# TB-500 Dosage in the Research Literature > TB-500 dosage data from published studies: equine anti-doping detection at 10 mg, rodent protocols across mg/kg ranges, and Phase I thymosin beta-4 human safety data. Research context only. Dose ranges, administration routes, and pharmacokinetic data from published animal and human studies on thymosin beta-4 and its synthetic heptapeptide fragment. ## TB-500 Dosage Ranges in Published Studies Published dose data for TB-500 (Ac-LKKTETQ) and the parent thymosin beta-4 protein span a wide range across species and study designs. No randomized controlled trial exists for the TB-500 heptapeptide fragment specifically in humans; dose references come from anti-doping research, equine contexts, animal models, and Phase I trials of the full-length thymosin beta-4 protein. In the equine anti-doping detection study — the most definitive published characterization of TB-500 pharmacokinetics — a single 10 mg dose in horses produced plasma concentrations of 0.02 ng/mL and urine concentrations of 0.01 ng/mL as detected by LC-MS/MS [1]. Published equine and clinical-adjacent (informal human) protocols describe 2–5 mg per injection for TB-500, though no controlled human RCT validates this range [1]. Rodent studies of the parent protein used: topical or intraperitoneal application (wound healing, with keratinocyte stimulation at concentrations as low as 10 pg in vitro [2]); 6 or 30 mg/kg IP at 6, 24, and 48 hours post-injury in traumatic brain injury models — the 30 mg/kg dose showing dose-dependent neuroprotective superiority [14]; and 2–10 mg/kg/day in skin flap viability studies, with dose-dependent Wnt/β-catenin activation [20]. Ligament studies used 1 µg Tβ4 in fibrin sealant applied locally to the injury site [10]. Human Phase I data exist for the full-length thymosin beta-4 (44-amino-acid protein) only. Ruff et al. (2010) administered IV thymosin beta-4 at escalating doses from 42 to 1,260 mg in healthy volunteers and reported no dose-limiting toxicities and a plasma half-life ranging from approximately 0.95 hours at 42 mg to 2.1 hours at 1,260 mg [11]. A separate Phase I study of recombinant human thymosin beta-4 in healthy Chinese volunteers confirmed safety across single and multiple daily doses, with half-lives of 0.5–2.08 hours and no accumulation after 10 consecutive daily doses [12]. These data describe what was administered in specific research protocols. How much TB-500 one should take is not a question this site answers — that determination requires consultation with a licensed clinician, which this site does not provide. ## TB-500 Half-Life and Pharmacokinetics Human pharmacokinetic data specific to the TB-500 heptapeptide fragment are not available in published literature. The plasma half-life reference in the literature derives from Phase I studies of the full-length 44-amino-acid thymosin beta-4 protein administered intravenously in humans: 0.95–2.1 hours across the 42–1,260 mg dose range [11], and 0.5–2.08 hours in the Chinese Phase I cohort [12]. These values reflect IV administration of a larger molecule and are not directly transferable to subcutaneous or intramuscular TB-500. How long TB-500 stays in your system in the context of anti-doping enforcement is a different question from pharmacokinetic half-life. The WADA detection window for TB-500 and thymosin beta-4 in urine and blood is approximately 30–45 days post-administration, measured by LC-MS/MS in accredited anti-doping laboratories [1]. This detection window reflects metabolite accumulation in tissue, not active compound half-life. Athletes competing under WADA-compliant doping control face a potential 2–4 year suspension for a positive test [1]. ## TB-500 Administration Frequency in Research Protocols Published protocols and clinical-adjacent reports describe a loading phase of twice-weekly injections for approximately four weeks, followed by a once-weekly maintenance phase. Daily administration has not been evaluated in controlled trials [1]. Animal studies have used single post-injury doses (e.g., TBI models at 6, 24, and 48 hours post-injury [14]) or repeated daily dosing for vascular models (skin flap at 2–10 mg/kg/day [20]). The Phase I human trials of full-length Tβ4 used escalating single doses and then consecutive daily doses for safety assessment [11, 12]. TB-500 administration protocols described in research do not constitute a clinical dosing recommendation. The frequency and duration of any compound's administration in humans is a medical determination, not a reading this site provides. ## TB-500 Injection Site Protocols in Research Research protocols describe both subcutaneous and intramuscular administration of TB-500 in informal human contexts; the animal literature uses intraperitoneal routes for systemic delivery in rodent models, and intramyocardial injection for cardiac-specific studies [5, 16]. The ligament repair study used direct local application via fibrin sealant to the injury site [10]. Some protocols describe local injection proximal to the site of injury to maximize local tissue concentration; others use systemic administration to test broader whole-body effects. The two approaches are not equivalent and are compared only within their respective study designs. No controlled trial has directly compared local versus systemic TB-500 administration in humans. ## Oral vs. Injectable TB-500 in the Research Literature TB-500 is a peptide and is degraded by gastric and pancreatic proteases when taken orally; no study has demonstrated meaningful oral bioavailability for the Ac-LKKTETQ heptapeptide or the parent thymosin beta-4 protein. Published research protocols use parenteral routes exclusively: intraperitoneal (rodent), intravenous (human Phase I), intramyocardial (cardiac studies), and subcutaneous or intramuscular (equine and informal human contexts) [1, 11, 12]. Oral administration is not supported by the available evidence base. ## TB-500 Reconstitution Methods Described in Research Laboratory protocols for peptide preparation describe reconstituting lyophilized peptide powder with bacteriostatic water using sterile technique to prevent contamination. TB-500 is typically supplied as a lyophilized powder in research contexts; the reconstitution step is a standard laboratory peptide-handling procedure, not a step specific to TB-500's pharmacology. Contamination risk with improperly prepared peptide preparations is a safety consideration noted in the research literature; this is a procedure-quality concern, not a compound-specific toxicity. ## Can TB-500 Be Administered Daily? Published research protocols use twice-weekly or weekly injection schedules rather than daily administration. The loading-phase twice-weekly schedule and maintenance-phase once-weekly schedule described in clinical-adjacent and equine contexts have not been validated in randomized controlled trials; daily dosing has not been studied at all in clinical-grade protocols [1]. Animal studies using daily dosing (skin flap models at 2–10 mg/kg/day [20]) address vascular ischemia endpoints and use dose ranges far above informal human protocols. ## TB-500 Study Duration: Loading and Maintenance Phases Published protocols reference a four-week loading phase followed by a four-week maintenance phase. Long-term cycle duration has not been evaluated in controlled human studies. Animal studies range from single-dose post-injury administration (TBI: one post-injury injection series [14]) to multi-week repeated dosing (skin flap: 2-week treatment periods [20]; ligament repair: four-week histological endpoints [10]). ## TB-500 Onset of Effect in Research Models Animal studies document measurable tissue-repair outcomes within two to four weeks of injection. In ligament repair, superior collagen organization was documented histologically at the four-week endpoint [10]. In TBI models, sensorimotor and cognitive improvements were measured at two to four weeks post-treatment [14]. In wound healing, significant reepithelialization differences between treated and control rats were evident at day 4 and day 7 [2]. Timing in humans is extrapolated from preclinical data — no validated human data exists on onset of any effect for TB-500 specifically. --- A velvet-bound digest of the thymosin beta-4 literature — peer-reviewed, gold-ruled, and held by no clinic and no vendor.