycle length
- 3–4 week loading phase, then maintenance
- Level
- intermediate
Overview
Thymosin beta-4 is found in almost every human cell and plays a central role in actin sequestration, cell migration and tissue remodelling. TB-500 is a shortened, more stable fragment of that protein. Its following in the recovery space comes from the observation that it appears to travel systemically and concentrate at sites of damage, making it attractive for injuries that are diffuse or difficult to inject near.
How it works
Tb4 upregulates actin, the protein that gives cells their shape and drives movement. By increasing actin availability, it appears to promote cell migration to damaged tissue, support new blood-vessel formation and reduce fibrous scar formation. It also interacts with the extracellular matrix, which is why it is discussed in connective-tissue contexts.
Reported benefits
- Systemic rather than local repair signalling
- Tendon and ligament recovery reports
- Reduced scar-tissue formation in preclinical models
- Flexibility and range-of-motion improvements reported anecdotally
Reported benefits describe what the published literature and user reports suggest — not a promise of outcome for any individual.
Dosing reference
Reported protocols load at roughly 2–2.5 mg twice weekly for three to four weeks, then reduce to a maintenance dose of about 2 mg per week. Subcutaneous or intramuscular administration is the norm.
TB-500 is described much more often in loading-then-maintenance structures than in steady daily dosing, because of its longer apparent activity window. The figures above document that convention; they are not an established human dose.
Community-reported: 2–2.5 mg twice weekly for two to four weeks, then 2–2.5 mg monthly as maintenance, frequently alongside 250–500 mcg per day of BPC-157. Site irritation and post-dose flu-like feelings are the most reported downsides.
These figures are what people report using in public communities. They have not been studied, verified or checked against certificates of analysis, and they are not a recommendation, a prescription or a target to aim for.
Where the reported amounts come from
Amounts are reproduced for education only. Doses from trials cannot be assumed to suit anyone else, and community-reported amounts are frequently wrong. Self-administering unapproved compounds carries serious risk.
The research picture
Preclinical work shows consistent improvements in wound closure, reduced scarring and faster recovery from induced musculoskeletal injury. Human data is essentially limited to small studies of the parent protein in ophthalmic and cardiac contexts — with different dosing, routes and formulations. Anyone reading a confident human protocol for TB-500 online is reading extrapolation dressed as evidence.
Primary sources
Preclinical & non-clinical data
Preclinical work covers wound healing, corneal repair, cardiac tissue after restricted blood flow, and tendon and muscle injury models in rodents. The actin-binding mechanism is well characterised in cells. The human safety picture is the notable part: US regulators have cited a cardiac safety concern when restricting compounding use of thymosin beta-4, which is a reminder that animal healing data does not carry over automatically.
Non-clinical data comes from cells and animals unless stated otherwise. It answers whether a compound is worth studying in people — not whether it is safe or effective in them.
What users report
Reports cluster around stubborn shoulder, elbow and knee injuries and around flexibility and post-training recovery. The typical account is a loading phase of several weeks followed by infrequent maintenance, very often stacked with BPC-157. What users say they notice: easier return to training, and in some accounts reduced joint ache. What they complain about: a flu-like feeling or headache after a dose, and difficulty telling the peptide apart from the natural healing timeline. There is no controlled human trial of the fragment behind any of it.
Where these reports come from
These are unverified personal accounts collected from public sources. They are not evidence of effectiveness or safety, they have not been independently checked, and they are not a recommendation to use anything described.
Possible side effects
- Injection-site reactions
- Headache reported anecdotally
- Fatigue reported anecdotally
- Possible temporary increase in inflammation at the injury site
Safety notes
Thymosin beta-4 is a known actin-binding protein with documented roles in cell proliferation, and it has been found upregulated in several tumour types. That is a mechanistic red flag rather than proof of harm in this context, but it is a genuine reason for caution in anyone with a cancer history. Not for use in pregnancy.
Stacking
Frequently stacked with BPC-157 for recovery work. Also seen alongside GHK-Cu in connective-tissue protocols, and with Ipamorelin in broader regeneration stacks.
Related compounds
BPC-157
Body Protection Compound 157 — pentadecapeptide
Repair & Recovery
The repair peptide the rest of the field is measured against.
MGF
Mechano growth factor — IGF-1Ec splice variant
Repair & Recovery
A genuine exercise-repair signal with zero human injection data.