Thymosin beta-4 FAQ: common questions answered
A peptide studied for eye conditions and skin wounds; tendon-repair injections lack controlled human evidence.
Also called: Tβ4, TB4, TB-4, Timbetasin, Timbetasin acetate, RGN-259, RGN-137, RGN-352, NL005, a recombinant Tβ4-related product.
Healing and repair peptides · Full-length actin-binding peptide; related recombinant trial formulations.
- Is Thymosin beta-4 FDA-approved? No. RGN eye, skin and IV products remain investigational. No FDA-approved product or label dose was identified.
- How do people take it? Under the skin, every other day. 12 weeks. Source: reported by users, not an established dose.
- What's the difference between Thymosin beta-4 and BPC-157? Thymosin beta-4: a peptide studied for eye conditions and skin wounds; tendon-repair injections lack controlled human evidence. BPC-157: an experimental repair peptide with mostly animal evidence and a few small human reports. Why people pair them: reported for injury recovery. Four knee cases used intra-articular Tβ4 with BPC-157; no controlled trial establishes added benefit.
- Can I take it with BPC-157? Reported for injury recovery. Four knee cases used intra-articular Tβ4 with BPC-157; no controlled trial establishes added benefit. Community subcutaneous use differs from the uncontrolled knee series. Source: reported by users. Ask a doctor before combining anything.
- Is it banned in sport? Yes. It is banned in and out of competition (WADA 2026). Tβ4 and derivatives, including TB-500, are named.
- How long does a mixed vial last? Community users refrigerate mixed powder vials. No validated home-mixed Tβ4 shelf life was found.
Related to Thymosin beta-4
- BPC-157: An experimental repair peptide with mostly animal evidence and a few small human reports.
- TB-500: A short piece of thymosin beta-4 with no proven repair benefit in humans.
- GHK-Cu: A copper-binding skin peptide with small topical studies and untested systemic injections.
- AHK-Cu: A copper peptide used in scalp serums, with laboratory findings and weak patent-only human data.
- ARA-290: Experimental peptide studied for small-fiber nerve damage, with uncertain pain relief and safety.
- Ac-SDKP: An experimental repair peptide with old human studies, but no proven healing dose.
Sources
- 503B Bulk Drug Substances List, FDA · FDA · 2026
- Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act, FDA · FDA · 2026
- Cellulitis, NHS · NHS · 2026
- July 23-24, 2026, Meeting of the Pharmacy Compounding Advisory Committee – FDA Briefing Document for TB-500-Related Bulk Drug Substances (TB-500 (free base) and TB-500 acetate), FDA · FDA · 2026
- Medicines, European Medicines Agency · European Medicines Agency · 2026
- MHRA Products | Home, MHRA · MHRA · 2026
- The 2026 Prohibited List, World Anti-Doping Agency · WADA · 2026
- Therapeutic Goods (Poisons Standard—October 2026) Instrument 2026, Australian Government · Australian Government · 2026
- Think twice before injecting peptides bought online: unauthorized products can seriously harm you, Health Canada · Health Canada · 2026
- Thymosin Beta-4, Sport Integrity Australia · 2026
- Anaphylaxis, NHS · NHS · 2023
- Using intramuscular injections in people on oral anticoagulants, NHS Specialist Pharmacy Service · NHS Specialist Pharmacy Service · 2023
- Medical and surgical interventions for neurotrophic keratopathy., Kruoch Z et al. · The Cochrane database of systematic reviews · 2025
- Recombinant human thymosin beta 4 improves ischemic cardiac dysfunction in mice and patients with acute ST-segment elevation myocardial infarction after reperfusion., Zhang Y et al. · Cardiovascular research · 2025
- 0.1% RGN-259 (Thymosin ß4) Ophthalmic Solution Promotes Healing and Improves Comfort in Neurotrophic Keratopathy Patients in a Randomized, Placebo-Controlled, Double-Masked Phase III Clinical Trial., Sosne G et al. · International journal of molecular sciences · 2022
Sources checked: 2026-10-18.
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