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Lexicon
Regeneration

TB-500 (Thymosin Beta-4)

A regeneration peptide for tissue, tendons and mobility. Acts systemically rather than locally.

4 min read 12 sources

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Still from the explainer video about this entry
Thymosin beta-4 in phase 3 · not approvedLab tested in the shop

No time to read it all? The video sums up the whole entry in about a minute, from how it works to the studies and storage.

Summary

At a glance

Sources checked on 26 Oct 2026

Thymosin beta-4
43 amino acids

the main peptide that binds free actin in cells2

New skin after 7 days
+61 %

rats with skin wounds, against saline3

Corneal defect closed
60 %

6 of 10 after 4 weeks with eye drops, placebo 1 of 8 (phase 3)7

Phase 3 in the registry
5 trials

all with eye drops, as of 26 Oct 202611

  • TB-500 is sold as a derivative of thymosin beta-4, a peptide of 43 amino acids that the body makes itself. In almost all cells it binds free actin, the building block of the cell skeleton.21
  • In cell and animal experiments thymosin beta-4 promoted cell migration and new vessel formation. In rats with skin wounds 61 percent more new skin grew after 7 days than with saline.23
  • In humans the full thymosin beta-4 was tested, not the product TB-500: as eye drops up to phase 3, as a gel for skin ulcers and into a vein after heart attack in phase 2.1112
  • In a small phase 3 trial a slow-healing corneal defect closed in 6 of 10 eyes with drops, on placebo in 1 of 8. The difference narrowly missed the statistical threshold.7
  • Thymosin beta-4 is not approved anywhere. Everything here is the state of research, not a recommendation.12
Profile

Updated May 2026

Class
Thymosin beta-4 fragment

regeneration peptide

Route
Subcutaneous
Frequency
Loading 2x/week

then less often

Form
Lyophilised powder

reconstituted with BAC water

Sizes
5 to 20 mg

3 sizes in the shop

Contents 17 sections
  1. At a glance
  2. What is TB-500?
  3. How it works
  4. What you need
  5. Reconstitution
  6. Injection
  7. Dosing
  8. What the research shows
  9. Research status
  10. On the skin
  11. Side effects
  12. Practice
  13. Storage
  14. Related compounds
  15. FAQ
  16. Glossary
  17. Sources

What is TB-500?

TB-500 is described as a fragment, meaning a piece, of thymosin beta-4 (Mendias & Awan, 2026). Thymosin beta-4 itself is a protein of 43 amino acids that the body makes, occurs in almost all cells and is involved in tissue repair, cell migration and inflammation control. The human studies used full thymosin beta-4. In a research context, TB-500 is used for regeneration, tendon and ligament health and mobility.

Unlike BPC-157, which people like to inject locally, TB-500 acts more systemically and distributes well through the body. It ships as a freeze-dried powder you dissolve in bacteriostatic water.

Comparison

TB-500 and its relatives

TB-500 next to the short fragment, the starting piece Ac-SDKP and BPC-157, as stated in the TPD lexicon. Tap a card to open its entry.

Thymosin beta-4, systemic TB-500 (Thymosin Beta-4) ActinILK
Short fragment (actin-binding site) TB-500 FRAG Actin Starting piece Ac-SDKP, does not bind actin TB-500 FRAG 1-4 (Ac-SDKP) Different peptide, more local BPC-157

Simplified: only full thymosin beta-4 was tested in humans, the fragments and blends not in phase 3. 212

How it works

The compound binds actin, a central building block of the cell skeleton. That way it supports the migration of repair and progenitor cells to a site of damage. On top come effects on the formation of new blood vessels and on dampening inflammation.

In a research context, thymosin beta-4 is studied for wound healing and heart tissue, among others. The effects are spread across the whole body, not just at the injection site.

Where it acts

Where thymosin beta-4 acted in studies

Tap a point or a card. Colour = target, grey = observed. Almost everything from animal studies or with eye drops.

  1. Skin and wounds

    Up to 61 percent more new skin after 7 days, more collagen and vessels (rats)3

    Actin
  2. Eye (cornea)

    Defect closed with drops in 6 of 10, placebo 1 of 8 (phase 3)7

    Observed in trials
  3. Heart

    More surviving heart muscle cells and better pump function after infarction (mice)4

    ILK
  4. Blood vessels

    The actin-binding motif alone was enough for new vessel formation (cells)2

    Actin

Known targets2

Compound CHEMBL4594314: two described targets, type of action on each card.

Actin (cell skeleton)
Gene
ACTB
UniProt
P60709
ChEMBL
CHEMBL2062353
Action
Binds free actin via a motif of seven amino acids, not a receptor agonist
Integrin-linked kinase
Gene
ILK
UniProt
Q13418
ChEMBL
CHEMBL5247
Action
Forms a complex with PINCH and ILK that switches on the survival signal Akt (mice and cells)
Two translucent tissue tubes of glass fibres with a gap between them, blue 3D molecules sit on the fibres and at the break
Actin, cell migration, repair. Symbolic image.

What you need

For subcutaneous use you need:

Supplies

5 things, numbered as in the picture

Tick off what you already have. Vial and BAC water are our real shop photos at the same size.

TB-500 vial and bacteriostatic water at the same size with the black TPD label, next to two U-100 insulin syringes, two alcohol swabs and a sharps container with a blue lid

  1. TB-500 vial

    The TB-500 vial with the freeze-dried powder

    In the shop

  2. Bacteriostatic water

    Bacteriostatic water to dissolve it

    In the shop

  3. U-100 insulin syringes

    U-100 insulin syringes

    Amazon (opens a new tab)

  4. Alcohol swabs

    Alcohol swabs for the vial cap and the skin

    Amazon (opens a new tab)

  5. Sharps container

    A sealable sharps container for used needles

As an Amazon associate we earn from qualifying purchases. Links open Amazon - no extra cost for you.

Reconstitution

The powder is dissolved in bacteriostatic water. How much water you add sets the concentration and therefore how many units you draw for your dose on the insulin syringe.

Use the peptide calculator for this: pick your vial size and the water volume to see the concentration and units per dose.

When dissolving, just add the bac water, it does not matter if it hits the powder directly. Then swirl or shake until everything has dissolved, both are fine.

Step by step

Dissolving the powder

Four steps, the same for every vial size.

  1. 1Wipe the cap

    Clean the rubber stopper with an alcohol swab.

  2. 2Add BAC water

    Just add it, it does not matter if it hits the powder directly.

  3. 3Swirl or shake

    Until everything has dissolved, both are fine.

  4. 4Draw up

    With the U-100 insulin syringe.

Less water higher concentration fewer units on the syringe Example: 10 mg + 2 ml = 5 mg/ml

Injection

Because TB-500 acts systemically, the exact site matters less than with BPC-157. Classically it is injected subcutaneously into the abdomen (keep clear of the area around the navel), the front and the inner side of the thigh or the back of the upper arm.

Injection

Where and at what angle

Pick a spot or switch the angle. Subcutaneous means: into the fat layer, not the muscle.

Rotate the spot each time, never the same one twice in a row.

90°More fat under the skin

Rule of thumb: where there is more fat under the skin, insert straight at 90 degrees. In lean people with little fat, 45 degrees, so the needle stays in the fat layer. Simplified diagram.

  1. Clean the spot with an alcohol swab and let it dry

  2. Pinch up a small fold of skin

  3. Insert the needle: at 90 degrees where there is more fat under the skin, at 45 degrees in lean people with little fat

  4. Inject slowly, wait a moment, then withdraw

  5. Put the needle straight into the sharps container

Rotate the site.

Dosing

Dosing

Dosing, titration and syringe

Loading the dosing information …

  • Getting started and stepping up, drawn as a staircase
  • Units on the U-100 syringe for every step
  • How long one vial lasts
TB-500 vial on light blue stone with a closed notebook and an insulin syringe
Symbolic image.

What the research shows

Thymosin beta-4 is well described mechanistically and was studied in early clinical approaches for wound healing and heart tissue. A review summarises structure, function and clinical potential. For injection under the skin, large approval trials are missing. As eye drops, however, thymosin beta-4 went up to phase 3: for dry eye in the completed trials ARISE-2 (601 participants) and ARISE-3 (700 participants) and for a corneal disease (neurotrophic keratopathy) in a small phase 3 trial with 18 participants (Sosne, 2022). It is not approved so far. TB-500 as a research form is not the same as an approved medicine. That belongs in the picture honestly.

The source with a link is in the source block below.

Study results

What the trials measured

Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.

Closed corneal defect after 4 weeks7

Share with a fully closed defect in neurotrophic keratopathy, eye drops against placebo

Defect fully closed7 6 of 10 against 1 of 8
Placebo 12.5%
Thymosin beta-4 60.0%

Very small phase 3 trial with 18 participants, stopped early. The difference was just above the significance threshold (p = 0.0656). Two weeks after the drops ended no defect returned in the thymosin group.

Discomfort in the provocation test6

Difference from placebo after 28 days of eye drops, phase 2 with 72 participants

Eye discomfort in a dry test chamber6
Thymosin beta-4 -27%

The two primary endpoints (discomfort and staining of the lower cornea on day 29) did not differ. Secondary endpoints such as this value from the provocation test on day 28 were significant.

Wound healing in rats3

More than in the saline control group, applied to the skin or into the abdominal cavity

New skin after 4 days3
Thymosin beta-4 (rats) 42%
New skin after 7 days3
Thymosin beta-4 (rats) 61%
Wound contraction after 7 days3
Thymosin beta-4 (rats) 11%

Animal study with full thymosin beta-4. The wounds also showed more collagen and more new vessels.

Row of sealed test tubes with clear liquid, each with a glass heart inside, one of them glowing brightly
Full thymosin beta-4 was tested, not TB-500. Symbolic image.

Research status

Where the research stands

Shown are the registered trials with full thymosin beta-4: eye drops, a gel for the skin and infusion after heart attack. None of them tests TB-500 under the skin. As of 26 Oct 2026. 11

  1. Preclinical Wound healing, vessel formation and heart in cells and animals
  2. Phase 1 2 trials, 2 completed
  3. Phase 2 10 trials, 6 completed, 3 stopped early
  4. Phase 3 5 trials, 3 completed, 1 stopped early
  5. Approval not yet
1,706 participants in phase 3 Planned figures for running trials Not approved. ChEMBL lists thymosin beta-4 with phase 3 as the highest phase, reached only as eye drops. TB-500 itself has not been tested in any human study.12
Show all 15 phase 2 and 3 trials on a timelineHide timeline 9 completed 2 running 4 stopped early 1 with results
Phase 2
Phase 3

Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 26 Oct 2026, grey = stopped early. Phase 1: 2 trials on safety and pharmacokinetics, not shown as bars.

On the skin

Besides the eye drops, thymosin beta-4 was also tested in humans as a gel applied directly to wounds. In two phase 2 trials in leg ulcers and pressure ulcers wound closure was about a month faster in participants whose wounds closed fully (Treadwell 2012). The review comes from the developer's side. All of these studies used the full thymosin beta-4, not the research form TB-500.

Hand touching a swirl of white cream on a light marble slab with water droplets and white flowers
Symbolic image.

Side effects

TB-500 is considered well tolerated. Mostly mild things are reported: injection-site reactions, occasionally brief tiredness after dosing. Solid long-term human safety data are limited, so phases make more sense than continuous running.

Tolerability

Side effects in the phase 2 trial with eye drops

Out of 100 participants, how many had a side effect. Eye drops with thymosin beta-4 against placebo, no injection under the skin.

0 of 100 Placebo
0 of 100 Thymosin beta-4
Event PlaceboThymosin beta-4
Any side effect6 0%0%

Zero does not mean safe here. Given into a vein, 40 healthy people tolerated thymosin beta-4 for 14 days without serious side effects. There are no solid human data for TB-500 under the skin.6510

Practice

  1. Run it in phases: loading first, then maintenance, then a break.

  2. TB-500 is often combined with BPC-157: BPC more locally, TB-500 systemically.

  3. Sleep, protein and rest support the regeneration.

White foam roller, a light blue exercise band and a glass of water on a light wooden floor in a bright room

Storage

The undissolved powder is robust, normal room temperature (around 20 to 25 degrees) is fine, ideally kept in the dark. The reconstituted solution goes into the fridge (2 to 8 degrees) and stays stable there for at least 4 to 6 months with barely any loss of potency, in practice considerably longer. The bacteriostatic water brings a preservative that keeps the dissolved form stable for longer.

Shelf life

How long it keeps

Undissolved (powder) Room temperature, around 20 to 25 degrees, dark

Robust, no fridge needed.

Dissolved (mixed) Fridge, 2 to 8 degrees, do not freeze

At least 4 to 6 months with barely any loss of potency. The bacteriostatic water brings a preservative.

  • Keep it dark
  • Dissolved: 2 to 8 degrees
  • Note the mixing date on the vial
Nine vials with white powder and blue caps in the door shelf of a bright fridge
Powder dark at room temperature, once dissolved into the fridge (2 to 8 degrees), stable there for at least 4 to 6 months. Symbolic image.

Related

Related compounds

Same targets, blends with TB-500 (Thymosin Beta-4) or a different path: all in the TPD lexicon.

TB-500 (Thymosin Beta-4)
TB-500 FRAG Only the actin-binding site of thymosin beta-4 TB-500 FRAG 1-4 (Ac-SDKP) The first four amino acids (Ac-SDKP), its own pathway BPC + TB Blend Contains TB-500 plus BPC-157 BPC + TB + KPV Blend Contains TB-500 plus BPC-157 and KPV BPC + TB Oral Blend TB-500 and BPC-157 as a tablet Klow Blend Contains TB-500 plus BPC-157, GHK-Cu and KPV Glow Blend Contains TB-500 plus BPC-157 and GHK-Cu BPC-157 Often combined with TB-500, more local

FAQ

Common questions about TB-500 (Thymosin Beta-4)

Short answers, each backed by the sources below.

Is TB-500 the same as thymosin beta-4?

Not quite. TB-500 is described as a fragment, meaning a piece, of thymosin beta-4. All human studies used full thymosin beta-4 of 43 amino acids, made synthetically or by genetic engineering. A 2026 review finds hardly any solid human safety data for the freely traded peptides.2510

How does thymosin beta-4 work?

It keeps free actin in reserve inside the cell and so influences how cells migrate. In experiments a motif of seven amino acids was enough for new vessel formation. In the hearts of mice it formed a complex with PINCH and the kinase ILK that switches on the survival signal Akt.24

What do the eye studies show?

Thymosin beta-4 as eye drops reached phase 3. In a rare corneal disease the defect closed in 6 of 10 eyes, on placebo in 1 of 8, narrowly without statistical certainty. For dry eye a phase 2 trial missed its main goals, but discomfort in the provocation test was 27 percent lower than on placebo.76

Was thymosin beta-4 also applied to the skin?

Yes. Besides the eye drops, a thymosin beta-4 gel was applied directly to leg ulcers and pressure ulcers in two phase 2 trials. In those whose wounds closed, this happened about a month sooner. The review comes from the developer's side and the full thymosin beta-4 was tested, not TB-500.9

And in the heart?

In mice after infarction more heart muscle cells survived and pump function was better. In a Chinese study with 96 heart attack patients the infarct area was smaller only in the group dosed early, across all participants there was no significant difference.48

Is thymosin beta-4 approved?

No. ChEMBL lists it with phase 3 as the highest phase, reached only as eye drops. Studies as a gel for skin and pressure ulcers and into a vein after heart attack reached phase 2.12119

Which side effects are known?

In the phase 2 trial with eye drops no side effect occurred. 40 healthy people tolerated thymosin beta-4 into a vein for 14 days without serious side effects, complaints were rare and mild to moderate. There is no study on TB-500 under the skin.65

Glossary

Terms explained briefly

Dotted words in the text open these explanations directly.

Actin
Structural protein of the cell skeleton, needed for cell shape and movement.
Approval trial
A large phase 3 trial on whose result an authority decides about approval.
Cell migration
Movement of cells to a wound or into new tissue, a basic step of any repair.
ILK
Integrin-linked kinase: a hub that passes signals from the cell surface into the cell, among them signals for cell survival.
Lyophilisate
Freeze-dried powder. Without water a peptide keeps much longer.
Neurotrophic keratopathy
A rare corneal disease in which damaged nerves let the surface heal poorly.
New vessel formation
The formation of new small blood vessels, for example in healing tissue.
Subcutaneous
Into the fat layer just under the skin.
Systemic
Spread through the whole body, not only at the site of administration.
Thymosin beta-4
A peptide of 43 amino acids made by the body. It occurs in almost all cells and binds free actin.

Evidence

Sources

Show all 12 sourcesHide sources 9 Studies1 Trial registry2 Database checked 26 Oct 2026

Studies

  1. The actin-binding site of thymosin beta-4 promotes new vessel formation

    Philp et al., The FASEB Journal, 2003

    DOI 10.1096/fj.03-0121fje PMID 14500546
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  2. Thymosin beta-4 accelerates wound healing (rats)

    Malinda et al., Journal of Investigative Dermatology, 1999

    DOI 10.1046/j.1523-1747.1999.00708.x PMID 10469335
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  3. Thymosin beta-4 and cardiac repair (mice)

    Bock-Marquette et al., Nature, 2004

    DOI 10.1038/nature03000 PMID 15565145
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  4. Thymosin beta-4 into a vein in 40 healthy adults

    Ruff et al., Annals of the New York Academy of Sciences, 2010

    DOI 10.1111/j.1749-6632.2010.05474.x PMID 20536472
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  5. Phase 2 trial with eye drops for dry eye

    Sosne und Ousler, Clinical Ophthalmology, 2015

    DOI 10.2147/OPTH.S80954 PMID 26056426
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  6. Phase 3 trial with eye drops for neurotrophic keratopathy

    Sosne et al., International Journal of Molecular Sciences, 2022

    DOI 10.3390/ijms24010554 PMID 36613994 NCT02600429
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed, PMC (Volltext)
  7. Recombinant thymosin beta-4 after heart attack (mice and patients)

    Zhang et al., Cardiovascular Research, 2025

    DOI 10.1093/cvr/cvaf223 PMID 41229390
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  8. Review of thymosin beta-4 for skin wounds, animals and phase 2

    Treadwell et al., Annals of the New York Academy of Sciences, 2012

    DOI 10.1111/j.1749-6632.2012.06717.x PMID 23050815
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  9. Review of approved and unapproved peptides in sport

    Mendias und Awan, Sports Medicine, 2026

    DOI 10.1007/s40279-026-02437-0 PMID 41966639
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed

Trial registry

  1. Trials with thymosin beta-4 on ClinicalTrials.gov

    ClinicalTrials.gov, U.S. National Library of Medicine

    Checked 26 Oct 2026 via ClinicalTrials.gov API v2

Database

  1. Review of the structure, function and clinical potential of thymosin beta-4 (PubMed record)

    Crockford et al., Annals of the New York Academy of Sciences, 2010 (DOI 10.1111/j.1749-6632.2010.05492.x)

    PMID 20536467
    Checked 26 Oct 2026 via PubMed, doi.org, Crossref
  2. Thymosin beta-4 in ChEMBL (highest phase 3)

    ChEMBL, EMBL-EBI (CHEMBL4594314)

    Checked 26 Oct 2026 via ChEMBL

In the shop

TB-500 (Thymosin Beta-4) in the catalog

Sizes, prices and shipping times are on the product page.

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