TB-500 quick reference
What is TB-500?
Sold as a short synthetic piece of thymosin beta-4, a natural protein.
People use it for tendon, muscle and soft-tissue recovery.
No human study of TB-500; human trials used the full-length protein.
How TB-500 works
Thymosin beta-4 binds actin, which cells use to move and change shape.
TB-500 is described as acetylated LKKTETQ, the protein's actin-binding site.
Full-length protein sped skin healing in diabetic and aged mice.
Full-length protein promoted hair growth in rats and mice.
What TB-500 is studied for
Repaired rat Achilles tendons were stronger and better organised on TB-500.
Faster healing in diabetic and aged mice (full-length protein).
Hair growth in rats and mice (full-length protein).
72 people: main goals missed, some secondary signs improved (eye drops).
96 patients: no overall scar benefit; smaller scars if dosed within 8 hours.
The short actin-binding piece promoted cell migration and new vessels.
TB-500 dosing protocol
| Item | What is known |
|---|---|
| Human dose of TB-500 | Not established |
| Studied in | Animals (TB-500). People have only received full-length thymosin beta-4. |
| Full-length thymosin beta-4, phase 1b (NCT04555850) | 0.5, 2 or 5 mcg per kg, daily for 10 days, by vein, in 30 healthy adults |
| Full-length thymosin beta-4 eye drops, phase 2 | 0.1% solution for 28 days, 72 people with dry eye |
NCT04555850 tested recombinant human thymosin beta-4 (NL005) from Beijing Northland Biotech; the record posts no results. The eye-drop trial is Sosne 2015. Neither tested TB-500.
Label and trial amounts come from the sources below. Community amounts are what people report; they have not been tested.
Mixing
Bacteriostatic water. Swirl gently, refrigerate. Vial contents vary by seller.
What the research found
Nothing has been published for TB-500 itself. The closest human results are for full-length thymosin beta-4:
Sosne G et al. Clin Ophthalmol 2015 (PMID 26056426); Zhang Y et al. Cardiovasc Res 2025 (PMID 41229390); ClinicalTrials.gov NCT04555850. In the heart-attack trial, scar size was smaller only in the 43 people dosed within 8 hours after the procedure.
TB-500 community experience
What users report. Not tested in trials.
Positive reports
- Easier movement Many report less stiffness within 1–2 weeks.
- Rehab support Shoulder, elbow, knee and tendon users report smoother recovery.
- Whole-body use Users inject at usual sites, not beside the injury.
- Popular with BPC-157 This pairing gets the most praise.
Negative & mixed
- Little change Advanced degenerative injuries often respond poorly.
- Tiredness or headache Short-lived fatigue, headache or lightheadedness.
- Slow tendon change Hard to credit TB-500 for slow healing.
TB-500 stacking
Most common pair. In rats, no added benefit over either alone.
Both tied to tissue remodeling. Not studied together.
Fixed-ratio vials containing TB-500. Not studied as blends.
TB-500 side effects & safety
Common
- No safety data for TB-500 itself in people.
- No adverse events in the 72-person dry-eye trial (full-length protein).
- User reports: redness or soreness at the injection site.
- User reports: tiredness, headache or lightheadedness.
Less common
- Cell-movement and vessel effects raise a theoretical cancer concern.
- Long-term immune, heart and organ safety is unknown.
- Sellers use different forms, so the vial may not match studied material.
Precautions
- Avoid with active cancer or unexplained lumps.
- Avoid in pregnancy or breastfeeding; no safety data.
- Known allergy to thymosin beta-4 or vial ingredients.
- Banned in sport (WADA class S2).
- Injections can bruise; take care with blood thinners.
Our verdict on TB-500
Good animal signal, but no human data on TB-500 itself. Community claims outrun the evidence.
TB-500 FAQ
What is TB-500?
A short synthetic piece of thymosin beta-4 (acetylated LKKTETQ). Vial contents vary by seller.
Is TB-500 the same as thymosin beta-4?
No. Thymosin beta-4 is the full 43-amino-acid protein; TB-500 is a short piece.
Has TB-500 been tested in people?
No. Human trials used full-length thymosin beta-4.
Can athletes use TB-500?
No. WADA lists thymosin beta-4 and derivatives such as TB-500.
Sources
- ClinicalTrials.gov NCT04555850 (recombinant human thymosin beta-4, phase 1b, healthy volunteers)
- Sosne G et al. Clin Ophthalmol 2015, PMID 26056426
- Zhang Y et al. Cardiovasc Res 2025, PMID 41229390
- Goldstein AL et al. Expert Opin Biol Ther 2012 (thymosin beta-4 review), PMID 22074294
- WADA Prohibited List 2026, class S2 (thymosin-beta-4 and its derivatives, e.g. TB-500)
- Drugs@FDA / openFDA search: no thymosin beta-4 product
- Ho EN et al. J Chromatogr A 2012 (TB-500 identified as acetylated LKKTETQ), PMID 23084823
- Sosne G et al. FASEB J 2010 (active sites of thymosin beta-4), PMID 20179146
- Philp D et al. Wound Repair Regen 2003 (diabetic and aged mice), PMID 12581423
- Philp D et al. Ann N Y Acad Sci 2007 (hair growth), PMID 17947589
- Bicer O et al. Jt Dis Relat Surg 2026 (BPC-157 and TB-500, rat Achilles), PMID 42542926