TB-500
Also called Ac-LKKTETQ, thymosin beta-4 fragment, tb500, TB4 fragment
The systemic healer
TB-500 is a short synthetic fragment of thymosin beta-4, a protein your body makes that helps cells move to damaged tissue. It is used for tendon, muscle and joint injuries. The human trials that exist used the full protein for dry eye and leg ulcers, not the fragment for sports injuries.
TB-500 is a short seven-amino-acid fragment copied from the middle of a much larger protein your body makes called thymosin beta-4. That protein is 43 amino acids long and helps cells travel to the site of an injury; TB-500 is the small piece of it thought to do that job. Worth knowing before you buy: some suppliers sell the whole 43-amino-acid protein under the same TB-500 name, and the two are different molecules with different weights, so an identical label on two vials can mean quite different things.
- Route
- Subcutaneous
- Typical dose
- 2–5 mg 2x/week
- Availability
- Research-only
Human trials published, with more underway
1,045 papers · 8 clinical trials
What people use TB-500 for
Reported uses, roughly in order of how often they are the reason someone goes looking. Whether it works for any of them is a separate question, answered under each one.
- Wound healing
- Where the human evidence actually is, using the full protein on venous leg ulcers.
- Dry eye
- The other place it has been properly trialled, as an eye drop in a Phase 2 study.
Mechanism of Action
How TB-500 works
For a cell to reach an injury, it has to crawl. Cells move by building an internal scaffold at the front, pulling themselves forward, then dismantling it behind and rebuilding it further on. The scaffold is made of a protein called actin, and the crawl only works if there is a ready supply of loose actin to build with.
Thymosin beta-4 is the protein that manages that supply. It holds loose actin in reserve and releases it where building is needed, so cells can migrate toward damage rather than sitting still.
TB-500 is a short piece cut out of that protein, the part thought to do the actin holding.
The distinction that changes how you read everything
A fragment is not the protein. TB-500 is seven amino acids; thymosin beta-4 is 43. They are related the way a sentence is related to a paragraph it was taken from.
This matters because the human studies people cite used the full protein, not the fragment. And they tested severe dry eye and venous leg ulcers, using eye drops and topical treatment.
So the safety data is genuinely reassuring about a 43-amino-acid protein given to healthy volunteers, and it says very little about injecting a seven-amino-acid fragment for a torn tendon. That is the use it is overwhelmingly sold for, and it is the one use nobody has trialled in people.
Why it is paired with BPC-157
The reasoning is that one works where you inject it and the other travels. It is a tidy story. No study has tested the two together in animals or people.
TB-500 dosage calculator
Opens at 2 mg, from the doses reported for TB-500. Change any box to match your own vial. It works out where to pull the plunger to.
How much is in the vial?
Printed on the label, in milligrams
How much water did you add?
Bacteriostatic water, in millilitres
What dose are you taking?
The dose you already intend to use
Which syringe?
Barrel size, printed on the wrapper
Draw to
40 units
on a 0.5 mL insulin syringe (0.4 mL)
- Strength once mixed
- 5 mg/mL
- Doses in the vial
- 5
10 mg in 2 mL makes 5 mg/mL. A 2 mg dose is 0.4 mL of that, which is 40 units.
Want a rounder number? Adding 0.5 mL instead would put this dose at exactly 10 units, which is easier to draw accurately.
This is arithmetic, not advice. It converts a dose you already have into a mark on a syringe. It does not tell you what dose to take, and TB-500 is not prescribed by us. Dosing belongs with a qualified clinician.
TB-500 side effects: what people reported
Quiet, and reported as such consistently. Because it stays in tissue for days rather than hours, people describe a slower onset of anything they do notice.
What people report
- Injection-site soreness or redness
- A head rush shortly after a dose
- Tiredness or a heavy-limbed feeling in the first days, which people usually describe as the body doing repair work
- Mild nausea
Worth keeping an eye on
- It promotes new blood vessel growth, which is the mechanism, so a cancer history is a conversation for an oncologist
- Reactions that worsen over a day rather than settle, which points at the vial rather than the compound
Source: Reported use; there is no large human trial to build a formal table from. This is a summary of published findings, not a complete safety profile and not medical advice. TB-500 should only be considered with a qualified clinician who knows your history.
Your Genetics & TB-500
The genes involved in how TB-500 works
TB-500 works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
MMP3 · ••
The 5A/6A promoter polymorphism affects MMP3 expression levels. The 5A allele increases matrix breakdown speed — TB-500's MMP modulation may be more critical for 5A carriers to prevent excessive tissue degradation.
Fibronectin is essential for cell migration and wound healing scaffolding. Variants affecting FN1 expression alter the extracellular matrix environment that TB-500 works within, potentially changing migration efficiency.
VEGFA · ••
Affects baseline VEGF-A production, which drives new blood vessel formation. TB-500 promotes angiogenesis — carriers with lower baseline VEGF may see proportionally greater benefit from this pathway.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which variants do you carry?
Upload your DNA data, or get tested through our partner, to find out.
Commonly combined with
What TB-500 is most often paired with, and why:
BPC-157
Wolverine StackModerate EvidenceBody Protection Compound 157
BPC-157 is the peptide people reach for when something will not heal. Tendons, ligaments, a gut that has been irritated by painkillers, an injury that has stalled. It is a short chain of amino acids copied from part of a protein your stomach already makes, and the animal research on it is unusually consistent for this category: across a lot of separate rat studies, injured tissue healed faster than it did without it. The gap is that this has largely not been repeated in people, and it is not an approved medicine, so nobody is checking what is in the vial you buy.
3
Gene variants
19+
Studies
GHK-Cu
Full Regeneration StackModerate EvidenceGlycyl-L-Histidyl-L-Lysine Copper Complex
A naturally occurring copper-binding tripeptide, studied mainly for wound healing and skin. It carries copper into tissue, where copper is the cofactor the enzyme that cross-links collagen cannot work without. Most of the evidence is topical or in rats; the widely quoted gene-expression claims rest on far less than they appear to.
CJC-1295
Recovery StackModerate EvidenceCJC-1295 (Modified GRF 1-29)
A copy of the brain signal that tells the pituitary to release growth hormone, rewritten so the enzyme that normally destroys it in minutes cannot. Before you read any dose, check which version you have: with DAC it keeps growth hormone up for days, without DAC it produces a short pulse, and nearly every blend sold with ipamorelin contains the second one.
4
Gene variants
30+
Studies
Common Stacks
One of these pairings has a name people search for, and a page of its own.
Skin and appearance
KLOW
80 mg vialGLOW with an anti-inflammatory peptide added
Skin and appearance
GLOW
70 mg vialThe skin blend: one collagen peptide and two repair peptides
Healing and repair
Wolverine Stack
10 mg vialThe two repair peptides people pair for injuries
Sourcing & access
Where to buy TB-500
TB-500 is sold as a research compound, not a licensed medicine, so quality and legal status vary widely by country and vendor. If you're sourcing it, treat independent purity testing as non-negotiable.
- Insist on a recent third-party Certificate of Analysis (COA) for the exact batch — labs like Janoshik verify purity and identity.
- Check the legal status where you live before ordering — it differs from country to country.
- Reconstitute correctly with bacteriostatic water and start at a conservative dose.
Before you buy: see whether your DNA actually responds to TB-500, and at what dose. Analyze my DNA — $99 →
Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you). Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Worth knowing before you consider TB-500
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- The fragment is not the molecule that was trialled
- Every human result here used full thymosin beta-4. TB-500 is a short piece of it, chosen because it is cheaper to make and contains the part thought to bind actin. Whether the fragment does everything the protein does has not been established in people.
- No human trial exists for the use it is sold for
- Tendon, ligament and muscle repair is the entire marketing case, and it rests on rat studies. That is not the same as evidence of no effect, but it is a long way from the dry-eye and ulcer trials being cited as if they transfer.
- Banned in sport, and a caution about actively growing tumours
- It is prohibited under WADA rules at all times. Because thymosin beta-4 promotes new blood vessel growth and cell migration, which is how it helps tissue heal, it is a mechanism worth discussing with an oncologist if cancer is in the picture.
The evidence behind TB-500
Two distinctions decide how to read everything below. First, TB-500 is a seven-amino-acid fragment; the trials used full thymosin beta-4, a 43-amino-acid protein. They are related but not the same thing. Second, the human trials tested eye drops for dry eye and topical treatment for leg ulcers. Nobody has run a human trial of either molecule for the tendon and muscle injuries this is sold for, so the safety data below is genuinely reassuring about the protein and tells you little about injecting the fragment.
The literature, counted
Counted in PubMed on 3 August 2026 for thymosin beta 4 OR TB-500. Every figure links to the search that produced it, so you can re-run it. “Tagged human” is not the same as a human trial: that tag also covers work on human cells and reviews discussing people, which is why the trial count is given separately.
Studied in people
3 of 4The only kind that directly answers whether it works in humans.Cornea · 2015
HumanThymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial
Sosne G, Dunn SP, Kim C
The clearest positive human result for thymosin beta-4: a randomised trial in severe dry eye reporting improvement in both signs and symptoms. It was an eye drop, using the full protein.
Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial — source for TB-500 (opens in a new tab)Phase 2
Read the paperAnnals of the New York Academy of Sciences · 2010
HumanA randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers
Ruff D, Crockford D, Girardi G, Zhang Y
The human safety study, giving thymosin beta-4 intravenously to healthy volunteers in single and repeated doses against placebo. This is the source of the claim that it is well tolerated, and it is worth knowing it tested the protein rather than TB-500.
A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers — source for TB-500 (opens in a new tab)Read the paperAnnals of the New York Academy of Sciences · 2007
HumanThymosin beta-4 and venous ulcers: clinical remarks on a European prospective, randomized study on wound healing
Guarnera G, De Rosa A, Camerini R
A European randomised study in venous leg ulcers, the other place the protein has been properly tested in people. Wound healing, not sports injury.
Thymosin beta-4 and venous ulcers: clinical remarks on a European prospective, randomized study on wound healing — source for TB-500 (opens in a new tab)Read the paper
Every source behind this page63 more
- A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of thymosin β4Wang X, Liu L, Qi L, et al. · Journal of Cellular and Molecular Medicine · 2021 · Phase 1Human
- Thymosin beta4: actin-sequestering protein moonlights to repair injured tissuesGoldstein AL, Hannappel E, Kleinman HK · Trends in Molecular Medicine · 2005Review
- Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine PhysiciansMayfield CK, Bolia IK, Feingold CL, et al. · American Journal of Sports Medicine · 2026Review
Everything we cite for TB-500, including animal work and early research. Each link goes to the source itself, so you can judge it rather than take our word for it.
Last updated · literature counts verified against PubMed on
Frequently Asked Questions
What is TB-500 used for?
TB-500 is used for systemic tissue repair — it travels through the bloodstream to reach injuries throughout the body, unlike localized treatments. It's popular for tendon and ligament injuries, post-surgical recovery, cardiac repair, and chronic inflammatory conditions. It works by promoting cell migration and actin dynamics.
How is TB-500 different from BPC-157?
BPC-157 works locally through nitric oxide and angiogenesis, best for targeted injuries (tendons, gut). TB-500 works systemically through actin regulation, reaching all injury sites simultaneously. Together they form the 'Wolverine Stack' — localized precision plus systemic reach for comprehensive healing.
Does genetics affect TB-500 response?
Yes. MMP3 variants affect your tissue remodeling speed, which TB-500 modulates. FN1 variants influence the cell migration scaffold TB-500 depends on, and VEGFA variants shape the angiogenesis TB-500 promotes. A genetic peptide report identifies these factors before starting a protocol.
Learn more about TB-500
32 guides mention TB-500→stacking
In depthThe Wolverine Stack: BPC-157 + TB-500 Complete Guide
16 min read
stacking
Peptide Stacking 101: The Rules, the Risks, and the Science
13 min read
stacking
How to Build a Peptide Stack: A DNA-Guided Approach
13 min read
comparisons
In depthBPC-157 vs TB-500 for Muscle Injury: Which One Rebuilds Faster?
12 min read
safety
In depthTB-500 and BPC-157 Half-Life: How Long They Stay in Your System
12 min read
peptide guides
In depthTB-500 Dosage Guide: Exact Protocol by Injury Type (Not Just a Chart)
13 min read
Your next move
Two ways forward with TB-500.
Not sure it's for you?
How does TB-500 relate to your genes?
Your report scores TB-500 against your receptor, pharmacogene and pathway variants and shows the genetic markers relevant to it, with commonly cited dosing information to review with a clinician.
Analyze my DNA — $99Already decided?
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