HomePeptides › Thymosin Beta-4

Thymosin Beta-4

TB4, Tbeta4

Tier 3 · Limited Human Data
Class
Actin-sequestering protein
Molecular target
G-actin
Sequence / structure
43-aa acidic polypeptide
Evidence tier
Tier 3 — Limited Human Data
Category
Tissue Repair & Cytoprotection
Emergency card
Signs something is wrong

Any new or unusual symptom after dosing. Because this compound has little or no human safety data, there is no established list of 'expected' effects to reassure you against — treat anything abnormal as a signal.

What to do now

Stop at the first clearly abnormal reaction and reassess. Keep the vial and lot number in case you need to describe what you actually took.

When it is an emergency

Any severe or fast-worsening symptom — difficulty breathing, chest pain, fainting, severe pain — is a 911 call regardless of the compound.

Any injection — every time

Allergic reaction: hives, swelling of the lips, tongue or throat, wheezing or dizziness can escalate to anaphylaxis within minutes — call 911 immediately. Site infection: spreading redness, heat, swelling, pus or fever is not wait-and-see; an abscess or cellulitis can need drainage or IV antibiotics. Unverified product: grey-market vials are frequently mislabelled or contaminated, so a reaction may be to endotoxin or the wrong contents, not the named compound.

This is not permission or instruction to use this compound. It is harm-reduction information for someone who has already decided to, so that a bad reaction is recognised and treated. When in doubt, get help — embarrassment is survivable.

Biology & mechanism

The full-length molecule, and the one the actual research concerns — a distinction routinely blurred by vendors selling “TB-500”. It is among the most abundant proteins in most cells, binding monomeric G-actin and regulating the polymerisation that drives cell migration. Its effects on angiogenesis, keratinocyte migration and inflammation follow from that role.

What the research actually shows

Reached genuine clinical trials — phase 2 in dry eye disease, venous stasis ulcers and epidermolysis bullosa — which is more than TB-500 can claim. Results were insufficient to carry it to approval. Extensive preclinical work in cardiac and corneal repair.

Regulatory status

Not FDA-approved. Development discontinued. Prohibited in sport (WADA S0).

Safety signals

Trial safety data exist at studied exposures. The pro-angiogenic mechanism carries the same unresolved theoretical concern as BPC-157 — an agent that promotes vessel growth does not choose which tissue benefits.

Clinical trial dosing — what the studies actually used

The full-length protein reached phase 2 (dry eye, venous ulcers, epidermolysis bullosa) at study-defined doses; results did not support approval. No established therapeutic regimen.

Reported from clinical trials or FDA labelling as a matter of record. It is not a recommendation, and for unapproved compounds no dose has been shown safe or effective in humans.

We report study doses, not protocols

Above is what was administered in trials or on FDA labels, reported as fact. We do not convert it into a personal protocol, calculate a dose for your body weight, or tell you what to inject or how to reconstitute it — that decision belongs with a licensed physician. See our editorial policy.

References & further reading

Regulatory status changes. This page reflects our reading of public sources as of July 2026 and should be independently verified before it is relied upon.

Important notice Forge Bioenergy publishes scientific reference information only. Nothing on this site is medical advice, a therapeutic claim, or a recommendation to use any substance in humans. Many peptides described here are not approved by the FDA for any use, and several are approved only for narrow indications under prescription. We do not publish dosing, administration, or usage protocols. Consult a licensed physician before making any medical decision.