TB-500 Calculator

What Is TB-500?

TB-500 is a synthetic analog of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid protein found at high concentrations in virtually every cell of the human body. The TB-500 designation refers specifically to a 17-amino-acid fragment corresponding to the actin-binding domain of full-length Thymosin Beta-4 (residues 17–23 in the native protein, often referred to as the LKKTETQ sequence). This fragment retains the full biological activity of the parent molecule while being smaller, more synthesizable, and more economically viable for research applications.

Thymosin Beta-4 was originally identified as a thymic hormone involved in T-cell maturation, but subsequent research revealed its primary biological function to be the sequestration and regulation of actin — one of the most abundant proteins in eukaryotic cells and the principal structural component of the cytoskeleton. By binding G-actin monomers and preventing their polymerization into F-actin filaments, Thymosin Beta-4 controls cell shape, motility, and the wound-healing response at the cellular level.

The breadth of TB-500's preclinical evidence is impressive: it has been studied in models of myocardial infarction, stroke, skeletal muscle injury, tendon damage, peripheral nerve injury, corneal healing, and dermal wound closure. It is also one of the most studied peptides for hair follicle biology, with evidence suggesting it can reactivate dormant follicles and accelerate hair shaft elongation. TB-500 does not affect sex hormones, does not suppress the hypothalamic-pituitary axis, and has no known interaction with endocrine systems — making it one of the safer peptides for both male and female research applications.

Mechanisms of Action

TB-500 operates through several distinct and interrelated mechanisms:

• Actin sequestration and cell migration: TB-500 binds G-actin with high affinity, creating a reservoir of unpolymerized actin monomers. This dynamic pool enables rapid cytoskeletal reorganization, which is essential for cell migration into wound beds. Keratinocytes, fibroblasts, and endothelial cells — all of which are central to wound healing — require precisely this kind of actin plasticity to migrate, proliferate, and close wounds efficiently.
• Angiogenesis and endothelial activation: TB-500 promotes endothelial cell proliferation and tube formation, driving the formation of new blood vessels at injury sites. This vascularization response is critical for delivering oxygen, nutrients, and growth factors to healing tissue and for supporting tissue viability in areas with compromised circulation (such as cardiac tissue after infarction).
• Anti-inflammatory signaling: TB-500 downregulates pro-inflammatory cytokines including IL-1β, TNF-α, and NF-κB activity. By shortening the inflammatory phase of tissue repair, it accelerates the transition into the proliferative and remodeling phases of wound healing.
• Anti-apoptotic activity: TB-500 promotes cell survival under stress conditions by activating PI3K/Akt signaling — a major cell survival pathway. This anti-apoptotic effect has been particularly well studied in cardiac and neural tissue, where preventing programmed cell death after ischemic injury is critical for functional recovery.
• Stem cell activation and mobilization: Preclinical evidence suggests TB-500 can mobilize bone marrow-derived progenitor cells and activate local stem cell populations, replenishing tissue-specific cell pools depleted by injury or disease.
• Extracellular matrix remodeling: TB-500 modulates the activity of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), coordinating the breakdown of damaged matrix and its replacement with newly synthesized collagen and proteoglycans. This remodeling function contributes to scar reduction and restoration of tissue elasticity.
• Hair follicle biology: Thymosin Beta-4 is expressed in the outer root sheath of hair follicles and plays a regulatory role in the hair growth cycle. Research indicates it can prolong the anagen (growth) phase, activate resting follicles in the telogen phase, and promote the differentiation of hair follicle stem cells — mechanisms relevant to pattern baldness research and hair recovery after systemic stress.

Dosage Calculation

TB-500 is administered at significantly higher doses than many other research peptides because it works through receptor-mediated mechanisms requiring a threshold tissue concentration. It does not require titration, though starting at the lower end of the range is advisable for new users.

Standard Dosing Parameters

• Conservative dose: 2.0 mg per injection
• Standard therapeutic dose: 2.5 mg per injection
• Higher range: 5.0 mg per injection (experienced users, acute injury)
• Frequency: 2–3 times per week (not daily — its half-life of ~7 days allows for less frequent dosing)
• Typical syringe: 1.0 mL insulin syringe (27–29 gauge, 8–12 mm needle)

Example Calculation: 5 mg Vial with 2 mL BAC Water

Adding 2 mL of bacteriostatic water to a standard 5 mg vial yields a concentration of 2.5 mg/mL.

• 2.0 mg dose: 2.0 ÷ 2.5 = 0.80 mL (80 units on a U100 syringe)
• 2.5 mg dose: 2.5 ÷ 2.5 = 1.00 mL (100 units — full 1 mL syringe)
• 5.0 mg dose: requires 2.00 mL — full vial content in one injection

At the standard 2.5 mg dose administered 2 times per week, one 5 mg vial provides exactly 2 injections. A 10 mg vial at the same protocol provides 4 injections (2 weeks of dosing). Use the TB-500 calculator above to compute volumes for any vial size, reconstitution volume, and target dose.

Protocol Structure

TB-500 protocols often follow a loading and maintenance phase structure:

• Loading phase (weeks 1–4): 2.5 mg, 2–3 times per week. This phase builds tissue-level concentrations and establishes the reparative environment. For acute injuries, the full 2.5–5 mg 3x per week loading approach provides maximum initial concentration.
• Maintenance phase (weeks 5–12): 2.5 mg, once or twice per week. Sufficient to sustain angiogenic and anti-inflammatory effects as healing continues.
• Cycle off: After 8–12 weeks, a 4-week break before resuming. Given the long half-life, concentrations decay slowly and residual activity persists for several weeks after the last injection.

Reconstitution

TB-500 is supplied as a lyophilized powder in sealed vials and must be reconstituted with bacteriostatic water before injection. Use bacteriostatic water — not sterile water or saline — for multi-dose vials, as its benzyl alcohol content inhibits microbial growth and extends the shelf life of the reconstituted solution.

Step-by-Step Reconstitution Protocol

1. Gather supplies: TB-500 vial, bacteriostatic water vial, alcohol swabs, a sterile draw needle (18–21 gauge), and your 1 mL insulin syringe for injection.
2. Wipe the rubber septa of both vials with fresh alcohol swabs. Allow to air-dry for 30 seconds without touching or blowing on the septum surface.
3. Draw 2 mL of BAC water into the draw syringe (for a 5 mg vial). Adjust the volume to suit your preferred concentration if using a different vial size.
4. Insert the draw needle into the TB-500 vial at an angle, directing the tip toward the inner glass wall — not the lyophilized powder. This angle prevents direct high-velocity impact on the powder, which can denature the peptide.
5. Slowly depress the plunger so BAC water runs down the glass wall and makes gentle contact with the powder from below.
6. Swirl gently until the powder dissolves completely. The solution should be clear and colorless. Do not shake, vortex, or tap the vial vigorously.
7. Label the reconstituted vial with the date and concentration (e.g., "TB-500 2.5 mg/mL — reconstituted [date]").

Discard any vial where the reconstituted solution is cloudy, discolored, or contains visible particles. Never inject a solution that does not appear fully clear.

Storage and Shelf Life

• Lyophilized powder (unreconstituted): Store at −20°C for long-term stability (24+ months). Short-term storage at 2–8°C is acceptable for up to 3 months. Protect from light and moisture. Avoid repeated temperature fluctuations during storage, as condensation can compromise the lyophilized cake.
• Reconstituted solution: Refrigerate at 2–8°C. Stable for approximately 28–30 days. Keep the vial upright, away from light, and in the original packaging if possible. Record the reconstitution date on the vial label.
• Do not freeze the reconstituted solution. Freezing causes peptide aggregation and degradation. Once reconstituted, the vial must remain refrigerated continuously.
• Transport: Use an insulated cooler with an ice pack. Commercial insulin travel coolers or medication pouches maintain 2–8°C for 24–48 hours. Avoid exposure to temperatures above 25°C during any travel period.

Side Effects and Safety Profile

TB-500 has a favorable safety profile in preclinical research. It is a fragment of an endogenous human protein, and no organ toxicity, mutagenicity, or significant immune reactions have been documented in animal studies at research doses. Human clinical data is limited, consistent with most research peptides.

Commonly Reported Observations

• Mild injection site reactions — redness, slight tenderness, or a small temporary nodule at the injection site. These are common with any subcutaneous injection and typically resolve within 24 hours. Rotating sites reduces localized tissue irritation.
• Mild fatigue or tiredness on injection days, particularly during the loading phase. This typically resolves after the first 1–2 weeks as the body adapts.
• Some users report a mild "head rush" or brief dizziness immediately after injection, likely related to transient hemodynamic changes from the vasodilatory activity. Lying down briefly after injection prevents this.
• Temporary flu-like symptoms (mild body ache, lethargy) during the first week of a new protocol are occasionally reported. These are self-limiting and resolve without intervention.

Theoretical Concerns

• Angiogenesis in malignant contexts: TB-500's potent angiogenic activity is beneficial for tissue repair but could theoretically support tumor vascularization in individuals with active cancer. Use in the context of active malignancy is contraindicated without oncological oversight.
• Long-term use data: The longest available preclinical studies span several months. Human data for cycles beyond 12 weeks is anecdotal. Cycling protocols with breaks are recommended as a precaution.

Contraindications

• Active cancer or history of malignancy (without medical supervision)
• Pregnancy and breastfeeding (insufficient safety data)
• Known hypersensitivity to TB-500 or its excipients

Combinations and Stacks

TB-500 + BPC-157 — The Healing Stack

The combination of TB-500 with BPC-157 is the premier tissue-repair stack in peptide research, often called the Healing Stack. The two peptides work through distinct pathways that create a powerful synergy:

• TB-500 drives cell migration, angiogenesis at the endothelial level, and systemic anti-apoptotic signaling, mobilizing repair resources from the circulation and from bone marrow.
• BPC-157 drives local angiogenesis through the NO pathway, upregulates growth hormone receptors on fibroblasts, and provides potent gastrointestinal and neurological cytoprotection.
• Together, they address tissue repair at both the systemic (TB-500) and local (BPC-157) level, covering the full arc from initial cell recruitment through structural remodeling to final collagen maturation.

Healing Stack protocol: TB-500 2.5 mg, 2–3x per week + BPC-157 250–500 mcg daily, both subcutaneous, for 4–8 weeks. View the BPC-157 calculator for BPC-157 dosing details.

TB-500 + GHK-Cu

For comprehensive soft tissue and skin repair — particularly relevant after surgery, burns, or chronic wounds — combining TB-500 with GHK-Cu adds the copper peptide's collagen synthesis stimulation and antioxidant gene modulation to TB-500's cell migration and vascular effects. This combination is particularly suited to users with skin or hair restoration goals alongside systemic tissue repair objectives.

TB-500 as a Standalone for Cardiac and Neural Recovery

TB-500 has the most extensive evidence base for cardiac tissue repair of any peptide in research. Studies in myocardial infarction models demonstrate that TB-500 significantly reduces infarct size, improves ventricular function, promotes cardiomyocyte survival, and stimulates new vessel formation in ischemic zones. For neural recovery applications, preclinical evidence shows improved outcomes after traumatic brain injury and peripheral nerve crush models. These are among the most compelling potential applications for TB-500 and the primary reason it attracts interest beyond musculoskeletal use.

You can purchase research-grade TB-500 from BergdorfBio: TB-500 at BergdorfBio.

Frequently Asked Questions

How is TB-500 different from full-length Thymosin Beta-4?

TB-500 is a 17-amino-acid fragment corresponding to the actin-binding domain of full-length Thymosin Beta-4 (a 43-amino-acid protein). Research has shown that this fragment retains the majority of the parent molecule's biological activity, particularly for wound healing and angiogenesis. TB-500 is more economically synthesizable and has better characterized pharmacokinetics, making it the preferred form for research applications. The two should not be considered identical, however — full-length Tβ4 has additional signaling properties beyond the actin-binding domain.

Why is TB-500 dosed much higher than peptides like BPC-157?

TB-500 operates through mechanisms that require a higher tissue concentration to achieve threshold biological activity. Its actin-sequestration function involves stoichiometric binding to actin monomers — a high-abundance cellular target that demands correspondingly higher peptide concentrations. BPC-157, by contrast, acts through receptor-mediated signaling cascades where even nanomolar concentrations can trigger substantial cellular responses.

How long does TB-500 stay active after injection?

TB-500 has a half-life of approximately 7 days in the body, significantly longer than most research peptides. This extended activity window explains why 2–3 injections per week — rather than daily dosing — are sufficient for therapeutic tissue concentrations. After the last injection in a cycle, biologically active concentrations persist for 1–2 weeks as the peptide slowly clears.

Can TB-500 help with hair loss?

Preclinical evidence is supportive. Thymosin Beta-4 is expressed in hair follicle outer root sheath cells and has been shown to activate hair follicle stem cells, promote anagen (growth phase) maintenance, and stimulate hair shaft elongation in animal models. The relevance to human androgenic alopecia or telogen effluvium has not been established in clinical trials. Some users report improved hair density and reduced shedding after TB-500 cycles, but individual results vary considerably.

Does TB-500 cause weight gain or affect body composition?

No direct anabolic (muscle-building) or lipolytic (fat-burning) activity has been attributed to TB-500. It does not stimulate GH or IGF-1 production. Any improvements in body composition observed during TB-500 use are typically secondary effects of faster injury recovery enabling more consistent training, rather than a direct pharmacological action on muscle or fat tissue.

Is TB-500 detectable in sports drug testing?

TB-500 is prohibited under WADA regulations as a peptide hormone and growth factor. Detection methods exist in anti-doping laboratories and have been validated to identify TB-500 use. Athletes subject to WADA-compliant testing should treat TB-500 as a prohibited substance at all times, including during the off-season.

Can TB-500 be used long-term continuously?

Long-term continuous use is not recommended given the absence of chronic human safety data. Most practitioners use cycle lengths of 8–12 weeks with 4-week breaks. Continuous use beyond 3 months is not well characterized in any published research, and the long half-life means that concentrations accumulate over repeated dosing — making off-periods particularly important for TB-500 relative to shorter-lived peptides.

What size syringe do I need for TB-500?

Because standard TB-500 doses at 2.5 mg/mL concentration require 1.0 mL of solution per injection, a 1.0 mL (100-unit) insulin syringe is the appropriate size. A 0.3 mL or 0.5 mL syringe is not practical at the standard dose because it cannot hold the full injection volume. A 27–29 gauge, 12 mm needle is suitable for subcutaneous injection at this volume.

Medical Disclaimer: The information on this page is provided for educational and research purposes only. TB-500 is not an approved drug or medical treatment and is sold strictly for research use. Nothing on this page constitutes medical advice, diagnosis, or a recommendation to use any specific compound. Always consult a qualified healthcare professional before beginning any peptide protocol. BergdorfBio assumes no liability for the use or misuse of the information presented here.