How does TB-500 work?

The proposed mechanism is tied to thymosin beta-4 biology. The source links the LKKTETQ region to G-actin binding, cytoskeletal remodeling, and migration of cells into damaged tissue. It also reports anti-inflammatory and pro-angiogenic findings in laboratory models. A key limitation is that a short synthetic fragment may not mirror all actions of the full thymosin beta-4 protein.

Is TB-500 FDA approved?

No. The supplied source lists TB-500 as not FDA approved and describes its current status as preclinical with no human clinical trials for the fragment. It also notes FDA Category 2 status with pending reclassification to Category 1 under an April 15, 2026 HHS announcement, remaining Category 2 until a formal FDA rule, with PCAC review dated July 23-24, 2026.

What typical dose is reported for TB-500?

The source gives community-reported dosing, not clinical guidance: 2-2.5 mg twice weekly during loading, then 2.5 mg once weekly for maintenance, with a listed loading range of 2-10 mg per week. It also lists subcutaneous or intramuscular injection and a frequency of 2x weekly for 4-6 weeks, then 1x weekly.

Healing Preclinical - animal studies only

TB-500

Also known as: Thymosin Beta-4 fragment (LKKTETQ), Thymosin Beta-4, Fragment

At a glance

PeptiGuide dataset · reviewed Aug 2026

What it is

Synthetic thymosin beta-4 fragment researched for repair biology, with evidence still largely preclinical for TB-500 itself.

Status

Preclinical

Evidence level: animal studies

Typical dose

2–2.5mg

Subcutaneous or intramuscular injection

Researched for

Muscle recovery, wound healing, injury rehabilitation

Trial progress

PrePreclinical
IPhase I
IIPhase II
IIIPhase III
IVPhase IV
FDAFDA approved

Preclinical - Promising animal research, limited human data

Use the tools

In plain language

Synthetic associated with the active region of thymosin beta-4; many products reproduce LKKTETQ, residues 17 to 23.
Researched for muscle recovery, wound healing, and injury rehabilitation.
Evidence level supplied as Animal Studies, mapped here to .
Source status: preclinical, no human clinical trials for the TB-500 fragment, and not FDA approved.
Community-reported typical dose: 2-2.5 mg twice weekly during loading, then 2.5 mg once weekly maintenance; administration listed as or intramuscular injection.

How it's thought to work

TB-500 is presented as a synthetic based on the thymosin beta-4 active region. The supplied source identifies LKKTETQ, residues 17 to 23, as the short sequence commonly reproduced in TB-500 products and ties that region to G-actin binding. Through this actin-related pathway, thymosin beta-4 research connects cytoskeletal remodeling with cell migration into wound areas. The source also reports anti-inflammatory and pro-angiogenic activity in lab models. The main uncertainty is translational: evidence from full-length thymosin beta-4 does not prove that a 7-amino-acid fragment will reproduce the parent molecule's full biological profile.

What the research shows

Where the research stands

The supplied research summary places TB-500 mainly in a evidence category and says most of the stronger evidence concerns full-length thymosin beta-4 rather than the TB-500 fragment. It reports animal findings in wound, scar, tendon, skin, and cardiac injury models. For human data, the source discusses RegeneRx programs using thymosin beta-4 forms: RGN-259 eye drops in a placebo-controlled Phase 3 neurotrophic keratopathy study, where corneal healing was reported in 6 of 10 treated patients versus 1 of 8 on placebo, and RGN-352 injection, which reached Phase 2 in a cardiac program before a manufacturing hold. These programs are not presented as human efficacy trials of the 7-amino-acid TB-500 fragment. For TB-500 as a fragment, the source states there are no completed, published human efficacy trials for muscle or tendon repair and mentions a recently listed cardiovascular biomarker study as early-stage.

What it shows

✓ Animal studies

Promising animal research, limited human data

△ Limitations

Animal study doses may not translate directly to humans.

Bottom line: Preclinical - No human clinical trials. FDA Category 2 (pending reclassification to Category 1 per April 15, 2026 HHS announcement; remains Category 2 under current law until formal FDA rule; PCAC review July 23-24, 2026) Not FDA Approved

Typical dosing

CommunityCommunity dataset

2–2.5 mg

twice weekly (loading), then 2.5 mg once weekly (maintenance)

2 mgfull range seen10 mg

Community-reported schedule. Source describes a loading period intended to raise tissue levels, a maintenance period, and common stacking with BPC-157 for injury-recovery contexts; this is not a clinical recommendation.

Research dosing

Animal studies onlyAnimal studies only - may not translate to humans

Doses observed in studies

2-2.5 mg twice weekly

Preclinical Research - Animal studies on Thymosin Beta-4 wound healing

Animal study doses may not translate directly to humans.

Duration: 4-6 weeks loading, then maintenance
Administration: Subcutaneous or intramuscular injection

Timing & administration

Best time to take

Morning or evening

2-3 times per week

Food recommendation

With or without food

Why this timing?

The source characterizes timing as flexible because TB-500 is described as having a long half-life; maintaining a consistent schedule is presented as more important than choosing a specific time of day.

Possible side effects

Not everyone experiences these. Individual responses vary with dose, duration, and personal factors.

Generally well-tolerated in preclinical studies
Injection site reactions
Headache
Fatigue
Nausea
May trigger histamine release
Theoretical risk of facilitating tumor cell migration
Contraindicated with active cancer or cancer history
Limited long-term safety data
WADA prohibited at all times

Not everyone experiences side effects, and severity can vary by context, purity, route, and individual health factors.

Sources

PubMed ClinicalTrials.gov FDA.gov

Frequently asked questions

TB-500 is described as a synthetic peptide modeled on the active region of thymosin beta-4. The source says many products center on LKKTETQ, residues 17 to 23, which is associated with actin binding and cell movement. Its research positioning is mainly around muscle recovery, wound healing, and injury rehabilitation, but the supplied evidence emphasizes that completed human trials for the TB-500 fragment itself are essentially absent; much of the human evidence discussed involves full-length thymosin beta-4.

Reported items in the source include general tolerability in preclinical studies, injection site reactions, headache, fatigue, and nausea. Additional cautions listed are possible histamine release in people with MCAS or histamine sensitivity, limited long-term safety data, a theoretical concern related to tumor cell migration because thymosin beta-4 is upregulated in metastatic cancers, a contraindication note for active cancer or cancer history, and WADA prohibition at all times on the 2025 list.

Sequence

Leu-Lys-Lys-Thr-Glu-Thr-Gln

One open dataset

Every fact on this page - doses, side effects, references - comes from the same PeptiGuide dataset that powers the Tracker, Compare, and the Lab.

Browse the dataset

Save to my research list Get updates on TB‑500

Educational resource, not medical advice. Talk to your clinician before acting on anything here.

Community discussion

Comments are moderated before they appear. Keep it evidence-focused.

TB-500

In plain languageIn plain language

How it's thought to workHow it's thought to work

What the research showsWhat the research shows

Typical dosing

Research dosing

Timing & administrationTiming & administration

Possible side effectsPossible side effects

SourcesSources

Frequently asked questionsFrequently asked questions

What does TB-500 do?