TB-500
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TB-500 from $84/kit
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Key Facts: TB-500
- Category
- Healing
- FDA Status
- Not FDA Approved
- Clinical Status
- Preclinical - No human clinical trials. FDA Category 2 (pending reclassification to Category 1 per April 15, 2026 HHS announcement; remains Category 2 under current law until formal FDA rule; PCAC review July 23-24, 2026)
- 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
- Duration
- 4-6 weeks loading, then maintenance
Mechanism of Action
Thymosin beta-4 works by grabbing onto G-actin, the building-block form of actin, and acting as the main reservoir cells use to remodel their cytoskeleton. That control over actin lets cells migrate into wounds, which is the proposed basis for faster tissue repair. The active heptapeptide sequence LKKTETQ is the piece that does the actin binding, and TB-500 is built around it. Beyond cell movement, thymosin beta-4 has shown anti-inflammatory effects and pro-angiogenic activity in lab models. Keep in mind that injecting a short synthetic fragment is not guaranteed to reproduce everything the full protein does, so the mechanism story is borrowed largely from research on the parent molecule.
Research Summary
The strongest evidence is preclinical and is mostly about full-length thymosin beta-4, not the TB-500 fragment. Animal studies consistently show accelerated wound healing, reduced scarring, and improved recovery in tendon, skin, and cardiac injury models. On the human side, the biotech company RegeneRx ran the molecule (as RGN-259 eye drops and RGN-352 injection) through actual clinical trials: a placebo-controlled Phase 3 study of RGN-259 in neurotrophic keratopathy reported corneal healing in 6 of 10 treated patients versus 1 of 8 on placebo, and an injectable cardiac program reached Phase 2 before a manufacturing hold. But those programs used full-length thymosin beta-4, not the 7-amino-acid TB-500 fragment sold for research. For the fragment specifically, there are no completed, published human efficacy trials for muscle or tendon repair, and a recently listed cardiovascular biomarker study is early-stage. So: real animal data, real human data for the parent protein, and a near-total gap for TB-500 as sold.
Dosing Information
Note: Animal study doses may not translate directly to humans.
Typical Dosingⓘ
Community experience
2-2.5 mg twice weekly (loading), then 2.5 mg once weekly (maintenance)
2-10 mg per week during loading phase
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ⓘ
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
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9820614/
- https://www.nature.com/articles/s41598-018-28861-5
- https://clinicaltrials.gov/study/NCT07487363
- https://www.regenerx.com/RGN-352
Research This Peptide Further
Buy in shop
TB-500 from $84/kit
4 verified vendors, ≥99% purity, COAs included.
Frequently Asked Questions
What does TB-500 do?
TB-500 is a synthetic peptide that copies the active region of thymosin beta-4, a natural protein that controls how cells build and move their internal skeleton. Most TB-500 products reproduce the short LKKTETQ sequence (residues 17 to 23) responsible for binding actin and driving cell migration, which is why it gets marketed for tendon, muscle, and wound repair. Here is the honest part: there are essentially no completed human trials of the TB-500 fragment itself, and almost all the human clinical data is for the full-length thymosin beta-4 molecule, which is related but not the same thing.
How does TB-500 work?
Thymosin beta-4 works by grabbing onto G-actin, the building-block form of actin, and acting as the main reservoir cells use to remodel their cytoskeleton. That control over actin lets cells migrate into wounds, which is the proposed basis for faster tissue repair. The active heptapeptide sequence LKKTETQ is the piece that does the actin binding, and TB-500 is built around it. Beyond cell movement, thymosin beta-4 has shown anti-inflammatory effects and pro-angiogenic activity in lab models. Keep in mind that injecting a short synthetic fragment is not guaranteed to reproduce everything the full protein does, so the mechanism story is borrowed largely from research on the parent molecule.
Is TB-500 FDA approved?
No, TB-500 is not currently FDA approved. Current status: Preclinical - No human clinical trials. FDA Category 2 (pending reclassification to Category 1 per April 15, 2026 HHS announcement; remains Category 2 under current law until formal FDA rule; PCAC review July 23-24, 2026)
What are the side effects of TB-500?
Reported side effects include: Generally well-tolerated in preclinical studies, Injection site reactions, Headache, Fatigue, Nausea. Individual responses vary based on dosage, duration, and personal health factors.
What is the typical dose of TB-500?
Community-reported common dose: 2-2.5 mg twice weekly (loading), then 2.5 mg once weekly (maintenance) (2x weekly for 4-6 weeks, then 1x weekly). Range: 2-10 mg per week during loading phase. Administration: Subcutaneous or intramuscular injection. Community-reported doses. Not medical advice. Consult healthcare provider.
Related Peptides
Peptides commonly compared with TB-500 or used in similar applications.
BPC-157
PreclinicalBPC-157 is a synthetic 15-amino-acid peptide (sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) based on a fragment of a protective protein found in human gastric juice. It is studied almost entirely in animals for tendon, ligament, gut, and tissue healing, and it has racked up hundreds of preclinical papers. The catch: it is not approved by any regulator for any use, and the human evidence is a handful of small pilot studies, not real clinical proof.
HealingGHK-Cu
Clinical TrialsGHK-Cu is the copper(II) complex of GHK, a naturally occurring human tripeptide (glycyl-L-histidyl-L-lysine) found in blood plasma, saliva and urine, whose levels decline with age. It is researched and widely used in cosmetic skincare for skin regeneration, wound healing, collagen support and anti-aging. It is not an FDA-approved drug; it appears in over-the-counter cosmetics and as a research or compounded peptide, with most human evidence coming from small topical-skincare studies.
Skin & HairThymosin Beta-4
Clinical TrialsThymosin beta-4 (Tbeta4) is a small 43 amino acid peptide found in nearly every cell in the body, originally isolated from the thymus. Its main job is binding and sequestering G-actin, the building block of the cell's internal scaffolding, which lets it influence cell movement, wound repair, and tissue regeneration. It is researched heavily for healing of skin, cornea, and heart tissue, but it is not an FDA-approved drug. (The injectable sold as TB-500 is a synthetic fragment marketed as related to Tbeta4, not the full natural peptide.)
HealingPentadecapeptide
PreclinicalPentadecapeptide almost always means BPC-157, a synthetic 15-amino-acid chain (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) derived from a protein found in human gastric juice. It is one of the most hyped 'healing' peptides online, marketed for tendon, gut, and muscle repair, but here is the catch: essentially all of the supporting evidence is from rats and mice. There is no FDA approval and no completed human clinical trial proving it does any of this.
HealingZiconotide
FDAZiconotide is a real, FDA-approved painkiller pulled from the venom of a marine cone snail. It is not an opioid, and unlike morphine, people do not build tolerance to it over time. The catch: it only works delivered directly into the spinal fluid through an implanted pump, and its side effect profile is rough enough that it carries a black box warning.
HealingGlow Protocol
PreclinicalGLOW (sometimes sold as Glow Blend) is a marketing name for a three-peptide cocktail: GHK-Cu (a copper-binding tripeptide), BPC-157, and TB-500. It is pitched for skin rejuvenation, collagen support, and tissue healing, usually as a single injectable blend from compounding clinics or research suppliers. None of the three peptides is FDA-approved for these uses, and the GLOW combination has never been studied as a product in any clinical trial.
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