EvidenceDPreliminaryVery uncertain: animal or cell studies, or studies in people with several serious weaknesses.
No. Human trials tested full thymosin beta-4 gel on leg ulcers, not TB-500 injections, and no human data show TB-500 heals injuries. Its safety in people is unknown.
Who it's for
No group has a clear benefit; not shown to help injuries.
What to expect
No clear benefit for injuries; leg ulcer healing was only suggested.
Watch out for
Safety in humans is unknown, and it is banned in sports.
What guidelines say
The FDA lists TB-500 among substances that may present significant safety risks in compounding. It has not identified any human exposure data and lacks information on whether it would cause harm1Guideline · 2026Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksCompounded drugs containing thymosin Beta-4, Fragment (LKKTETQ) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation as well as peptide-related impurities. FDA has not identified any human exposure data drug products containing Thymosin Beta-4, Fragment. FDA lack…US Food and Drug Administration. The FDA notes possible immune reactions from clumping of the peptide and from impurities1Guideline · 2026Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksCompounded drugs containing thymosin Beta-4, Fragment (LKKTETQ) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation as well as peptide-related impurities. FDA has not identified any human exposure data drug products containing Thymosin Beta-4, Fragment. FDA lack…US Food and Drug Administration.
What the studies show
A trial of 73 people with venous leg ulcers tested full thymosin beta-4 as a skin gel against a dummy gel (placebo A dummy treatment that looks like the real one, so people can't tell which they got.). Safety looked acceptable and similar to placebo. A 0.03% dose may speed healing, with about 25% fully healed within 3 months2Randomized trial · 2010 · 73 peopleThe effect of thymosin treatment of venous ulcers.Efficacy findings from this Phase 2 study suggest that a Tbeta4 dose of 0. 03% may have the potential to accelerate wound healing and that complete wound healing can be achieved within 3 months in about 25% of the patients, especially among those whose wounds are small to moderate in size or mild to moderate in…Ann N Y Acad Sci. This was an early-phase study, and the benefit was only suggested at one dose.
A design report for a similar trial (72 patients, treated for 84 days) describes the same approach, topical gel plus standard compression care3Randomized trial · 2007 · 72 peopleThymosin beta-4 and venous ulcers: clinical remarks on a European prospective, randomized study on safety, tolerability, and enhancement on healing.The study is ongoing and a total of 21 patients have been enrolled so far in the first treatment group at the lower dose. Patients' compliance and motivated and well-trained teams seem to be the most suitable parameters of a successfully conducted study.Ann N Y Acad Sci. It reports no results.
A review reports that thymosin beta-4 sped skin healing in animals. It also notes early-phase trials in pressure ulcers, leg ulcers and a blistering skin disease, and calls the peptide safe and well tolerated7Review · 2016Thymosin β4 Promotes Dermal Healing.Tβ4 also accelerated the rate of repair in phase 2 trials with patients having pressure ulcers, stasis ulcers, and epidermolysis bullosa wounds. It is safe and well tolerated and will likely have additional uses in the skin and in injured organs for tissue repair and regeneration.Vitam Horm. The author's own work underlies this, so weigh it with care.
Reviews of TB-500 for muscle, tendon and joint injuries find benefit only in animal studies and veterinary use. Human orthopaedic data are lacking4Review · 2026Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.While peptide therapy may possess significant therapeutic and regenerative potential, it is critical that orthopaedic and sports medicine providers understand the current lack of evidence to support the clinical use of these peptides. Importantly, information regarding the indications, dosing, frequency, and duration…Am J Sports Med,5Review · 2026Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance.We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.Sports Med,6Review · 2026Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.Although preclinical studies are promising, there is a current lack of clinical trials. This review integrates current mechanistic insights with orthopaedic relevance, emphasizing safety, efficacy, and future directions for responsible integration into musculoskeletal care.J Am Acad Orthop Surg Glob Res Rev. A scoping review concluded that claimed benefits remain unsubstantiated in human trials8Animal study · 2026Peptide Supplements and Their Therapeutic Applications in Sports Medicine.Despite promising findings in animal studies, the claimed benefits of emerging peptide supplements for musculoskeletal recovery and performance remain unsubstantiated by current human trials. Documented risks include cardiovascular complications and metabolic dysfunction such as insulin resistance. Because of the lack…Am J Sports Med.
Dose, frequency and duration of treatment for injuries are unknown4Review · 2026Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.While peptide therapy may possess significant therapeutic and regenerative potential, it is critical that orthopaedic and sports medicine providers understand the current lack of evidence to support the clinical use of these peptides. Importantly, information regarding the indications, dosing, frequency, and duration…Am J Sports Med. TB-500 is usually injected under the skin or into muscle6Review · 2026Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.Although preclinical studies are promising, there is a current lack of clinical trials. This review integrates current mechanistic insights with orthopaedic relevance, emphasizing safety, efficacy, and future directions for responsible integration into musculoskeletal care.J Am Acad Orthop Surg Glob Res Rev.
A trial of TB-500 against placebo in 80 people with stable heart and artery disease is recruiting11Registered trial · 2026TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVDClinicalTrials.gov. Two completed trials of thymosin beta-4 in pressure ulcers and leg ulcers have posted results that were not reviewed here9Registered trial · 2006Study of Thymosin Beta 4 in Patients With Pressure UlcersClinicalTrials.gov,10Registered trial · 2006Study of Thymosin Beta 4 in Patients With Venous Stasis UlcersClinicalTrials.gov.
Key studies
Study
Who
What it found
Trial, 20102Randomized trial · 2010 · 73 peopleThe effect of thymosin treatment of venous ulcers.Efficacy findings from this Phase 2 study suggest that a Tbeta4 dose of 0. 03% may have the potential to accelerate wound healing and that complete wound healing can be achieved within 3 months in about 25% of the patients, especially among those whose wounds are small to moderate in size or mild to moderate in…Ann N Y Acad Sci
73 people with venous leg ulcers
Gel safe; 0.03% dose may speed healing
Review, 20264Review · 2026Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.While peptide therapy may possess significant therapeutic and regenerative potential, it is critical that orthopaedic and sports medicine providers understand the current lack of evidence to support the clinical use of these peptides. Importantly, information regarding the indications, dosing, frequency, and duration…Am J Sports Med
Orthopaedic peptide literature
TB-500 helped in animals; human data lacking
Scoping review, 20268Animal study · 2026Peptide Supplements and Their Therapeutic Applications in Sports Medicine.Despite promising findings in animal studies, the claimed benefits of emerging peptide supplements for musculoskeletal recovery and performance remain unsubstantiated by current human trials. Documented risks include cardiovascular complications and metabolic dysfunction such as insulin resistance. Because of the lack…Am J Sports Med
Animal and human peptide studies
Benefits unsubstantiated in human trials
Review, 20167Review · 2016Thymosin β4 Promotes Dermal Healing.Tβ4 also accelerated the rate of repair in phase 2 trials with patients having pressure ulcers, stasis ulcers, and epidermolysis bullosa wounds. It is safe and well tolerated and will likely have additional uses in the skin and in injured organs for tissue repair and regeneration.Vitam Horm
Skin healing studies
Full thymosin beta-4 helped animal wounds; early human trials
Safety
The FDA has no human exposure data on TB-500 and cannot say whether it harms people1Guideline · 2026Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksCompounded drugs containing thymosin Beta-4, Fragment (LKKTETQ) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation as well as peptide-related impurities. FDA has not identified any human exposure data drug products containing Thymosin Beta-4, Fragment. FDA lack…US Food and Drug Administration. Compounded versions may carry immune-reaction risk from clumping and impurities1Guideline · 2026Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksCompounded drugs containing thymosin Beta-4, Fragment (LKKTETQ) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation as well as peptide-related impurities. FDA has not identified any human exposure data drug products containing Thymosin Beta-4, Fragment. FDA lack…US Food and Drug Administration. TB-500 remains banned in sports4Review · 2026Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians.While peptide therapy may possess significant therapeutic and regenerative potential, it is critical that orthopaedic and sports medicine providers understand the current lack of evidence to support the clinical use of these peptides. Importantly, information regarding the indications, dosing, frequency, and duration…Am J Sports Med. Unapproved peptides in general carry potential for serious harm because rigorous human safety data are scarce5Review · 2026Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance.We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.Sports Med.
What we don't know
Whether TB-500 injections heal tendon, muscle or other injuries in people.
Whether TB-500 is safe in people, and what dose would be used.
Written by AI from the studies listed, without review by a clinician, and graded with the GRADE method. It can be wrong, so check the studies it cites. Education, not medical advice.