TB-500 (Thymosin Beta-4 Fragment)
TB-500 is a synthetic version of a region of thymosin beta-4, a naturally occurring 43-amino-acid protein found in nearly all human cells. Thymosin beta-4 plays a central role in tissue repair by promoting cell migration, blood vessel formation, and reducing inflammation. TB-500 is widely used for accelerating recovery from muscle, tendon, and ligament injuries, and it is one of the most popular peptides stacked alongside BPC-157.
FormBlends Peptide Context
Reviewed May 14, 2026Read TB 500 peptide guide with the practical follow-up in mind. If the topic involves peptide therapy, the next useful step is usually to verify evidence strength, access rules, pharmacy pathway, total cost, and the personal safety details that only a clinician can review.
- Confirm whether the page is discussing approved care, compounded access, off-label use, or research-only context.
- Check the date, evidence quality, safety limits, and whether newer clinical or regulatory updates may change the answer.
- Ask a licensed clinician how the information applies to your history, medications, labs, goals, and risk profile.
Clinical decision snapshot
TB-500 authority snapshot
TB-500 is evaluated by mechanism, evidence quality, regulatory status, practical access, and safety questions a licensed clinician would need to review before use.
Evidence signal
Early clinical or translational evidence
Regulatory reality
Reinstated for compounding (Feb 2026)
Safety screen
Temporary lethargy or fatigue, Headache, Injection site discomfort should be reviewed in context.
This page currently connects to 9 source-backed evidence items through visible references or structured citation data.
Decision path
What is the supervised-review path for TB-500?
TB-500 should be evaluated by evidence quality, safety status, source quality, dosing context, and whether the goal fits a legitimate clinical pathway. This page is a research and decision aid, not a self-prescribing guide.
- Peptide
- TB-500
- Category
- Recovery
- Evidence
- Early clinical or translational evidence
- FDA status
- Not FDA approved
Step 1
Check evidence level
TB-500 has zero completed human clinical trials. All published research is from animal models and cell culture. The animal data is consistently positive for wound healing and tissue repair, but the lack of any human data means the evidence remains preliminary. One clinical trial (NCT06217237) is currently recruiting, which could change this picture.
Review evidenceStep 2
Screen safety context
Temporary lethargy or fatigue, Headache, Injection site discomfort should be discussed in light of history, dose, and source.
Check side effectsStep 3
Confirm access route
If FormBlends offers access, review the product page and provider pathway before deciding.
Review product accessTissue repair hub
TB-500 should be framed around repair biology and evidence limits
TB-500 is searched as a recovery peptide, but the best page is not a shortcut claim. It should explain thymosin beta-4 signaling, cell migration, inflammation and tissue repair hypotheses, then separate research interest from patient-specific clinical decision-making.
Decision question for TB-500
Is the reader comparing recovery peptides after a real diagnosis, or looking for a substitute for proper injury care?
Peptide evidence layer
Evidence read
The useful evidence read is mechanism first, then limits. TB-500 content should make clear when claims come from thymosin beta-4 biology, animal models, user reports, or actual human evidence.
Safety watch
Readers should not use peptide research pages to delay evaluation for tears, fractures, infection, autoimmune disease, chronic pain, or training injuries that need imaging and rehabilitation.
Conversion fit
A provider-review CTA works best when it asks about injury type, timeline, prior imaging, medications, training load, and recovery goals before any treatment discussion.
Last updated: April 3, 2026
Typical Dosage
2-2.5 mg injected subcutaneously twice per week during loading phase (4-6 weeks), then 2 mg once per week for maintenance.
Administration
Subcutaneous injection, Intramuscular injection
Typical Cost
$120-250/month
FDA Status
Not FDA Approved
Half-Life
Estimated at several hours based on animal pharmacokinetic data. No human PK studies exist.
Onset of Action
Animal studies show measurable tissue changes within 1-2 weeks. Practitioners typically report clinical improvements at 4-6 weeks.
Bioavailability
Subcutaneous injection is the standard route. Some practitioners use intramuscular injection near injury sites.
About TB-500
TB-500 is a synthetic version of a 43-amino-acid peptide called thymosin beta-4 (Tbeta4), which is naturally produced by the thymus gland. The full protein has a molecular weight of 4,921 Da. CAS number for thymosin beta-4: 77591-33-4. TB-500 specifically refers to a fragment or synthetic analog used in research settings.
Thymosin beta-4 is one of the most abundant intracellular proteins in the human body. It binds to actin monomers (G-actin) and plays a direct role in cell migration, which is one of the first steps in tissue repair. When tissue is damaged, cells at the wound edge need to physically move into the injured area. Thymosin beta-4 facilitates that movement.
The research on TB-500 is extensive in animals but nonexistent in humans. That's the honest picture. A 1999 study in the Journal of Investigative Dermatology (PMID: 10469321) was one of the first to show accelerated wound healing in rats. A 2004 paper in Nature (PMID: 15229613) demonstrated that thymosin beta-4 could reduce cardiac scar tissue after heart attacks in mice. And a 2001 study in PNAS (PMID: 11553776) showed it accelerated corneal wound healing. These are high-quality journals publishing consistently positive results.
But here's the thing that most peptide websites won't tell you: there are zero completed human clinical trials for TB-500 or thymosin beta-4 as an injectable treatment. One trial (NCT06217237) is currently recruiting as of 2026, which could be the first real human data. Until that publishes, everything we know comes from animal models and cell culture.
The compound is popular in veterinary medicine, particularly for racehorses with tendon injuries. Multiple equine studies have shown positive outcomes, and it's one of the most commonly detected peptides in horse racing doping tests.
Practitioners who prescribe TB-500 typically use a loading phase of 2-2.5 mg injected subcutaneously twice per week for 4-6 weeks, followed by a maintenance phase of 2 mg every 1-2 weeks. The injection is usually given near the injury site when targeting a specific area, though some use abdominal subcutaneous injection.
TB-500 is almost always stacked with BPC-157. The theory (supported by anecdotal practitioner reports but not controlled studies) is that BPC-157 promotes blood vessel formation while TB-500 promotes cell migration, creating complementary healing pathways.
Lyophilized TB-500 should be stored at -20C. Reconstitute with bacteriostatic water by adding it slowly against the vial wall. Don't shake or vortex. Store reconstituted vials at 2-8C and use within 21 days.
How TB-500 Works
TB-500 works primarily by upregulating actin, a cell-building protein involved in cell migration and proliferation. By sequestering G-actin and promoting its polymerization, TB-500 enables cells to move toward injury sites more rapidly. It also promotes angiogenesis, reduces pro-inflammatory cytokines, and has been shown to reduce scar tissue formation by influencing the expression of matrix metalloproteinases.
Receptor targets:
Benefits
- Promotes rapid cell migration to injury sites
- Accelerates muscle, tendon, and ligament healing
- Reduces chronic and acute inflammation
- Promotes new blood vessel growth in damaged tissue
- Reduces scar tissue and fibrosis formation
- Supports cardiac tissue repair after ischemic events in animal models
- Improves flexibility and range of motion during recovery
What Does the Research Say?
TB-500 has zero completed human clinical trials. All published research is from animal models and cell culture. The animal data is consistently positive for wound healing and tissue repair, but the lack of any human data means the evidence remains preliminary. One clinical trial (NCT06217237) is currently recruiting, which could change this picture.
Thymosin beta4 accelerates wound healing
Journal of Investigative Dermatology, 1999 · DOI · PubMed
First study showing thymosin beta-4 accelerated dermal wound healing in rats by promoting cell migration and reducing inflammation
Thymosin beta-4 promotes cardiac cell migration, survival and cardiac repair following myocardial infarction
Demonstrated thymosin beta-4 reduced scar size and improved cardiac function after heart attack in mice
PubMed evidence trail
Research sources used to frame this page
For TB-500, FormBlends checks the page topic against primary trials, systematic reviews, guidelines, and current PubMed-indexed literature where available. These citations are context, not a claim that every study applies to every patient.
Multifunctionality and Possible Medical Application of the BPC 157 Peptide
Used to frame BPC-157 as an investigational peptide with mixed preclinical and limited human evidence.
PubMed
Gastric pentadecapeptide BPC 157 and its role in accelerating musculoskeletal soft tissue healing
Supports cautious tissue-repair context without presenting BPC-157 as an approved therapy.
PubMed
beta-Thymosins
Background source for thymosin biology and tissue-repair mechanisms.
PubMed
Thymosin beta 4 and the eye: the journey from bench to bedside
Shows how thymosin beta-4 evidence differs by route, tissue, and clinical application.
PubMed
Potential Side Effects
- Temporary lethargy or fatigue
- Headache
- Injection site discomfort
- Mild nausea
- Head rush or lightheadedness shortly after injection
Drug Interactions
| Compound | Interaction | Severity |
|---|---|---|
| Anticoagulants (warfarin, heparin) | TB-500 promotes angiogenesis and cell migration, which could theoretically affect wound healing dynamics in patients on blood thinners. No direct studies, but caution is reasonable. | moderate |
Who Is TB-500 For?
Women
No sex-specific data exists. Animal studies haven't shown sex-dependent differences in healing response.
Adults Over 50
Theoretical benefit for age-related wound healing decline, but no human data in any age group. Some practitioners start with lower loading doses in older patients.
Athletes
Widely used in equine and veterinary sports medicine for tendon and ligament injuries. Banned by WADA. Several high-profile doping cases have involved TB-500.
Regulatory Status
FDA Approved
No
Compounding Legal
Yes
2026 HHS Status
Reinstated for compounding (Feb 2026)
TB-500 was one of the 14 peptides reinstated for compounding in February 2026. It had been restricted during the 2023 FDA peptide restrictions.
Last verified: 2026-04-06
Stacking Options
TB-500 is commonly stacked with the following peptides for enhanced results:
Conditions Addressed
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