TB-500 (Thymosin Beta-4) — Research, Dosing & Price Guide

TB-500 is a synthetic version of the active region (amino acids 17-23) of Thymosin Beta-4, a 43-amino acid protein naturally produced in high concentrations by platelets, wound fluid, and most tissues in the body. It is one of the most widely used healing and recovery peptides, known for promoting tissue repair, reducing inflammation, and accelerating wound healing across multiple tissue types including muscle, tendon, ligament, skin, and cardiac tissue. TB-500 has gained enormous popularity in both the athletic and clinical research communities for its versatile regenerative properties.

TB-500 contains the key actin-binding domain of Thymosin Beta-4 (Tβ4), centered on the sequence LKKTETQ. Its primary molecular function is to sequester monomeric G-actin, preventing its polymerization into F-actin filaments. This may seem counterintuitive for a healing peptide, but the regulation of actin dynamics is fundamental to cell migration — the process by which repair cells (keratinocytes, endothelial cells, fibroblasts, stem cells) move to injury sites. By maintaining a pool of available G-actin and promoting actin filament reorganization, TB-500 dramatically enhances cell motility. In wound healing, TB-500 promotes the migration of endothelial cells and keratinocytes to the wound site, accelerating re-epithelialization and angiogenesis (new blood vessel formation). It upregulates the expression of VEGF (vascular endothelial growth factor), promoting the formation of new capillary networks that supply regenerating tissue with oxygen and nutrients. TB-500 has potent anti-inflammatory properties. It downregulates inflammatory cytokines (IL-1β, IL-6, TNF-α) and chemokines while promoting the M2 (anti-inflammatory, pro-repair) macrophage phenotype over the M1 (pro-inflammatory) phenotype. This shifts the immune response from damage-control to active tissue remodeling. In cardiac tissue, Tβ4/TB-500 has shown remarkable effects — it activates resident cardiac progenitor cells, promotes cardiomyocyte survival after ischemic injury, and reduces fibrosis (scar formation). In hair follicles, it stimulates stem cell migration and differentiation, promoting hair regrowth. TB-500 also upregulates matrix metalloproteinases (MMPs) that remodel the extracellular matrix during tissue repair, and it promotes the production of laminin-5, a key component of the basement membrane.

• Sosne et al. (2002, Journal of Immunology) demonstrated Tβ4 promoted corneal wound healing and reduced inflammation in animal models
• Bock-Marquette et al. (2004, Nature) showed Tβ4 promoted cardiomyocyte survival after ischemic injury and reduced infarct size by 40% in mice
• A study in the Journal of Dermatological Science showed Tβ4 accelerated full-thickness wound closure by 30–50% in rodent models
• Philp et al. (2004, Journal of Investigative Dermatology) demonstrated Tβ4 promoted hair growth by activating follicular stem cells
• Smart et al. (2007, Nature) showed Tβ4 reactivated epicardial progenitor cells in adult hearts, suggesting cardiac regeneration potential
• Crockford (2007, Annals of the New York Academy of Sciences) reviewed Tβ4's role in wound healing and tissue remodeling across multiple organ systems
• Goldstein et al. (2012) demonstrated anti-inflammatory effects via suppression of NF-κB signaling and reduction of pro-inflammatory cytokine expression
• RegeneRx Biopharmaceuticals conducted Phase II trials for eye and skin wound healing with positive results

• Loading phase: 2–2.5 mg subcutaneous injection twice per week for 4–6 weeks
• Maintenance phase: 2–2.5 mg once per week or biweekly after loading
• For acute injuries: 5 mg twice per week for 2–3 weeks, then taper to maintenance
• Subcutaneous injection in the abdominal area; some inject near the injury site though systemic distribution is rapid
• Can also be administered intramuscularly for localized muscle injuries
• Typical full cycle: 6–12 weeks (4–6 week loading + 4–6 week maintenance)
• Some protocols alternate: 2 weeks on, 2 weeks off for extended use
• Best combined with BPC-157 for synergistic healing — different but complementary mechanisms
• No food timing restrictions; inject at a consistent time of day

Known Side Effects

• Generally very well tolerated — TB-500 has a mild side effect profile
• Temporary lethargy or fatigue in the first few days of use (often described as the body diverting energy to repair)
• Head rush or lightheadedness immediately after injection (transient)
• Mild nausea in some individuals, particularly with higher doses
• Injection site redness, swelling, or itching
• Theoretical concern about promoting growth of existing cancers (due to angiogenic and cell-proliferative properties), though no clinical evidence supports this
• Temporary increase in inflammation at injury sites as the healing process activates (sometimes perceived as a flare-up)

Safety Profile

TB-500 has been widely used in veterinary medicine (particularly equine) and in the research community with a favorable safety record. Thymosin Beta-4 is naturally present in all human cells at high concentrations, which provides inherent biocompatibility. No serious adverse events have been reported in published Tβ4 clinical trials for wound healing and dry eye. The primary theoretical concern is related to its angiogenic and cell-proliferative properties — patients with active malignancy should avoid TB-500, as promoting new blood vessel formation could theoretically support tumor growth. However, some research suggests Tβ4 may actually have anti-tumorigenic properties in certain contexts. It is not recommended during pregnancy or lactation due to lack of safety data. No drug interactions are established. TB-500 does not affect hormonal axes (testosterone, GH, thyroid). It has been banned by WADA for competitive athletes.

Week 1–2 (loading): Subtle effects begin. Increased flexibility and reduced stiffness in injured areas. Some users experience temporary fatigue or mild discomfort at old injury sites as the healing process activates. Sleep quality often improves. Week 2–4: Noticeable improvement in injury recovery. Tendon and ligament injuries show reduced pain and improved range of motion. Muscle strains heal noticeably faster. Inflammation at chronic injury sites decreases. Week 4–8: Significant healing progress. Many acute soft tissue injuries show substantial or complete resolution. Chronic injuries continue improving. Hair growth in areas of thinning may become apparent. Skin quality improves — cuts and wounds heal faster. Week 8–12: Full effects are evident. Many chronic injuries show significant improvement or resolution. Joint mobility and flexibility are enhanced. Recovery from training is markedly improved. Transition to maintenance dosing. Post-cycle: Some benefits persist for weeks to months after discontinuation, as structural tissue repairs are maintained. However, the anti-inflammatory and recovery-enhancing effects diminish.

Prices sourced from peptides.gg marketplace. Prices may vary.