TB-500 benefits and uses

Evidence at a glance

Each row pairs a reported use with the best published evidence found for it.

Tendon repair in rats

The most direct evidence is an exploratory 2026 study of 32 male rats whose Achilles tendons were cut and surgically repaired.³ The rats were split into four groups of 8: a control group, BPC-157, TB-500, or both.³ Treatment was given by injection into the abdominal cavity for four weeks after surgery.³ Doses are listed on TB-500 dosage.

The TB-500 group had significantly lower, meaning better, total Bonar tissue scores than the control group (p = 0.016).³ Its repaired tendons also withstood a significantly higher maximum load before failing (p < 0.05).³ BPC-157 alone scored numerically better but missed statistical significance on total scores.³ Combining the two gave no added benefit over either one alone.³ The authors say the peptides warrant further study, pending dose-optimization and longer-term studies.³

Wound healing: TB-500 or its breakdown product?

In a 2024 cell study, TB-500 did not significantly speed the closure of scratch wounds in cultured fibroblasts over 8 hours.¹ One of its breakdown products, Ac-LKKTE, produced a small but significant wound closure under the same conditions.¹⁴ The authors suggest that the wound-healing activity reported earlier for TB-500 may be due to this metabolite.⁴ Ac-LKKTE forms as TB-500 loses amino acids one by one from its tail end.¹

An older mouse study found a benefit, but it did not test TB-500.¹ In 26-month-old mice, a version of the peptide without the acetyl group (LKKTETQ) was applied to skin wounds.¹ It increased epidermal closure and collagen content by day 7.¹ FDA cautions that this result cannot be directly extrapolated to acetylated TB-500, and that the study had no dose-response assessment.¹ Weighing the evidence, FDA concluded there is a lack of evidence to evaluate TB-500 for wound healing.¹

Blood vessel growth

The blood-vessel evidence comes from a 2003 cell and tissue study of thymosin beta-4 and synthetic fragments of it, not of TB-500.⁶ In migration tests with human umbilical vein cells and sprouting tests with chick aortic tissue, a peptide of the protein's seven-amino-acid actin-binding motif was about as active as the full protein.⁶ Fragments missing any part of that motif were inactive, so the authors concluded it is essential for thymosin beta-4's vessel-forming (angiogenic) activity.⁶ TB-500 contains LKKTET, the actin-binding region of thymosin beta-4.¹ FDA says it remains to be determined whether actin binding contributes to the effects reported for the LKKTETQ peptide.¹ Those effects include blood-vessel growth, mast cell degranulation and wound healing.¹

Nerve recovery: a 3-patient case series

In 2026, clinicians described 3 patients with injury to the inferior alveolar (lower jaw) nerve.² Each received weekly injections under the lining of the mouth for 4 weeks.² The mix held TB-500, ARA-290, BPC-157 and other medicines.² The patients showed neurosensory recovery during follow-up.⁵

The authors call these hypothesis-generating cases.² With no control group, spontaneous recovery and other confounding factors cannot be excluded, and causality cannot be established.² They add that the outcomes should not be read as evidence that the treatment worked.² ARA-290 has its own profile: ARA-290.

Hair, skin and muscle claims

FDA lists promoting hair growth and increasing muscle growth and tone among the uses TB-500 is marketed for online.¹ For hair, the closest study is a 2004 report on thymosin beta-4, the full parent protein.⁷ It stimulated hair growth in normal rats and mice by activating hair follicle stem cells.⁷ No hair study of TB-500 itself appears in the sources reviewed here.

For muscle, there is no study finding to report: FDA found no article in which TB-500 was given to people.¹ Related overviews: skin and hair research, muscle research and healing research.

Results for thymosin beta-4 are not results for TB-500

Several websites use the two names interchangeably, but FDA states that thymosin beta-4 and TB-500 are not the same substance.¹ The human results below concern the full protein only.

• Dry eye: in a phase 2 trial of 9 patients with severe dry eye, 0.1% thymosin beta-4 eye drops (RGN-259) cut ocular discomfort by 35.1% compared with vehicle at day 56.⁸
• Neurotrophic keratopathy: in a phase 3 trial of 18 patients, complete healing at 4 weeks occurred in 6 of 10 treated patients and 1 of 8 on placebo (p = 0.0656, not statistically significant).⁹ A 2025 Cochrane review concluded, with low certainty, that it may not increase corneal healing.¹⁰
• Venous leg ulcers: in a phase 2 trial of 73 patients, the authors suggested a topical 0.03% dose may speed healing.¹¹ They suggested complete healing could be reached within 3 months in about 25% of patients; the abstract gives no statistical comparison with placebo.¹¹

How to read these findings

The evidence levels in the table mean different things. A cell study tests cells or tissue in a dish. An animal study tests rats, mice or horses. A case series reports a few treated patients without a comparison group, so it cannot show cause and effect.² A controlled trial compares treated people with an untreated or placebo group. TB-500 has results at the first three levels and none at the last.¹²

For the overview, see What is TB-500?. Safety data are on TB-500 side effects, and lab handling is on How to reconstitute TB-500. The research vial is listed under TB-500 for sale.