TB-500 Side Effects: Safety Signals and Warnings
TB-500 safety concerns are compound-specific. The main listed side effects are No adequate human safety dataset was identified for thymosin beta-4 fragment 17-23, FDA cites potential immunogenicity and peptide-related impurity risks for compounded TB-500, and Injection-related infection, contamination, and local-reaction risks depend on product quality and administration conditions. The main warning signals are Not FDA-approved for any indication, Banned by WADA under the category of peptide hormones, growth factors, and related substances - prohibited for all competitive athletes, and Human full-length thymosin beta-4 trials do not establish safety for the shorter TB-500 fragment.
Direct Answer
Direct evidence for TB-500 fragment 17-23 is preclinical. A 2026 rat tendon study was positive, but the human trials commonly cited online tested full-length thymosin beta-4, a different molecule. TB-500 should not be described as a Phase 2-validated healing peptide.
- Evidence grade
- Level C
- Research status
- Preclinical
- Category
- Healing & Recovery
- Evidence context
- Preclinical study of tendon healing and thymosin-derived repair signaling
Reported Side Effects
- No adequate human safety dataset was identified for thymosin beta-4 fragment 17-23
- FDA cites potential immunogenicity and peptide-related impurity risks for compounded TB-500
- Injection-related infection, contamination, and local-reaction risks depend on product quality and administration conditions
Warnings
- Not FDA-approved for any indication
- Banned by WADA under the category of peptide hormones, growth factors, and related substances - prohibited for all competitive athletes
- Human full-length thymosin beta-4 trials do not establish safety for the shorter TB-500 fragment
- Long-term fragment-specific toxicity, immunogenicity, and carcinogenicity are unknown
Known or Plausible Interactions
- Anticoagulants (Tβ4's pro-angiogenic activity may theoretically affect wound vascularization in anticoagulated patients)
- Immunosuppressants (potential interaction via shared NF-κB pathway modulation)
- Other growth-promoting peptides (additive effects not studied)
Regulatory Context
TB-500 fragment 17-23 is not FDA-approved for any indication. FDA lists compounded thymosin beta-4 fragment among substances that may present significant safety risks because of potential immunogenicity, peptide-related impurities, and the absence of identified human exposure data. WADA prohibits thymosin beta-4 and its derivatives, including TB-500, at all times under section S2.
Evidence Snapshot
| Evidence grade | Level C |
|---|---|
| Research status | Preclinical |
| Best supported outcomes | Wound Healing (Level C), Hair Growth (Level C), Cardiac Repair (Level D), and Anti-Inflammation (Level D) |
| Primary citation count | 9 |
| Last reviewed | 2026-08-27 |
Quick Answers
What are the side effects of TB-500?
TB-500 safety concerns are compound-specific. The main listed side effects are No adequate human safety dataset was identified for thymosin beta-4 fragment 17-23, FDA cites potential immunogenicity and peptide-related impurity risks for compounded TB-500, and Injection-related infection, contamination, and local-reaction risks depend on product quality and administration conditions. The main warning signals are Not FDA-approved for any indication, Banned by WADA under the category of peptide hormones, growth factors, and related substances - prohibited for all competitive athletes, and Human full-length thymosin beta-4 trials do not establish safety for the shorter TB-500 fragment.
What is the evidence level for TB-500?
TB-500 is rated Level C. Its current research status is Preclinical.
What is TB-500 best known for?
Preclinical study of tendon healing and thymosin-derived repair signaling.
Where can I read the full TB-500 evidence review?
The full evidence review is available at https://examinepeptides.com/library/tb-500.
Related Guides
How to Cite This Page
ExaminePeptides. "TB-500 Side Effects: Safety Signals and Warnings." Last reviewed 2026-08-27. https://examinepeptides.com/answers/tb-500-side-effects-safety/
This static answer page is built for fast indexing and direct citation. It summarizes the matching full evidence review and links back to primary sources where the source database includes them.