By Lee Walpole, founder · Sources checked · Not independently reviewed by a veterinarian
Why it is planned for a future formula.
- Planned for a future Recovery+ formula
- Being evaluated for tissue repair and flexibility
- Will join the powder once it can be made edible and stable
Evidence: Equine doping-control study. See the science below.
TB-500 research so far
- TB-500 copies a short section of thymosin beta-4, a protein mammals make naturally. Natural thymosin beta-4 has been found in dog saliva. That is not evidence that injected TB-500 helps dogs.
- The best animal data come from horse racing laboratories, which gave TB-500 to horses to build a doping test, not to measure healing. A 2025 paper describes thymosin beta-4 as not authorised as a medicine and prohibited in racing and sport.
- A 2024 rat and cell study found that TB-500 itself did not improve wound closure in cell culture. Only one breakdown fragment did. Earlier healing claims may relate to a metabolite rather than the peptide as sold.
- In May 2026 FDA staff found no human clinical studies, no animal toxicity studies and a possible immunogenicity risk, and concluded the evidence weighs against adding TB-500 to the compounding bulks list. An advisory committee later voted narrowly the other way. That vote is non-binding and FDA has not made a final decision.
What is still unknown about TB-500
- Whether TB-500 does anything useful for a dog’s injury, joints or recovery. We found no controlled study of TB-500 in pet dogs for any condition.
- Safe exposure levels and long-term effects in dogs. No acute, repeat-dose, reproductive or cancer safety studies have been published in any species.
- What is actually in a vial labelled TB-500. FDA notes several different salts and peptides are sold under the same name, with no official standard.
What to ask your vet about TB-500
Bring this page and its sources to your veterinarian. Ask whether the research on TB-500 covered dogs like yours, whether it matches the exact formulation being proposed, and what is known about its safety and legal status. Your veterinarian knows your dog’s history.
Common questions about TB-500
No. TB-500 is not an approved animal drug in the US or, as far as we can find, anywhere else, and it is not part of any approved human drug. Products sold online are labelled for research use, which is not a veterinary approval.
We could not find a published study of TB-500 in dogs. The animal research we verified comes from horse racing laboratories studying how to detect it, and from rat and cell work on how it breaks down. None of it measured healing or safety in pet dogs.
Sources
- Ho et al. (2012): detection of TB-500 and its metabolites in horses after administration Equine doping-control study
- Delcourt et al. (2025): thymosin beta-4 levels in racehorses and detection of misuse Equine doping-control study
- Rahaman et al. (2024): TB-500 metabolism in rats and wound-healing activity in cell culture Preclinical metabolism study
- FDA (May 2026): evaluation of TB-500 for the 503A bulk drug substances list US regulatory evaluation
- FDA: bulk drug substances for compounding that may present significant safety risks US regulatory guidance
Educational information, not veterinary advice. Speak with your veterinarian before changing your dog's care. We provide no dosing or treatment recommendations.