A synthetic 17-amino acid fragment of Thymosin Beta-4 (TB-4). Unlike TB-4, TB-500 has a longer half-life (~2-4 days vs ~2 hours) and is the active region responsible for tissue repair and cell migration. Note: Many vendors mislabel TB-4 as 'TB-500' in premixed products.

What are the side effects of TB-500?

Reported side effects of TB-500 include: Generally well-tolerated in preclinical studies, Injection site reactions, Headache, Fatigue, Nausea, May trigger histamine release - use caution with MCAS or histamine sensitivity, Thymosin beta-4 is upregulated in metastatic cancers - theoretical risk of facilitating tumor cell migration, Contraindicated with active cancer or cancer history, Limited long-term safety data, WADA prohibited at all times (2025 list).

What is the typical dosing for TB-500?

Doses observed in research studies. Common doses observed in research: 2-2.5 mg twice weekly, 750 mcg in some protocols. Duration: 4-6 weeks loading, then maintenance. Administration: Subcutaneous or intramuscular injection.

Healing

TB-500

Preclinical

Popular For

Muscle recovery, wound healing, injury rehabilitation

Key Facts: TB-500

Category: Healing
FDA Status: Not FDA Approved
Clinical Status: Preclinical - No human clinical trials, FDA Category 2 (restricted from compounding)
Administration: Subcutaneous or intramuscular injection
Typical Dose: 2-2.5 mg twice weekly (loading), then 2.5 mg once weekly (maintenance)
Frequency: 2x weekly for 4-6 weeks, then 1x weekly
Evidence Level: Animal Studies
Duration: 4-6 weeks loading, then maintenance

Mechanism of Action

TB-500 is derived from the active region of the full Thymosin Beta-4 protein. It promotes cell migration by binding to and sequestering actin, a protein essential for cell movement. It upregulates actin expression, promotes angiogenesis, reduces inflammation, and facilitates hair follicle stem cell migration for wound healing.

Research Summary

Animal studies show significant wound healing acceleration, cardiac tissue repair, and anti-inflammatory effects. Note: Phase 2 human trials exist for full Thymosin Beta-4 protein (not TB-500 specifically) - 73-patient venous stasis ulcer trial showed ~25% achieved complete healing at 3 months. Ophthalmologic trials for dry eye also completed. However, TB-500 fragment itself has no human clinical trials. FDA restricted TB-500 from compounding under Category 2. WADA prohibited at all times.

Clinical Status:Preclinical - No human clinical trials, FDA Category 2 (restricted from compounding)

Trial Progress:Preclinical

Pre

III

FDA

Dosing Information

Animal Studies·Animal studies for TB-500; human trials only on parent Thymosin Beta-4 protein

Note: Animal study doses may not translate directly to humans.

Typical DosingⓘDoses commonly used by people in practice, based on community reports and anecdotal experience.

Community experience

Common Dose

2-2.5 mg twice weekly (loading), then 2.5 mg once weekly (maintenance)

Range

2-10 mg per week during loading phase

Frequency

2x weekly for 4-6 weeks, then 1x weekly

Loading phase builds up tissue levels. Maintenance phase sustains benefits. Often stacked with BPC-157 for injury recovery.

Research DosingⓘDoses from published scientific studies and clinical trials. May include human or animal research.

Scientific studies

Doses observed in research studies

Doses from Studies

2-2.5 mg twice weekly

Preclinical Research - Animal studies on Thymosin Beta-4 wound healing ↗

750 mcg in some protocols

Preclinical Research - Animal studies on tissue repair mechanisms ↗

Duration

4-6 weeks loading, then maintenance

Administration

Subcutaneous or intramuscular injection

Timing & Administration

Best Time to Take

Morning or evening

2-3 times per week

Food Recommendation

With or without food

Why This Timing?

TB-500 has a long half-life, so timing is flexible. Consistency matters more than specific time of day.

Possible Side Effects

Not everyone experiences these effects. Individual responses vary based on dosage, duration, and personal factors.

●Generally well-tolerated in preclinical studies
●Injection site reactions
●Headache
●Fatigue
●Nausea
●May trigger histamine release - use caution with MCAS or histamine sensitivity
●Thymosin beta-4 is upregulated in metastatic cancers - theoretical risk of facilitating tumor cell migration
●Contraindicated with active cancer or cancer history
●Limited long-term safety data
●WADA prohibited at all times (2025 list)

References

Related Peptides

Peptides commonly compared with TB-500 or used in similar applications.

BPC-157

Preclinical

A synthetic peptide derived from a protein found in human gastric juice. Known for its remarkable tissue healing properties across multiple body systems. FDA classified as Category 2 in 2023, restricting compounding.

Healing

GHK-Cu

Clinical Trials

A naturally occurring copper-binding peptide found in human plasma, saliva, and urine. Widely used in skincare for its wound healing and anti-aging properties.

Skin & Hair

Thymosin Beta-4

Clinical Trials

The full 43-amino acid protein that TB-500 is derived from. Naturally occurring in most human tissues, TB-4 has a shorter half-life (~2 hours) compared to its synthetic fragment TB-500 (~2-4 days). Often mislabeled as 'TB-500' by vendors in premixed products.

Healing

Pentadecapeptide

Preclinical

The full 15-amino acid sequence that includes BPC-157. While BPC-157 is more commonly discussed, the full pentadecapeptide has similar healing properties derived from gastric juice.

Healing

Ziconotide

FDA

A synthetic cone snail venom peptide for severe chronic pain. The first intrathecal non-opioid analgesic FDA approved.

Healing

LL-37

Clinical Trials

A naturally occurring antimicrobial peptide and the only human cathelicidin. Part of the innate immune system with broad-spectrum antimicrobial activity.

Immune

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