What's the difference between Thymosin Beta-4 and TB-500?

TB-500 is a synthetic fragment containing the active region (amino acids 17-23, sequence LKKTETQ) of Thymosin Beta-4, often presented as a 43-44 amino acid peptide that's slightly modified from the natural sequence. Full Thymosin Beta-4 is the complete, naturally occurring 43-amino acid protein. The distinction matters: TB-500 is designed to capture the core actin-binding and cell-migration promoting activity, but the full protein may have additional functions from its other regions. TB-500 is more common in research peptide markets because it's easier to synthesize; pharmaceutical-grade Thymosin Beta-4 has been used in clinical trials. In practice, many people use 'TB-500' and 'Thymosin Beta-4' interchangeably, though technically they're different molecules with overlapping activity.

How does Thymosin Beta-4 actually promote healing?

Multiple mechanisms work together. First, it regulates actin dynamics—by binding G-actin monomers, it controls the polymerization of actin filaments that cells need for migration and shape change. This allows repair cells like keratinocytes, fibroblasts, and endothelial cells to move efficiently into wounded areas. Second, it's powerfully anti-inflammatory, reducing pro-inflammatory cytokines while promoting resolution of inflammation. Third, it stimulates angiogenesis—new blood vessels bring oxygen and nutrients essential for tissue rebuilding. Fourth, it appears to activate stem and progenitor cells in various tissues. Fifth, it protects cells from apoptosis (programmed death) under stress conditions. This multi-target approach explains why it seems effective across diverse injury types—it's not treating one pathway, it's facilitating the body's entire healing cascade.

Is Thymosin Beta-4 the same as Thymosin Alpha-1?

No, they're completely different proteins with different functions, despite similar names. Both were originally isolated from the thymus, which is how they got grouped together as 'thymosins.' Thymosin Alpha-1 is a 28-amino acid peptide primarily involved in immune modulation—it enhances T-cell function and is used clinically for hepatitis B and as an immune adjuvant. Thymosin Beta-4 is a 43-amino acid protein focused on tissue repair, cell migration, and wound healing. They don't share sequence homology or functions. The naming is historical and confusing—treat them as unrelated molecules that happen to have similar names.

What clinical trials have been conducted with Thymosin Beta-4?

RegeneRx Biopharmaceuticals has led most clinical development. RGN-259, a topical formulation, has completed Phase 2 trials for dry eye syndrome and neurotrophic keratitis (corneal nerve damage), showing improved healing and symptom reduction. RGN-352, an injectable form, completed early-phase trials for acute myocardial infarction, exploring whether administration after heart attacks could reduce damage and improve cardiac function. Results were promising enough to continue development but not yet conclusive. The company has also explored wound healing applications. Progress has been slower than the preclinical data suggested, partly due to funding and development challenges typical for smaller biotech firms. Clinical-grade Thymosin Beta-4 remains investigational, not approved for general medical use.

Why do athletes and bodybuilders use TB-500/Thymosin Beta-4?

The healing and recovery properties make it attractive for sports injuries. Users report faster recovery from muscle strains, tendinitis, and ligament injuries. The anti-inflammatory effects may reduce pain and swelling. Some believe it helps with flexibility and reduces adhesions after injury. Whether these reports reflect genuine enhanced healing or placebo effect remains unclear—controlled trials in athletes haven't been conducted. TB-500 and Thymosin Beta-4 are banned by WADA (World Anti-Doping Agency) under the category of growth factors, so competitive athletes can't legally use them. The research peptide market supplies people willing to self-experiment, but quality control and actual clinical outcomes are highly variable.

Can Thymosin Beta-4 regrow hair?

There's intriguing research but don't expect miracles. Studies in mice showed Thymosin Beta-4 promotes hair follicle stem cell migration and accelerates hair growth. The mechanism involves activating follicle stem cells and promoting the transition from resting (telogen) to growth (anagen) phase. Human data is much more limited. Some users of TB-500 report improved hair quality or regrowth, but these are anecdotal reports subject to confirmation bias. No clinical trials have specifically evaluated hair regrowth in humans. If Thymosin Beta-4 does help with hair, it's likely as one component of a multi-factor approach rather than a standalone solution. The regenerative and stem cell-activating properties provide biological plausibility, but definitive evidence in humans is lacking.

Is Thymosin Beta-4 safe?

Clinical trials have shown a favorable safety profile at studied doses, with no serious adverse events directly attributed to the drug. Since Thymosin Beta-4 is a naturally occurring protein abundant in human cells, the body recognizes it. That said, enhancing tissue repair and cell proliferation raises theoretical concerns about cancer—if you accelerate cell growth, could you accelerate tumor growth? Preclinical studies haven't shown increased cancer risk, and some suggest Thymosin Beta-4 might actually suppress tumor invasiveness, but this remains an area of ongoing research. Short-term use for injury healing appears reasonably safe based on available data. Long-term effects of chronic supplementation are unknown. Research peptide market products carry additional risks from purity, contamination, and dosing accuracy that pharmaceutical-grade material would not have.

Homechevron_rightPeptideschevron_rightThymosin Beta-4

Regenerative

scheduleHalf-life: Research estimates suggest relatively rapid clearance; TB-500 fragment has ~2-3 hour half-life

Thymosin Beta-4

Thymosin Beta-4 (Tβ4)

Thymosin Beta-4 is one of the most abundant proteins in human cells, and for good reason—it's a master regulator of healing. This 43-amino acid protein was originally isolated from the thymus but is actually produced throughout the body wherever tissue repair is needed. Its primary function is managing actin, the protein that forms cellular scaffolding and enables cells to move. By sequestering G-actin (the building block form), Thymosin Beta-4 controls how and when cells reorganize their structure for migration, division, and wound closure. Beyond actin regulation, it reduces inflammation, promotes blood vessel formation (angiogenesis), protects cells from death signals, and appears to activate stem cells. The research peptide TB-500 is derived from Thymosin Beta-4's active region, but the full molecule contains additional sequences that may contribute to its regenerative effects. In clinical trials, Thymosin Beta-4 has shown promise for wound healing, corneal injuries, and cardiac repair after heart attacks. It represents an emerging understanding that the body's own healing factors might be enhanced therapeutically.

What is Thymosin Beta-4?
Research Benefits
How Thymosin Beta-4 Works
Research Applications

References

What is Thymosin Beta-4?

Research Benefits

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Accelerates wound healing

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Reduces inflammation

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Promotes cell migration and tissue repair

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Supports angiogenesis (new blood vessel formation)

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Protects tissues from hypoxic damage

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May improve cardiac function post-injury

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Promotes hair follicle stem cell activity

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Regulates extracellular matrix remodeling

Research Applications

science

Wound healing and tissue repair

Active research area with published studies

science

Cardiac regeneration post-MI

Active research area with published studies

science

Corneal healing and dry eye

Active research area with published studies

science

Muscle injury recovery

Active research area with published studies

science

Dermal wound closure

Active research area with published studies

science

Neuroregeneration

Active research area with published studies

science

Hair growth stimulation

Active research area with published studies

science

Anti-fibrotic applications

Active research area with published studies

Frequently Asked Questions

Scientific References

Thymosin Beta-4: A Multi-Functional Regenerative Peptide

Annals of the New York Academy of Sciences (2012)

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Thymosin Beta-4 for Treatment of Corneal Wounds

Expert Opinion on Biological Therapy (2018)

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The Role of Thymosin Beta-4 in Cardiac Regeneration

International Journal of Molecular Sciences (2021)

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Quick Reference

Molecular Weight4,921 Da

Half-LifeResearch estimates suggest relatively rapid clearance; TB-500 fragment has ~2-3 hour half-life

Purity≥98% for research applications

FormLyophilized powder | Injectable solution for clinical research

Sequence

Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES (43 amino acids)

Storage

Store lyophilized powder at -20°C | Reconstituted solution at 2-8°C, use within 7-10 days | Avoid repeated freeze-thaw cycles

Related Peptides

Thymosin Beta-4 (Tβ4)

What is Thymosin Beta-4?

Research Benefits

check_circle

Accelerates wound healing

check_circle

Reduces inflammation

check_circle

Promotes cell migration and tissue repair

check_circle

Supports angiogenesis (new blood vessel formation)

check_circle

Protects tissues from hypoxic damage

check_circle

May improve cardiac function post-injury

check_circle

Promotes hair follicle stem cell activity

check_circle

Regulates extracellular matrix remodeling

Research Applications

science

Wound healing and tissue repair

Active research area with published studies

science

Cardiac regeneration post-MI

Active research area with published studies

science

Corneal healing and dry eye

Active research area with published studies

science

Muscle injury recovery

Active research area with published studies

science

Dermal wound closure

Active research area with published studies

science

Neuroregeneration

Active research area with published studies

science

Hair growth stimulation

Active research area with published studies

science

Anti-fibrotic applications

Active research area with published studies

Frequently Asked Questions

Scientific References

Thymosin Beta-4: A Multi-Functional Regenerative Peptide

Annals of the New York Academy of Sciences (2012)

open_in_new

Thymosin Beta-4 for Treatment of Corneal Wounds

Expert Opinion on Biological Therapy (2018)

open_in_new

The Role of Thymosin Beta-4 in Cardiac Regeneration

International Journal of Molecular Sciences (2021)

open_in_new

Thymosin Beta-4

Thymosin Beta-4 (Tβ4)

Table of Contents

What is Thymosin Beta-4?

Research Benefits

Research Applications

Wound healing and tissue repair

Cardiac regeneration post-MI

Corneal healing and dry eye

Muscle injury recovery

Dermal wound closure

Neuroregeneration

Hair growth stimulation

Anti-fibrotic applications

Frequently Asked Questions

What's the difference between Thymosin Beta-4 and TB-500?

How does Thymosin Beta-4 actually promote healing?

Is Thymosin Beta-4 the same as Thymosin Alpha-1?

What clinical trials have been conducted with Thymosin Beta-4?

Why do athletes and bodybuilders use TB-500/Thymosin Beta-4?

Can Thymosin Beta-4 regrow hair?

Is Thymosin Beta-4 safe?

Scientific References

Thymosin Beta-4: A Multi-Functional Regenerative Peptide

Thymosin Beta-4 for Treatment of Corneal Wounds

The Role of Thymosin Beta-4 in Cardiac Regeneration

Quick Reference

Related Peptides

Thymosin Beta-4

Thymosin Beta-4 (Tβ4)

Table of Contents

What is Thymosin Beta-4?

Research Benefits

Research Applications

Wound healing and tissue repair

Cardiac regeneration post-MI

Corneal healing and dry eye

Muscle injury recovery

Dermal wound closure

Neuroregeneration

Hair growth stimulation

Anti-fibrotic applications

Frequently Asked Questions

What's the difference between Thymosin Beta-4 and TB-500?

How does Thymosin Beta-4 actually promote healing?

Is Thymosin Beta-4 the same as Thymosin Alpha-1?

What clinical trials have been conducted with Thymosin Beta-4?

Why do athletes and bodybuilders use TB-500/Thymosin Beta-4?

Can Thymosin Beta-4 regrow hair?

Is Thymosin Beta-4 safe?

Scientific References

Thymosin Beta-4: A Multi-Functional Regenerative Peptide

Thymosin Beta-4 for Treatment of Corneal Wounds

The Role of Thymosin Beta-4 in Cardiac Regeneration

Quick Reference

Related Peptides