Updated April 2026

TB-500 Dosing Protocol

Q: What is the starting dose of TB-500?

A common start is 2-2.5 mg SubQ twice weekly (4-5 mg/week) during loading. Intensive starts may use 1-2 mg daily or every other day in weeks 1-2, then transition to maintenance around 2-4 mg/week.

Q: What is TB-500's half-life?

TB-500's half-life in the bloodstream is short, at under 2 hours based on animal pharmacokinetic (PK) studies. However, the important part is that TB-500's tissue-level effects persist for days to weeks after injection, even after the peptide clears from the blood. This is why twice-weekly dosing is the standard in community protocols rather than daily injections.

Q: What results can be expected from TB-500?

Reports commonly describe improved flexibility and reduced stiffness within 1-2 weeks, with broader recovery trends over 4-8 weeks. Preclinical wound models reported accelerated re-epithelialization and repair metrics.

Q: How do you reconstitute TB-500?

To reconstitute TB-500, draw your measured amount of bacteriostatic water into a syringe, inject it slowly against the inside wall of the vial (not directly onto the powder), then gently roll the vial until dissolved. Don't shake it. Store refrigerated at 2-8°C. A common setup: add 1 mL of water to a 5 mg vial to get a concentration of 5 mg/mL. At that concentration, a 2.5 mg dose equals 0.50 mL, which is 50 units on a standard U-100 insulin syringe. For other vial sizes and custom water volumes, use the PepPal reconstitution calculator.

Q: Is TB-500 FDA-approved?

No. TB-500 is not FDA-approved for any indication. It is generally referenced as a research compound and Category 2 bulk drug substance context, and it is prohibited by WADA under S0 non-approved substances.

Q: What are the most common side effects of TB-500?

Most commonly reported effects are mild and transient: temporary fatigue, headache, mild nausea, lightheadedness, and occasional minor injection-site irritation.

Q: How does TB-500 compare to BPC-157?

TB-500 is usually used for systemic, whole-body repair context and dosed at milligram levels twice weekly, while BPC-157 is commonly used for localized tissue and GI context with daily microgram dosing. They are often combined in the Wolverine Stack.

Q: What vial sizes is TB-500 available in?

Common research vial sizes are 2 mg, 5 mg, and 10 mg lyophilized formats.

Q: How much bacteriostatic water should be added to TB-500?

Common choices are 5 mg + 1 mL (5 mg/mL), 10 mg + 2 mL (5 mg/mL), or 5 mg + 2 mL (2.5 mg/mL), depending on preferred injection volume and unit precision.

Q: What is the maximum dose of TB-500 studied?

A Phase I trial reported IV thymosin beta-4 doses up to 1,260 mg daily for 14 days in healthy adults without dose-limiting toxicity, far above typical community SubQ ranges.

Written by Garret Grant

Founder & Lead Researcher · B.S. Civil Engineering, UCLA

Last updated: April 2026

Complete Dosing & Safety Guide for TB-500, a Systemic Tissue Repair Peptide Frequently Discussed Alongside BPC-157, covering loading and maintenance schedules, reconstitution math, side effects, and clinical evidence.

Half-life

<2 hours plasma; tissue effects persist days to weeks

Dose range

2-5 mg per injection, 4-10 mg weekly

Status

Not FDA-approved

Developer

RegeneRx Biopharmaceuticals (RGN-259 ophthalmic)

Need to calculate reconstitution and dosing units? Use the dose to units converter.

Quick Reference Dosing Card

Peptide Name

TB-500 (Thymosin Beta-4)

Use Case

Research users commonly explore TB-500 for systemic soft-tissue repair and recovery support.

Aliases

Tβ4, TB4, Timbetasin (INN), Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES

Category / Class

Tissue Repair / Actin Sequestration Peptide

Half-Life

<2 hours plasma (animal PK data); biological effects persist days to weeks in tissue

Dosing Frequency

2x per week (SubQ); loading phase may use higher frequency

Dose Range

2-5 mg per injection, 4-10 mg per week (community protocol)

Titration Schedule

Loading: 4-8 mg/week -> maintenance: 2-4 mg/week; intensive loading can reach 5-10 mg/week

Common Vial Sizes

2mg, 5mg, 10mg

Route of Administration

Subcutaneous (SubQ), Intravenous (IV - clinical trials only), Topical (RGN-259 ophthalmic)

Regulatory Status

Not FDA-approved. Research compound. Phase II completed for venous ulcers, dry eye, and epidermolysis bullosa. FDA Category 2 bulk drug substance. Prohibited by WADA under S0.

Developer

RegeneRx Biopharmaceuticals (RGN-259 ophthalmic formulation)

Key Stat

Phase I trial reported IV doses up to 1,260 mg daily for 14 days were well tolerated in 40 healthy adults with no dose-limiting toxicities or serious adverse events.

Peptide Name	TB-500 (Thymosin Beta-4)
Use Case	Research users commonly explore TB-500 for systemic soft-tissue repair and recovery support.
Aliases	Tβ4, TB4, Timbetasin (INN), Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES
Category / Class	Tissue Repair / Actin Sequestration Peptide
Half-Life	<2 hours plasma (animal PK data); biological effects persist days to weeks in tissue
Dosing Frequency	2x per week (SubQ); loading phase may use higher frequency
Dose Range	2-5 mg per injection, 4-10 mg per week (community protocol)
Titration Schedule	Loading: 4-8 mg/week -> maintenance: 2-4 mg/week; intensive loading can reach 5-10 mg/week
Common Vial Sizes	2mg, 5mg, 10mg
Route of Administration	Subcutaneous (SubQ), Intravenous (IV - clinical trials only), Topical (RGN-259 ophthalmic)
Regulatory Status	Not FDA-approved. Research compound. Phase II completed for venous ulcers, dry eye, and epidermolysis bullosa. FDA Category 2 bulk drug substance. Prohibited by WADA under S0.
Developer	RegeneRx Biopharmaceuticals (RGN-259 ophthalmic formulation)
Key Stat	Phase I trial reported IV doses up to 1,260 mg daily for 14 days were well tolerated in 40 healthy adults with no dose-limiting toxicities or serious adverse events.

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What Is TB-500?

TB-500 is a synthetic version of thymosin beta-4 (Tβ4), a naturally occurring 43-amino acid peptide found in virtually all human and animal cells, and is one of the most widely used systemic tissue repair peptides in the research community.

Thymosin beta-4 is found in nearly every cell in the human body and is your body's most abundant repair-signaling protein. It makes up 70-80% of all proteins in its family. Its main job is managing actin, the structural protein that controls whether cells can move to an injury site, divide, and rebuild tissue. This makes thymosin beta-4 fundamental to tissue repair and regeneration across virtually every organ system.

Structurally, thymosin beta-4 consists of 43 amino acids with molecular weight approximately 4,921 daltons. TB-500, the synthetic research version, is distinguished from endogenous Tβ4 by N-terminal acetylation, which enhances stability and biological activity.

TB-500 has progressed further in formal clinical trials than most research peptides. Phase II programs have demonstrated efficacy signals in chronic wound healing and dry eye syndrome (RGN-259), while a landmark Phase I safety study showed extraordinary high-dose tolerability compared with common community SubQ ranges.

This compound is not FDA-approved for any human indication. It is classified as a Category 2 bulk drug substance by the FDA and is prohibited by WADA. All information on this page is for educational and research reference purposes only.

How TB-500 Works: Actin Regulation, Cell Migration & Systemic Tissue Repair

TB-500 works by helping your body's repair cells move to where they're needed and do their job more effectively. Think of it as a logistics coordinator for tissue repair: it clears the path for cells to travel, helps build new blood vessels to supply the area, and calms inflammation so healing can proceed. Here's how each step in the process works.

Mechanism Highlights

Infographic of TB-500 mechanism showing actin regulation, cell migration, angiogenesis signaling, and regenerative pathway effects.

Actin Sequestration & Cytoskeletal Regulation

Every cell has an internal skeleton made of a protein called actin, which controls whether the cell can move, divide, or change shape. TB-500 manages the supply of building blocks (G-actin) for this skeleton, releasing them when cells need to reorganize quickly, like when repair cells need to rush to an injury site. This TB-500 actin sequestration mechanism is the foundation of everything else the peptide does.

Cell Migration & Wound Healing

Once cells can reorganize their internal structure, TB-500 helps them actually get to the wound. It speeds up the migration of skin cells, blood vessel cells, and connective tissue cells to injury sites. In animal wound models, this translated to faster wound closure, better tissue contraction, and more collagen production, which gives repaired tissue its strength.

Angiogenesis & Vascular Repair

Healing tissue needs blood supply, and TB-500 helps build it. It activates several growth-factor pathways (including VEGF and FGF signaling) that promote the formation of new blood vessels, a process called angiogenesis. More blood flow means more oxygen and nutrients reaching the repair site, which supports faster and more complete recovery.

Stem Cell Mobilization & Progenitor Activation

TB-500 doesn't just help existing cells. It can also recruit reinforcements. Published studies in Nature showed that thymosin beta-4 activated dormant progenitor cells (early-stage cells that can develop into specialized tissue) and stimulated new blood vessel growth in heart tissue. This suggests TB-500 can trigger deeper regenerative programs beyond basic wound repair.

Anti-Inflammatory & Anti-Fibrotic Effects

Finally, TB-500 helps manage the inflammation that comes with injury. It reduces inflammatory signaling while organizing how connective tissue repairs itself, limiting the formation of stiff scar tissue (driven by cells called myofibroblasts). The result is tissue that heals more functionally and remains closer to the original tissue rather than a rigid patch.

Together, these five pathways explain why TB-500 is typically treated as a systemic (whole-body) tissue repair peptide rather than a localized treatment. It works wherever your body sends it.

Tools for this Protocol

calculate injection units for reconstitution and units.
Pep Pal calculator to lock in syringe draw volume.

TB-500 Dosing Protocol & Schedule

The TB-500 dosing protocol uses a two-phase approach: a higher-dose "loading" phase in the first few weeks to build up tissue levels, followed by a lower "maintenance" phase to sustain the repair signal. The table below shows two common approaches: standard (for general recovery) and intensive (for acute injury or post-surgical scenarios). Most users follow the standard loading schedule unless directed otherwise.

Loading (standard)

Weeks 1-4 (up to 6)

4-8 mg/week

Typically split into 2 injections per week (2-4 mg each). Higher end is often used for acute or severe injury context.

Maintenance (standard)

Weeks 5-8+

2-4 mg/week

Usually 1-2 injections per week (often 2 mg each) to sustain repair signaling.

Intensive loading

Weeks 1-2

5-10 mg/week

Daily or every-other-day 1-2 mg injections for acute or post-operative scenarios (short-term only).

Standard loading (post-intensive)

Weeks 3-6

4-8 mg/week

Transition to 2x weekly schedule.

Maintenance (extended)

Weeks 7-12

2-4 mg/week

Extend according to recovery assessment.

Cycle guideline (standard)

8-12 weeks total

Loading + maintenance

Common off-period is 4-8 weeks.

Cycle guideline (acute)

4-6 weeks total

Short aggressive loading

Common off-period is 2-4 weeks.

Phase	Weeks	Weekly Dose	Notes
Loading (standard)	Weeks 1-4 (up to 6)	4-8 mg/week	Typically split into 2 injections per week (2-4 mg each). Higher end is often used for acute or severe injury context.
Maintenance (standard)	Weeks 5-8+	2-4 mg/week	Usually 1-2 injections per week (often 2 mg each) to sustain repair signaling.
Intensive loading	Weeks 1-2	5-10 mg/week	Daily or every-other-day 1-2 mg injections for acute or post-operative scenarios (short-term only).
Standard loading (post-intensive)	Weeks 3-6	4-8 mg/week	Transition to 2x weekly schedule.
Maintenance (extended)	Weeks 7-12	2-4 mg/week	Extend according to recovery assessment.
Cycle guideline (standard)	8-12 weeks total	Loading + maintenance	Common off-period is 4-8 weeks.
Cycle guideline (acute)	4-6 weeks total	Short aggressive loading	Common off-period is 2-4 weeks.

Evidence Level Notice & Dosing Notes

Evidence level: Community SubQ dosing is derived from practitioner experience, equine-veterinary use history, and extrapolation from trial data. Optimal SubQ efficacy dosing is not established in large human musculoskeletal trials.

Loading phase rationale: Protocols often use a loading phase to build tissue concentration before reducing to maintenance dosing.

Injection site flexibility: TB-500 is generally treated as systemic regardless of SubQ site; abdomen, thigh, and deltoid are common sites.

Timing and missed dose: No strict time-of-day requirement. If a dose is missed, take the next convenient dose and resume schedule; do not double-dose.

Post-cycle therapy: TB-500 is not known to suppress hormonal axes and does not typically require tapering or PCT.

TB-500 Reconstitution Guide

The table below shows how much bacteriostatic water to add to each common TB-500 vial size and what syringe volume you'll draw for each dose. Find your vial size in the left column, then pick a water volume: less water means a more concentrated solution (smaller injection volumes), while more water makes it easier to measure small doses precisely. "N/A" in a dose column means that dose would require more liquid than the vial contains at that concentration.

Vial Size: 2 mg

BAC Water: 1 mL

Concentration: 2 mg/mL

2 mg: 1.0 mL (100 units)

2.5 mg: N/A

4 mg: N/A

5 mg: N/A

Vial Size: 5 mg

BAC Water: 1 mL

Concentration: 5 mg/mL

2 mg: 0.40 mL (40 units)

2.5 mg: 0.50 mL (50 units)

4 mg: 0.80 mL (80 units)

5 mg: 1.0 mL (100 units)

Vial Size: 5 mg

BAC Water: 2 mL

Concentration: 2.5 mg/mL

2 mg: 0.80 mL (80 units)

2.5 mg: 1.0 mL (100 units)

4 mg: N/A

5 mg: N/A

Vial Size: 10 mg

BAC Water: 2 mL

Concentration: 5 mg/mL

2 mg: 0.40 mL (40 units)

2.5 mg: 0.50 mL (50 units)

4 mg: 0.80 mL (80 units)

5 mg: 1.0 mL (100 units)

Vial Size: 10 mg

BAC Water: 3 mL

Concentration: 3.33 mg/mL

2 mg: 0.60 mL (60 units)

2.5 mg: 0.75 mL (75 units)

4 mg: 1.20 mL (N/A)

5 mg: 1.50 mL (N/A)

Vial Size	BAC Water Added	Concentration	2 mg Dose	2.5 mg Dose	4 mg Dose	5 mg Dose
2 mg	1 mL	2 mg/mL	1.0 mL (100 units)	N/A	N/A	N/A
5 mg	1 mL	5 mg/mL	0.40 mL (40 units)	0.50 mL (50 units)	0.80 mL (80 units)	1.0 mL (100 units)
5 mg	2 mL	2.5 mg/mL	0.80 mL (80 units)	1.0 mL (100 units)	N/A	N/A
10 mg	2 mL	5 mg/mL	0.40 mL (40 units)	0.50 mL (50 units)	0.80 mL (80 units)	1.0 mL (100 units)
10 mg	3 mL	3.33 mg/mL	0.60 mL (60 units)	0.75 mL (75 units)	1.20 mL (N/A)	1.50 mL (N/A)

Step-by-Step Reconstitution Instructions

Step-by-step vial preparation visual showing sterile draw, gentle wall injection, and mixing sequence for peptide reconstitution.

Remove the plastic cap from the TB-500 vial and wipe the stopper with alcohol; allow it to dry.
Draw the planned bacteriostatic water volume using a sterile syringe.
Insert the needle and direct water down the inner glass wall, not directly onto powder.
Allow water to flow gently; do not force or spray liquid into the vial.
Gently roll the vial for 30-60 seconds until dissolved. Do not shake.
Verify the solution is clear and colorless; discard if cloudy, discolored, or particulate.
Store upright refrigerated (2-8C), label with date/concentration, and use within 1-2 weeks.

Need exact syringe units for a custom vial size or BAC water volume? Use the free Peptide Reconstitution Calculator to get instant dose conversions.Open Calculator

TB-500 Side Effects - What Clinical Data Shows

Phase I and Phase II thymosin beta-4 programs reported favorable tolerability, while community SubQ reports usually describe mild, transient symptoms.

Phase I safety data: Randomized placebo-controlled trial in 40 healthy adults reported no dose-limiting toxicities or serious adverse events up to 1,260 mg IV daily for 14 days.

Phase II safety context: Venous ulcer, dry-eye, pressure-ulcer, and epidermolysis-bullosa programs generally described thymosin beta-4 as safe and well tolerated.

Community-reported effects: Most common reports include temporary fatigue, headache, mild nausea, lightheadedness, and occasional mild injection-site irritation.

Theoretical concerns: Because TB-500 supports angiogenic and progenitor-cell pathways, active malignancy is commonly treated as a relative contraindication requiring specialist review.

Hormonal effects: TB-500 does not appear to suppress endocrine axes, does not require post-cycle therapy, and is not associated with withdrawal syndromes in published protocol context.

TB-500 / Thymosin Beta-4 Clinical Trial Results

Ruff et al. 2010 (Ann NY Acad Sci)

Phase I • Single dose + 14 days daily

40 healthy adults

IV 42-1,260 mg was well tolerated with no dose-limiting toxicities or serious adverse events.

Guarnera et al. 2010 (Ann NY Acad Sci)

Phase II • 3 months

73 patients with venous stasis ulcers

0.03% topical Tβ4 improved healing rate; 25% achieved complete healing within 3 months.

Sosne et al. 2015 (Cornea) - RGN-259

Phase II • Multi-site

Severe dry-eye patients

RGN-259 improved corneal staining, tear-breakup time, and symptoms vs placebo.

Bock-Marquette et al. 2004 (Nature)

Preclinical • N/A

Murine cardiac ischemia model

Demonstrated ILK activation with improved cardiac cell migration, survival, and repair.

Smart et al. 2007 (Nature)

Preclinical • N/A

Adult mouse hearts

Showed epicardial progenitor mobilization and neovascularization.

Philp et al. 2004 (FASEB Journal)

Preclinical • 7 days

Rat full-thickness wound model

Re-epithelialization increased 42% at day 4 and 61% at day 7 with improved contraction/collagen trends.

Zhu et al. 2016 (Cytotherapy)

Pilot • N/A

Acute STEMI patients

Tβ4-pretreated endothelial progenitor-cell transplantation showed safety and efficacy signals.

Maar et al. 2021 (Cells)

Preclinical • 6 days systemic

Adult mice

Systemic TB4 increased capsulin-positive progenitors in adult heart structures.

Spurney et al. 2010 (PLoS One)

Preclinical • Chronic administration

mdx mice

Improved skeletal and cardiac muscle function in dystrophin-deficient model.

Gao et al. 2015 (PLoS One)

Preclinical • N/A

Mouse hair-growth model

Demonstrated Tβ4-associated hair follicle and hair-growth effects.

Trial	Phase	Duration	Population	Key Result
Ruff et al. 2010 (Ann NY Acad Sci)	Phase I	Single dose + 14 days daily	40 healthy adults	IV 42-1,260 mg was well tolerated with no dose-limiting toxicities or serious adverse events.
Guarnera et al. 2010 (Ann NY Acad Sci)	Phase II	3 months	73 patients with venous stasis ulcers	0.03% topical Tβ4 improved healing rate; 25% achieved complete healing within 3 months.
Sosne et al. 2015 (Cornea) - RGN-259	Phase II	Multi-site	Severe dry-eye patients	RGN-259 improved corneal staining, tear-breakup time, and symptoms vs placebo.
Bock-Marquette et al. 2004 (Nature)	Preclinical	N/A	Murine cardiac ischemia model	Demonstrated ILK activation with improved cardiac cell migration, survival, and repair.
Smart et al. 2007 (Nature)	Preclinical	N/A	Adult mouse hearts	Showed epicardial progenitor mobilization and neovascularization.
Philp et al. 2004 (FASEB Journal)	Preclinical	7 days	Rat full-thickness wound model	Re-epithelialization increased 42% at day 4 and 61% at day 7 with improved contraction/collagen trends.
Zhu et al. 2016 (Cytotherapy)	Pilot	N/A	Acute STEMI patients	Tβ4-pretreated endothelial progenitor-cell transplantation showed safety and efficacy signals.
Maar et al. 2021 (Cells)	Preclinical	6 days systemic	Adult mice	Systemic TB4 increased capsulin-positive progenitors in adult heart structures.
Spurney et al. 2010 (PLoS One)	Preclinical	Chronic administration	mdx mice	Improved skeletal and cardiac muscle function in dystrophin-deficient model.
Gao et al. 2015 (PLoS One)	Preclinical	N/A	Mouse hair-growth model	Demonstrated Tβ4-associated hair follicle and hair-growth effects.

Clinical evidence chart summarizing TB-500 Phase I safety, Phase II outcomes, and key preclinical study milestones.

Thymosin beta-4 has one of the most developed TB-500 clinical trial programs among tissue-repair peptides. The safety data is especially notable: Phase I testing showed that IV doses up to 1,260 mg daily for 14 days caused no serious side effects in healthy adults. That's roughly 250-600 times higher than typical community subcutaneous doses of 2-5 mg, suggesting a very wide safety margin. Phase II trials showed promising results in healing chronic wounds (venous ulcers) and treating severe dry eye (RGN-259 program). Two landmark Nature publications further support the cardiac repair and stem-cell activation mechanisms that drive current TB-500 research interest. Registered studies include ClinicalTrials.gov NCT00832091, plus additional dry-eye and nerve-related eye-condition programs under the RGN-259 label.

Storage & Handling

Lyophilized (powder)

-20C (freezer)

Long-term (years)

Lyophilized (powder)

2-8C (refrigerator)

Months

Lyophilized (powder)

15-25C (room temp)

Weeks (shipping tolerance)

Reconstituted

2-8C (refrigerator)

1-2 weeks

Reconstituted

Do NOT freeze

N/A - freezing damages reconstituted TB-500

State	Temperature	Duration
Lyophilized (powder)	-20C (freezer)	Long-term (years)
Lyophilized (powder)	2-8C (refrigerator)	Months
Lyophilized (powder)	15-25C (room temp)	Weeks (shipping tolerance)
Reconstituted	2-8C (refrigerator)	1-2 weeks
Reconstituted	Do NOT freeze	N/A - freezing damages reconstituted TB-500

Protect from light and moisture, use bacteriostatic water for multi-dose handling, avoid freeze-thaw cycles, and discard any reconstituted solution that is cloudy, discolored, particulate, or beyond the recommended storage window.

TB-500 vs. BPC-157 vs. GHK-Cu

TB-500, BPC-157, and GHK-Cu are the three most commonly discussed tissue-repair peptides, but they work through different mechanisms and are best suited for different situations. The biggest differences: TB-500 is systemic (works throughout the body) and dosed in milligrams twice weekly; BPC-157 is typically targeted to specific injury areas, dosed in micrograms daily, and can be taken orally; GHK-Cu focuses specifically on collagen and skin quality. Many users combine TB-500 and BPC-157 together in the Wolverine Stack for broader coverage.

Origin

TB-500 (Thymosin Beta-4): Synthetic version of endogenous 43-AA protein

BPC-157: Synthetic 15-AA gastric-protein fragment

GHK-Cu: Naturally occurring tripeptide-copper complex

Primary Mechanism

TB-500 (Thymosin Beta-4): Actin sequestration, migration, progenitor mobilization

BPC-157: VEGF/angiogenesis, NO modulation, cytoprotection

GHK-Cu: Copper-dependent collagen synthesis and remodeling

Half-Life

TB-500 (Thymosin Beta-4): <2 hours plasma; tissue effects persist

BPC-157: <30 minutes

GHK-Cu: ~30 minutes

Route

TB-500 (Thymosin Beta-4): SubQ (2x/week)

BPC-157: SubQ, IM, Oral (1-2x daily)

GHK-Cu: SubQ, Topical

Dose Range

TB-500 (Thymosin Beta-4): 2-5 mg per injection, 2x weekly

BPC-157: 250-500 mcg 1-2x daily

GHK-Cu: 1-2 mg daily (injectable)

Best Use Context

TB-500 (Thymosin Beta-4): Systemic healing, deep tissue, cardiac repair

BPC-157: Localized tendon/ligament/gut repair

GHK-Cu: Skin/wound healing and collagen quality

Oral Viability

TB-500 (Thymosin Beta-4): No

BPC-157: Yes - stable in gastric juice

GHK-Cu: No (topical commonly used)

Clinical Trials

TB-500 (Thymosin Beta-4): Phase I + Phase II

BPC-157: Limited Phase I/II + broad preclinical

GHK-Cu: Phase II skin/wound context

FDA Status

TB-500 (Thymosin Beta-4): Not approved; Category 2 bulk substance

BPC-157: Not approved; Category 2 bulk substance

GHK-Cu: Not approved

Published in Nature

TB-500 (Thymosin Beta-4): Yes - cardiac repair and progenitor studies

BPC-157: No

GHK-Cu: No

Unique Advantage

TB-500 (Thymosin Beta-4): Very wide human safety margin and systemic action

BPC-157: Oral viability with broad tissue-repair use

GHK-Cu: Collagen-focused mechanism

Feature	TB-500 (Thymosin Beta-4)	BPC-157	GHK-Cu
Origin	Synthetic version of endogenous 43-AA protein	Synthetic 15-AA gastric-protein fragment	Naturally occurring tripeptide-copper complex
Primary Mechanism	Actin sequestration, migration, progenitor mobilization	VEGF/angiogenesis, NO modulation, cytoprotection	Copper-dependent collagen synthesis and remodeling
Half-Life	<2 hours plasma; tissue effects persist	<30 minutes	~30 minutes
Route	SubQ (2x/week)	SubQ, IM, Oral (1-2x daily)	SubQ, Topical
Dose Range	2-5 mg per injection, 2x weekly	250-500 mcg 1-2x daily	1-2 mg daily (injectable)
Best Use Context	Systemic healing, deep tissue, cardiac repair	Localized tendon/ligament/gut repair	Skin/wound healing and collagen quality
Oral Viability	No	Yes - stable in gastric juice	No (topical commonly used)
Clinical Trials	Phase I + Phase II	Limited Phase I/II + broad preclinical	Phase II skin/wound context
FDA Status	Not approved; Category 2 bulk substance	Not approved; Category 2 bulk substance	Not approved
Published in Nature	Yes - cardiac repair and progenitor studies	No	No
Unique Advantage	Very wide human safety margin and systemic action	Oral viability with broad tissue-repair use	Collagen-focused mechanism

TB-500 and BPC-157 are commonly combined as the Wolverine Stack, with TB-500 used for systemic repair context and BPC-157 for localized tissue/GI context.

TB-500 is usually dosed less frequently at milligram levels while BPC-157 uses daily microgram dosing.

Reconstitution concentration and unit math differ across compounds and should always be verified before use.

For the full combination model, see /stacks/wolverine-stack.

See the Wolverine Stack Protocol and BPC-157 Protocol for compound-specific guides.

TB-500 Stacking Protocols

Before combining compounds, read the full stacking safety guide on PepPal.

Stack 1

TB-500 + BPC-157 ("Wolverine Stack")

Compounds: TB-500 (2-5 mg twice weekly) plus BPC-157 (250-500 mcg daily).

TB-500 is typically injected SubQ twice weekly at any site, while BPC-157 is usually dosed daily and often placed near target tissue.

This pairing combines systemic actin-regulation and progenitor effects (TB-500) with localized angiogenic/cytoprotective signaling (BPC-157).

See the compound-specific BPC-157 Protocol for additional context.

See full stack protocol

Stack 2

TB-500 + GHK-Cu (Collagen Repair Stack)

Compounds: TB-500 (2-5 mg twice weekly) plus GHK-Cu (1-2 mg daily SubQ or topical).

This stack emphasizes TB-500 systemic migration/healing pathways with GHK-Cu collagen and extracellular-matrix remodeling support.

See full stack protocol

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Frequently Asked Questions - TB-500

Q1: What is the starting dose of TB-500?

A common start is 2-2.5 mg SubQ twice weekly (4-5 mg/week) during loading. Intensive starts may use 1-2 mg daily or every other day in weeks 1-2, then transition to maintenance around 2-4 mg/week.

Q2: What is TB-500's half-life?

TB-500's half-life in the bloodstream is short, at under 2 hours based on animal pharmacokinetic (PK) studies. However, the important part is that TB-500's tissue-level effects persist for days to weeks after injection, even after the peptide clears from the blood. This is why twice-weekly dosing is the standard in community protocols rather than daily injections.

Q3: What results can be expected from TB-500?

Reports commonly describe improved flexibility and reduced stiffness within 1-2 weeks, with broader recovery trends over 4-8 weeks. Preclinical wound models reported accelerated re-epithelialization and repair metrics.

Q4: How do you reconstitute TB-500?

To reconstitute TB-500, draw your measured amount of bacteriostatic water into a syringe, inject it slowly against the inside wall of the vial (not directly onto the powder), then gently roll the vial until dissolved. Don't shake it. Store refrigerated at 2-8°C. A common setup: add 1 mL of water to a 5 mg vial to get a concentration of 5 mg/mL. At that concentration, a 2.5 mg dose equals 0.50 mL, which is 50 units on a standard U-100 insulin syringe. For other vial sizes and custom water volumes, use the PepPal reconstitution calculator.

Q5: Is TB-500 FDA-approved?

No. TB-500 is not FDA-approved for any indication. It is generally referenced as a research compound and Category 2 bulk drug substance context, and it is prohibited by WADA under S0 non-approved substances.

Q6: What are the most common side effects of TB-500?

Most commonly reported effects are mild and transient: temporary fatigue, headache, mild nausea, lightheadedness, and occasional minor injection-site irritation.

Q7: How does TB-500 compare to BPC-157?

TB-500 is usually used for systemic, whole-body repair context and dosed at milligram levels twice weekly, while BPC-157 is commonly used for localized tissue and GI context with daily microgram dosing. They are often combined in the Wolverine Stack.

Q8: What vial sizes is TB-500 available in?

Common research vial sizes are 2 mg, 5 mg, and 10 mg lyophilized formats.

Q9: How much bacteriostatic water should be added to TB-500?

Common choices are 5 mg + 1 mL (5 mg/mL), 10 mg + 2 mL (5 mg/mL), or 5 mg + 2 mL (2.5 mg/mL), depending on preferred injection volume and unit precision.

Q10: What is the maximum dose of TB-500 studied?

A Phase I trial reported IV thymosin beta-4 doses up to 1,260 mg daily for 14 days in healthy adults without dose-limiting toxicity, far above typical community SubQ ranges.

Q11: How should reconstituted TB-500 be stored?

Store reconstituted TB-500 upright at 2-8C and use within 1-2 weeks. Do not freeze reconstituted solution. Lyophilized powder is usually stored frozen for long-term stability.

Q12: What clinical trials have been conducted on Thymosin Beta-4?

Key programs include Phase I IV safety in healthy adults and Phase II studies in venous ulcers and dry eye (RGN-259), plus broad preclinical work including Nature publications on cardiac repair and progenitor mobilization.

Q13: Where can I calculate reconstitution and syringe units?

Use the PepPal calculator for exact dose-to-unit conversions.

Q14: Where can I compare peptide suppliers?

Browse the PepPal supplier directory for current supplier listings.

Sources & Research

Ruff D, Crockford D, Girardi G, Zhang Y. "A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers." Annals of the New York Academy of Sciences, 2010 PubMed.
Bock-Marquette I, et al. "Thymosin β4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair." Nature, 2004.
Smart N, et al. "Thymosin beta4 induces adult epicardial progenitor mobilization and neovascularization." Nature, 2007.
Guarnera G, DeRosa A, Camerini R. "The effect of thymosin treatment of venous ulcers." Annals of the New York Academy of Sciences, 2010.
Sosne G, et al. "Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial." Cornea, 2015.
Philp D, et al. "Thymosin beta4 promotes angiogenesis, wound healing, and hair growth." FASEB Journal, 2004.
Maar K, et al. "Utilizing Developmentally Essential Secreted Peptides Such as Thymosin Beta-4 to Remind the Adult Organs of Their Embryonic State." Cells, 2021 PMC.
Ehrlich HP, Hazard SW. "Thymosin beta4 enhances repair by organizing connective tissue and preventing the appearance of myofibroblasts." Annals of the New York Academy of Sciences, 2010.
Spurney CF, et al. "Evaluation of skeletal and cardiac muscle function after chronic administration of thymosin beta-4 in the dystrophin deficient mouse." PLoS One, 2010.
Zhu J, et al. "Safety and efficacy of autologous thymosin β4 pre-treated endothelial progenitor cell transplantation in patients with acute ST-segment elevation myocardial infarction." Cytotherapy, 2016.
Gao X, et al. "Thymosin Beta-4 Induces Mouse Hair Growth." PLoS One, 2015.
Goldstein AL, et al. "Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications." Expert Opinion on Biological Therapy, 2012.
ClinicalTrials.gov registrations — (NCT00832091).
ClinicalTrials.gov search - RGN-259 dry-eye and neurotrophic keratopathy programs. Search.
Wikipedia - Thymosin beta-4. Link.

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Disclaimer

The information on this page is for educational and research reference purposes only. TB-500 is not FDA-approved for any human indication and is classified as a Category 2 bulk drug substance. It is prohibited by WADA. No compounds discussed on this site are intended for human consumption. This is not medical advice. Consult a qualified healthcare professional before considering any peptide protocol.

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