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Research use only · common protocol

TB-500 5 mg vial dosage

A 5 mg TB-500 vial mixed with 1 mL of bacteriostatic water gives 5 mg/mL, so 2.5 mg is 50 units (0.5 mL) on a U-100 insulin syringe. At 2.5 mg a dose, one vial holds 2 doses.

Email me this plan, with a reminder before the vial's 28-day mark →

The common TB-500 protocol is 2-2.5 mg, twice weekly during a 4-6 week loading phase, then once weekly (or every two weeks) for maintenance - common practice, not a dose established in trials. Evidence, side effects and legal status are on the full TB-500 dosing page.

TB-500 5 mg vial at a glance

Vial
5 mg of TB-500 per vial
Common dose
2-2.5 mg
How often
twice weekly during a 4-6 week loading phase, then once weekly (or every two weeks) for maintenance
Mixing example
1 mL bacteriostatic water = 5 mg/mL; 1 unit = 50 mcg
Doses per vial
2 at 2 mg · 2 at 2.5 mg
Cycle
4-6 weeks, then 4-6 weeks off

What TB-500 is

Class:
Synthetic heptapeptide fragment
Also called:
Ac-LKKTETQ, Thymosin beta-4 fragment (17-23), TB4 fragment
Used for:
Marketed for tissue repair and injury recovery. I could not locate a completed, published human randomized trial for any musculoskeletal or tissue-repair indication.
Human evidence:
Animal / lab only. In vitro and animal work only. I could not locate a published human randomized controlled trial of the heptapeptide for any indication. Much of the tissue-repair literature cited for TB-500 appears to have studied full-length thymosin beta-4 - a different molecule - so even the preclinical base is likely thinner than it looks. There is no human evidence here that I could find.
US status:
Research use only. Not FDA-approved in the US for any indication and sold as a research chemical. Prohibited at all times in sport under WADA 2026 section S2.3, listed as "Thymosin-ß4 and its derivatives e.g. TB-500".

The full picture, with every study: TB-500 guide.

Units per dose: TB-500 5 mg vial

Water addedConcentration1 unit =2 mg2.5 mg
1 mL5 mg/mL50 mcg40 units50 units
1.5 mL3.33 mg/mL33.33 mcg60 units75 units
2 mL2.5 mg/mL25 mcg80 units100 units

U-100 insulin syringe (100 units = 1 mL), to the nearest half unit. Water volumes are examples. Other numbers: dosage calculator.

Every dose from 2 mg to 2.5 mg, in units

With 1 mL of water in a 5 mg vial (5 mg/mL). Every dose across the common range, so you can read off any dose. The sources give a range, not a week-by-week schedule.

DoseDraw on a U-100 syringeVolumeDoses per vial
2 mg40 units0.4 mL2
2.1 mg42 units0.42 mL2
2.2 mg44 units0.44 mL2
2.3 mg46 units0.46 mL2
2.4 mg48 units0.48 mL2
2.5 mg50 units0.5 mL2

How many doses a 5 mg vial holds

DoseDoses per vialWeeks per vial
2 mg21-2
2.5 mg21-2

Weeks per vial at the common frequency (twice weekly during a 4-6 week loading phase, then once weekly (or every two weeks) for maintenance). Doses per vial do not depend on how much water you add.

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The common TB-500 protocol

Dose2-2.5 mg per injection
How oftentwice weekly during a 4-6 week loading phase, then once weekly (or every two weeks) for maintenance
TimingMorning, on an empty stomach; injection site rotated between abdomen, thigh and upper arm.
RouteSubcutaneous injection
Cycle4-6 weeks
Break4-6 weeks
Often paired withBPC-157, Sermorelin
Sources agree?Yes, the sources give the same protocol

Common practice from the vendors and clinics that publish it, not a dose tested in trials. Where it comes from: [1], [2], [3]. I do not give week-by-week titration: none of these sources states one.

Supplies for one cycle with 5 mg vials

Counted for the low and high ends of the common protocol, mixing each vial with 1 mL of water. One new syringe per injection.

PlanInjections5 mg vialsInsulin syringesBacteriostatic waterAlcohol swabs
2 mg, 1×/week, 4 weeks4242 mL (1 × 10 mL bottle)12 (1 × 100-pack)
2.5 mg, 2×/week, 6 weeks126126 mL (1 × 10 mL bottle)36 (1 × 100-pack)

Arithmetic on the protocol and this vial size. Swabs: two per vial mixed (both stoppers) and two per injection (vial stopper and skin). An opened multi-dose vial has a use-by date (see storage), which on a slow schedule can matter more than the dose count. Plan your own numbers with the protocol builder.

How to mix a 5 mg TB-500 vial

For this vial: 1 mL of bacteriostatic water makes 5 mg/mL, so 2.5 mg is 50 units (0.5 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

  1. Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. [4][5]
  2. With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. [4][5][6]
  3. Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. [7]
  4. Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. [4][5][7]
  5. Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. [4]
  6. Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. [7]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing TB-500 vials

  • Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. [8]
  • Protect peptide vials from heat and light. [8][9]
  • Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. [7][8]
  • Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. [10][11]

More detail: peptide storage and shelf life.

Injecting safely

  • Clean the injection site with an alcohol swab and let the skin dry completely before injecting. [12][13]
  • Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. [12][13][14]
  • Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. [12]
  • Inject slowly, at roughly 10 seconds per mL. [12]
  • Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. [7][12][13]

Hygiene and warning signs

  • Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. [6][10][13]
  • Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. [6][9][10]
  • Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. [15][16]
  • Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. [13]

Where to inject: subcutaneous injection sites.

How TB-500 works

  • TB-500 is a synthetic seven-amino-acid peptide, Ac-LKKTETQ: amino acids 17 to 23 of the 43-amino-acid protein thymosin beta-4, with an acetyl group added to the first amino acid. Mass-spectrometry analysis identified this acetylated fragment in a product sold as TB-500. [17][18]
  • Its sequence contains the stretch of thymosin beta-4 that binds actin, a building block of the cell's internal skeleton. Thymosin beta-4 holds single actin units in reserve, which affects cell shape and movement, and reviews link the LKKTETQ region to cell migration, new blood-vessel growth and wound healing. [17][19]
  • FDA notes that adding the acetyl group changes a peptide's charge, size and binding, so results from the plain LKKTETQ fragment cannot be assumed to apply to TB-500. It also remains unknown whether actin binding explains any of the fragment's reported effects. [17]
  • TB-500 is broken down by trimming amino acids from its tail end, giving shorter fragments such as Ac-LKKTE, Ac-LKK and Ac-LK. This was seen in human serum and human liver and kidney preparations in the lab, and in the urine of treated rats and horses. [17][20]

What the TB-500 research found

Human evidence: animal / lab only. Each result says what was studied.

  • Animal studyIn a 2026 study of 32 rats with a cut and repaired Achilles tendon, TB-500 given for four weeks produced significantly higher breaking strength and better tissue scores than no treatment. Combining it with BPC-157 gave no extra benefit. [21]
  • Lab studyIn a lab scratch-wound test on fibroblasts, TB-500 itself did not significantly speed wound closure compared with control; only one of its breakdown products, Ac-LKKTE, did. The authors suggest earlier wound-healing reports may reflect that metabolite rather than TB-500. [17][20]
  • Animal studyIn aged mice, the non-acetylated seven-amino-acid fragment LKKTETQ applied to skin wounds promoted repair about as well as full-length thymosin beta-4. This was not TB-500 itself, which carries an acetyl group. [22]
  • Regulator reviewIn horses given a single 10 mg injection under the skin, blood levels of TB-500 peaked 1 to 2 hours later and could no longer be measured after 6 to 10 hours. [17]
  • Lab studyA 2023 analysis of products sold online as TB500 and TB1000 found their contents did not consistently match how the products had been described. [23]

TB-500 side effects and risks

TB-500 has never been tested in a published human study. FDA's 2026 review found no human exposure data by any route, no TB-500 reports in its adverse-event database up to March 2025, and no animal toxicity studies, so its safety in people is unknown.

  • Regulator reviewFDA's adverse-event database holds a report of a 40-year-old woman who injected a combined BPC-157 and TB-500 product twice daily and developed widespread skin darkening and darkened gums, which returned when she used it again. Because the product held two peptides, FDA could not say which caused it. [24]
  • Lab studyIn the fibroblast study, neither TB-500 nor its breakdown products were toxic to the cells. [20]

Other things to know

  • Widely sold and discussed as if it were thymosin beta-4. It is not. Evidence generated on the full-length protein does not transfer to the fragment, so buyers may be reasoning from the wrong literature.
  • I could not locate a published human randomized controlled trial for any tissue-repair indication, and there is no established human half-life.
  • Sold as a research chemical, so purity, identity and dose are not verified by any regulator.
  • Prohibited at all times in sport (WADA S2.3). It is also reported to have been encountered as a designer drug in racehorses.

Reported side effects and what the studies measured: TB-500 side effects.

Where this vial size comes from

TB-500 is sold as a 5 mg vial by the pages below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

  • Spartan PeptidesvendorLists it as: TB-500 Thymosin Beta-4 size options include 5mg · checked 2026-09-28
  • Next Level PharmvendorLists it as: TB500 size dropdown includes 5mg · checked 2026-09-28

The doses come from the sourced common protocol on the TB-500 dosing page, and every number on this page is arithmetic on those doses and this vial size.

Other TB-500 vial sizes

Where to buy TB-500 for research

Sold for research use only. Listed by Next Level Pharm, Spartan Peptides and BioEdge Research Labs; compare them on my vendors page or see the listing on the TB-500 page.

Questions

How much water do I add to a 5 mg TB-500 vial?
There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1 mL the vial is 5 mg/mL and 2.5 mg is 50 units (0.5 mL) on a U-100 insulin syringe. The units table gives 1, 1.5, 2 mL.
How many doses are in a 5 mg TB-500 vial?
2 doses at 2 mg, 2 doses at 2.5 mg.
How long does a 5 mg TB-500 vial last?
At 2.5 mg a dose and twice weekly during a 4-6 week loading phase, about 1-2 weeks. How long a mixed vial keeps is a separate limit; see storage below.
How many 5 mg vials do I need for a cycle?
2 vials at 2 mg 1 time a week for 4 weeks; 6 vials at 2.5 mg 2 times a week for 6 weeks.
What does 1 unit equal in a 5 mg TB-500 vial?
50 mcg with 1 mL, 33.33 mcg with 1.5 mL, 25 mcg with 2 mL of bacteriostatic water, on a U-100 syringe.

References (24 sources)

  1. [1] Path To Peptides: 2.5mg SC per injection, twice weekly for weeks 1-6 (loading), once weekly from week 7 (maintenance), 10mg vial, morning fasted, empty stomach (other, checked 2026-09-27)
  2. [2] TB500.org: 2-2.5mg SC or IM per injection, twice weekly loading for 4-6 weeks, then once weekly or every two weeks maintenance, cycle off 4-6 weeks after a full maintenance course; commonly paired with BPC-157 or Sermorelin (vendor, checked 2026-09-27)
  3. [3] Perfect B (Valeria Marulanda, FNP-BC, NPI 1841152584, Doral FL): Real named aesthetic-medicine clinic prescribing TB-500 within a combined BPC-157+TB-500 'Wolverine' blend vial, dose titrated by the provider month to month; 5 days on/2 days off, up to 3 cycles back to back, then a 2-month break; administered before bedtime, subcutaneous (clinic, checked 2026-09-27)
  4. [4] OpenStax, Rice University: 12.3 Preparing Unit-Dose Packaged Medications - Clinical Nursing Skills
  5. [5] East Carolina University College of Nursing: Reconstitution of Medication
  6. [6] Centers for Disease Control and Prevention: Considerations for Blood Glucose Monitoring and Insulin Administration
  7. [7] DailyMed, National Library of Medicine: SEROSTIM (somatropin) for injection - prescribing information and instructions for use
  8. [8] GenScript: Peptide Storage and Handling Guidelines
  9. [9] DailyMed, National Library of Medicine: OZEMPIC (semaglutide) injection - prescribing information
  10. [10] Centers for Disease Control and Prevention: Preventing Unsafe Injection Practices
  11. [11] Pfizer: Bacteriostatic Water for Injection, USP - prescribing information
  12. [12] OpenStax, Rice University: 12.5 Administering Subcutaneous Injections - Clinical Nursing Skills
  13. [13] MedlinePlus, National Library of Medicine: Subcutaneous (SQ) injections
  14. [14] Centers for Disease Control and Prevention: Chapter 6: Vaccine Administration - Pink Book
  15. [15] US Food and Drug Administration: Best Way to Get Rid of Used Needles and Other Sharps
  16. [16] US Food and Drug Administration: DOs and DON'Ts of Proper Sharps Disposal
  17. [17] US Food and Drug Administration: FDA Briefing Document, Pharmacy Compounding Advisory Committee meeting of 23-24 July 2026: evaluation of TB-500 (free base) and TB-500 acetate
  18. [18] Esposito S, Deventer K, Goeman J et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal. 2012;4(9):733-8.
  19. [19] Sosne G, Qiu P, Goldstein AL et al. Biological activities of thymosin beta4 defined by active sites in short peptide sequences. FASEB J. 2010;24(7):2144-51.
  20. [20] Rahaman KA, Muresan AR, Min H et al. Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro. J Chromatogr B Analyt Technol Biomed Life Sci. 2024;1235:124033.
  21. [21] Biçer O, Adanir O, Güleryüz Y et al. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. Jt Dis Relat Surg. 2026;37(3):822-837.
  22. [22] Philp D, Badamchian M, Scheremeta B et al. Thymosin beta 4 and a synthetic peptide containing its actin-binding domain promote dermal wound repair in db/db diabetic mice and in aged mice. Wound Repair Regen. 2003;11(1):19-24.
  23. [23] Delcourt V, Garcia P, Chabot B et al. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Test Anal. 2023;15(4):458-464.
  24. [24] US Food and Drug Administration: FDA Briefing Document, Pharmacy Compounding Advisory Committee meeting of 23-24 July 2026: evaluation of BPC-157 (free base) and BPC-157 acetate