TB-500

TB-500 is a synthetic peptide derived from the active region of thymosin beta-4 (Tβ4), a naturally occurring 43-amino acid protein found throughout the human body that plays a critical role in tissue repair, wound healing, and cellular regeneration. Research indicates TB-500 promotes cell migration, reduces inflammation, supports angiogenesis (new blood vessel formation), and accelerates recovery from soft tissue injuries. It has gained significant popularity among athletes, bodybuilders, and biohackers seeking enhanced recovery from musculoskeletal injuries, tendon damage, and general tissue repair. Typical dosing protocols involve 2–5 mg administered weekly via subcutaneous or intramuscular injection, with initial loading phases often lasting 4–6 weeks followed by maintenance dosing. Users commonly report noticeable improvements in mobility and recovery within 2–4 weeks, with optimal benefits building over several months of consistent use.

What Is TB-500?

TB-500 is a synthetic fragment corresponding to the active region of thymosin beta-4, specifically the amino acid sequence Ac-LKKTETQ. Thymosin beta-4 was first isolated from the thymus gland in 1966 by researchers A.L. Goldstein and A. White, though it was later discovered to be present in high concentrations throughout various tissues including the spleen, lungs, brain, and heart.

The peptide's popularity stems from its unique ability to upregulate cell-building proteins such as actin, which is essential for cell structure, movement, and tissue repair. Unlike many compounds that act locally, TB-500 possesses a low molecular weight and unique molecular structure that allows it to travel through tissues systemically, potentially reaching injured areas throughout the body.

Primary human-use benefits attributed to TB-500 include accelerated wound healing, reduced inflammation, enhanced flexibility, improved muscle recovery, and support for tendon and ligament repair. The peptide has also demonstrated cardioprotective properties in preclinical research, with studies showing it can reduce infarct size and improve cardiac function following myocardial injury.

How It Works

Actin Regulation and Cell Migration

The primary mechanism of TB-500 centers on its ability to regulate actin, a protein essential for cell structure and movement. By binding to G-actin (globular actin) and blocking actin polymerization, TB-500 promotes the reorganization of the cellular cytoskeleton, which is critical for cell migration to injury sites. This actin-sequestering function enables cells to move more efficiently toward damaged tissues, accelerating the repair process.

Anti-Inflammatory Effects

TB-500 demonstrates significant anti-inflammatory properties through multiple pathways. Research has shown that thymosin beta-4 sulfoxide, produced by monocytes in response to certain stimuli, blocks neutrophil chemotaxis and possesses potent anti-inflammatory activity. The peptide also reduces macrophage infiltration at injury sites, which helps modulate the inflammatory response and may contribute to decreased scar formation and fibrosis.

Angiogenesis Promotion

TB-500 supports the formation of new blood vessels (angiogenesis), which is essential for delivering oxygen and nutrients to healing tissues. Studies have demonstrated that the peptide promotes endothelial cell migration and differentiation, contributing to improved vascularization of damaged areas. This mechanism is particularly relevant for cardiac repair, where enhanced blood vessel formation can support recovery following ischemic injury.

Stem Cell Mobilization

Research indicates TB-500 promotes the mobilization, migration, and differentiation of stem and progenitor cells, which can form new blood vessels and regenerate tissue. This property may explain the peptide's broad regenerative effects across multiple tissue types.

Dosage Protocols

Dosing protocols for TB-500 typically follow a two-phase approach: an initial loading phase followed by a maintenance phase.

Loading Phase: Most protocols recommend 2.0–2.5 mg administered subcutaneously or intramuscularly every other day, or 4–10 mg weekly (divided into 2–3 doses), for 4–6 weeks.

Maintenance Phase: Following the loading period, dosing typically reduces to 2–5 mg once or twice weekly to maintain therapeutic effects.

Cycling Considerations: Some practitioners recommend cycling TB-500 with periods of use followed by breaks, though specific cycling protocols vary. A common approach involves 4–6 weeks of active use followed by 2–4 weeks off before resuming if needed.

It is important to note that no standardized dosing protocols have been established through clinical trials for human use, and these recommendations are derived from anecdotal reports and extrapolation from research settings.

How to Use / Administration

TB-500 is typically administered via subcutaneous or intramuscular injection. Subcutaneous injections are most common and involve injecting into the fatty tissue beneath the skin, often in the abdominal area, thigh, or upper arm.

Administration Guidelines:

Start with a lower dose and gradually increase to the target dose to assess tolerance. Rotate injection sites regularly to reduce irritation and prevent tissue damage at any single location. Injections are typically performed once daily during loading phases or 2–3 times weekly during maintenance. Some users inject closer to the injury site, though the peptide's systemic distribution means this may not be necessary.

Proper sterile technique is essential, including cleaning the injection site with alcohol, using new sterile needles for each injection, and ensuring hands are clean before handling supplies.

Results Timelines

Individual responses to TB-500 vary based on factors including injury severity, overall health, and activity levels. However, general timelines reported by users include:

Weeks 1–2: Some users report initial reductions in inflammation and mild improvements in comfort at injury sites.

Weeks 2–4: Many individuals begin noticing improvements in mobility, recovery speed, and energy levels.

Weeks 4–8: More substantial improvements in tissue repair, flexibility, and functional recovery are commonly reported during this period.

Months 2–6: Long-term benefits often continue to build with consistent use, particularly for chronic injuries or conditions requiring extended healing time.

Research Evidence

Thymosin beta-4 and its derivatives have been studied in various preclinical and clinical contexts. Phase II clinical trials have evaluated TB4 for dermal wound healing, with results demonstrating accelerated repair in patients with pressure ulcers, stasis ulcers, and epidermolysis bullosa wounds. These trials concluded that TB4 is safe, well-tolerated, and shows promise for skin regeneration applications.

Cardiac research has shown particularly promising results. Studies in animal models demonstrated that TB4 administration following coronary artery ligation enhanced myocyte survival and improved cardiac function. Research in porcine models of ischemic heart disease has further supported the therapeutic potential of thymosin beta-4 for cardiac applications.

Neurological research has explored TB4's neuroprotective and neurorestorative effects, with studies suggesting potential applications for traumatic brain injury treatment.

However, it is important to note that most human-relevant research has focused on the parent compound thymosin beta-4 rather than the TB-500 fragment specifically, and large-scale clinical trials for musculoskeletal applications in humans remain limited.

Stacking

TB-500 is frequently combined with BPC-157 (Body Protection Compound-157) in what is commonly called the "Wolverine Stack" due to the purported synergistic healing effects.

TB-500 + BPC-157: This combination is popular because the peptides appear to work through complementary mechanisms. BPC-157 tends to provide more localized healing effects and stimulates collagen synthesis, while TB-500 offers systemic recovery support and promotes cellular migration and angiogenesis. When stacked, typical protocols involve standard doses of each peptide administered separately, often at different times of day.

Additional Stack Options: Some users combine TB-500 with growth hormone secretagogues (such as Ipamorelin or CJC-1295) or other recovery-focused peptides like GHK-Cu for comprehensive healing support.

Reconstitution, Storage & Prep

TB-500 typically comes as a lyophilized (freeze-dried) powder that requires reconstitution before use.

Reconstitution: Add bacteriostatic water to the vial containing the lyophilized powder. The amount of water determines the concentration—for example, adding 2 mL of bacteriostatic water to a 5 mg vial creates a concentration of 2.5 mg/mL. Inject the water slowly along the inside wall of the vial rather than directly onto the powder. Gently swirl (do not shake vigorously) until the powder is fully dissolved.

Storage: Unreconstituted TB-500 should be stored in a cool, dry place, ideally refrigerated. Once reconstituted, the solution must be refrigerated at 2–8°C (36–46°F) and is typically stable for 3–4 weeks. Never freeze reconstituted peptide solutions. Protect from light and heat exposure.

Preparation: Use insulin syringes for accurate dosing. Calculate the volume needed based on your target dose and the concentration of your reconstituted solution.

Side Effects

TB-500 is generally considered well-tolerated based on available research and anecdotal reports. Thymosin beta-4 has demonstrated a favorable safety profile in clinical trials, with minimal reported adverse effects.

Commonly Reported Side Effects:

Injection site reactions including temporary redness, irritation, or mild discomfort are the most frequently reported issues. Some users report temporary fatigue or lethargy, particularly during initial use. Headaches have been occasionally reported.

Potential Concerns:

Laboratory studies have suggested that thymosin beta-4 may play a role in helping certain cancers spread, though no direct evidence links TB-500 use to cancer development in humans. Long-term safety data in humans remains limited, and the effects of extended use are not well characterized.

Legal Status / FDA

TB-500 is not approved by the U.S. Food and Drug Administration (FDA) for any medical use in humans. The FDA has classified TB-500 (thymosin beta-4) as a "Substance with Safety Concerns," prohibiting its use in compounding pharmacies under the 503A and 503B bulk drug substance regulations.

In the United States, TB-500 exists in a regulatory gray area. It can be legally purchased and possessed as a "research chemical" not intended for human consumption, but it cannot be legally marketed or prescribed as a therapeutic agent. Recent FDA actions have restricted the compounding and prescribing of many peptides, including TB-500, limiting access through traditional medical channels.

Sports / WADA

TB-500 and thymosin beta-4 are prohibited substances under the World Anti-Doping Agency (WADA) Prohibited List. They fall under categories S0 (Non-Approved Substances) and S2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics).

Thymosin beta-4 and its derivatives, including TB-500, were explicitly added as examples of prohibited substances in the 2018 WADA Prohibited List update. Athletes subject to anti-doping regulations who test positive for TB-500 face severe penalties, including competition bans and disqualification of results.

The prohibition applies both in-competition and out-of-competition, meaning athletes cannot use TB-500 at any time during their competitive careers if they are subject to WADA-compliant testing programs.

Conclusion

TB-500 represents a compelling peptide option for individuals seeking enhanced tissue repair and recovery support. Its mechanisms—including actin regulation, anti-inflammatory effects, angiogenesis promotion, and stem cell mobilization—provide a multi-faceted approach to healing that has generated significant interest in both research and practical applications.

While preclinical research and early clinical trials have demonstrated promising results, particularly for wound healing and cardiac applications, the lack of large-scale human trials for musculoskeletal uses means that much of the evidence supporting TB-500's benefits remains preliminary. Users should approach this peptide with appropriate caution, understanding both its potential benefits and the limitations of current scientific knowledge.

For those who choose to use TB-500, proper sourcing, reconstitution, storage, and administration practices are essential for safety and efficacy. Consultation with a knowledgeable healthcare provider is advisable, particularly for individuals with pre-existing health conditions or those taking other medications.

FAQ

What is the difference between TB-500 and thymosin beta-4?
TB-500 is a synthetic peptide fragment corresponding to the active region of thymosin beta-4 (specifically the sequence Ac-LKKTETQ). Thymosin beta-4 is the full 43-amino acid naturally occurring protein. TB-500 was developed to harness the regenerative benefits of the active site while being more practical for therapeutic use.

How long does it take for TB-500 to work?
Most users report initial improvements within 2–4 weeks, with more substantial benefits developing over 4–8 weeks of consistent use. Timelines vary based on injury severity, individual physiology, and dosing protocols.

Can TB-500 be taken orally?
TB-500 is typically administered via injection (subcutaneous or intramuscular) because peptides are generally degraded in the digestive system when taken orally. Injectable administration ensures the peptide reaches systemic circulation intact.

Is TB-500 safe?
Clinical trials of thymosin beta-4 have demonstrated it is safe and well-tolerated at therapeutic doses. However, long-term safety data specifically for TB-500 in humans is limited, and potential risks from unregulated products include contamination and inconsistent dosing.

Can I use TB-500 if I'm a competitive athlete?
No. TB-500 is prohibited by WADA and most sports governing bodies both in-competition and out-of-competition. Athletes subject to drug testing should not use this peptide.

Should I inject TB-500 near the injury site?
While some users prefer injecting near injury sites, TB-500's low molecular weight allows it to travel systemically throughout the body. Research suggests beneficial effects occur regardless of whether the peptide is administered locally or at a distant site.

How should I store TB-500?
Unreconstituted TB-500 should be refrigerated or stored in a cool, dry place. Once reconstituted with bacteriostatic water, it must be refrigerated at 2–8°C and used within 3–4 weeks.

Can TB-500 be stacked with BPC-157?
Yes, this is one of the most popular peptide combinations, often called the "Wolverine Stack." The two peptides work through complementary mechanisms and are commonly used together for enhanced recovery support.