Quick Answer: TB-500 has no FDA-approved human dose and no human clinical trial — in its 2026 review the FDA found no clinical study of TB-500 in people by any route. TB-500 is a synthetic 7-amino-acid fragment (Ac-LKKTETQ, residues 17–23) of thymosin beta-4, and it is not the same substance as full-length thymosin beta-4. The doses discussed online (often 2–2.5 mg) come from clinics and guides, not studies. This calculator only does the reconstitution maths for a vial — it does not recommend a dose.
TB-500 Reconstitution Calculator
Enter your vial strength, the BAC water you add, and a dose amount to see the concentration, the volume to draw and the U-100 syringe units.
For research purposes only · Not medical advice · peptidecalcu.com
How the TB-500 Dosage Calculator Works
The calculator needs three numbers:
- Vial strength (mg) — the total TB-500 powder in the vial, printed on the label (commonly 2 mg, 5 mg or 10 mg).
- BAC water volume (mL) — how much bacteriostatic water you add. This alone sets the concentration.
- Dose amount (mcg or mg) — the amount you want the maths for. The calculator converts it into mL and syringe units.
The formula
Concentration (mg/mL) = vial strength (mg) ÷ BAC water (mL). Volume per dose (mL) = dose (mg) ÷ concentration (mg/mL). Syringe units = volume (mL) × 100 on a U-100 insulin syringe (1 unit = 0.01 mL).
Worked example
| TB-500 vial strength | 5 mg |
| BAC water added | 2 mL |
| Final concentration | 2.5 mg/mL (2,500 mcg/mL) |
| Dose amount entered | 500 mcg |
| Volume to draw | 0.20 mL |
| Syringe units (U-100) | 20 units |
| Doses in the vial | 10 |
TB-500 Mixing Chart
| Vial strength | BAC water | Concentration | 250 mcg | 500 mcg | 1 mg | 2 mg |
|---|---|---|---|---|---|---|
| 2 mg | 1 mL | 2 mg/mL | 12.5 u | 25 u | 50 u | 100 u |
| 5 mg | 1 mL | 5 mg/mL | 5 u | 10 u | 20 u | 40 u |
| 5 mg | 2 mL | 2.5 mg/mL | 10 u | 20 u | 40 u | 80 u |
| 5 mg | 3 mL | 1.67 mg/mL | 15 u | 30 u | 60 u | — * |
| 10 mg | 2 mL | 5 mg/mL | 5 u | 10 u | 20 u | 40 u |
| 10 mg | 4 mL | 2.5 mg/mL | 10 u | 20 u | 40 u | 80 u |
* 2 mg at this concentration is 1.2 mL — more than a 1 mL syringe holds. This chart is a maths reference only, not a dosing guide.
What Is TB-500?
TB-500 is the commercial name for a synthetic peptide made of just seven amino acids: Ac-LKKTETQ. That sequence copies residues 17–23 of thymosin beta-4 (Tβ4), a 43-amino-acid protein found naturally in almost all human cells. The copied stretch is Tβ4’s actin-binding domain — the part that interacts with actin, the protein cells use to move and change shape, which is why the fragment is studied in cell-migration and wound-repair models.
Two identity facts matter more than anything else on this page:
- TB-500 is not thymosin beta-4. The FDA states this plainly. Human trials of eye drops, skin gels and IV preparations used the full-length Tβ4 molecule (timbetasin) — those results cannot be relabelled as TB-500 results.
- What is sold as TB-500 varies. The name was first chemically identified by doping-control laboratories analysing seized and veterinary products, which found the acetylated fragment Ac-LKKTETQ. Products sold under the same name have also been found to contain other substances, so a label alone does not prove content.
What Does the Evidence Actually Show?
For the TB-500 fragment itself, the direct evidence is thin and preclinical:
- In a 2003 mouse study, the synthetic LKKTETQ peptide promoted dermal wound repair in diabetic (db/db) and aged mice to a degree comparable with full-length thymosin beta-4 (Philp et al., 2003).
- Full-length Tβ4 has a much larger research record — reviews describe roles in cell migration, angiogenesis and inflammation in animal and cell models (Goldstein et al., 2005; Kleinman & Sosne, 2016) — but again, that is the parent protein, not TB-500.
- For TB-500 itself, the FDA’s 2026 review searched the published literature, ClinicalTrials.gov and its own adverse-event systems and found no clinical study and no human exposure data by any route, and no animal toxicity studies. There is no established human dose, half-life or safety profile.
Amounts of 2–2.5 mg a few times a week, and lower amounts of 500 mcg–1 mg, circulate in online guides and clinic protocols. None of them has been tested in a human study of TB-500, so this page presents them only as amounts discussed online — the calculator above will do the maths for any amount you enter, without endorsing one.
TB-500 vs BPC-157
| TB-500 | BPC-157 | |
|---|---|---|
| What it is | 7-amino-acid fragment of thymosin beta-4 (Ac-LKKTETQ) | 15-amino-acid peptide derived from a gastric protection protein |
| Main research angle | Actin binding, cell migration, angiogenesis | Nitric-oxide system, growth-hormone receptor, gut and tendon models |
| Human evidence | None found for the fragment (FDA, 2026) | A handful of small reports; a 2025 review found 35 of 36 studies preclinical |
| FDA-approved? | No | No |
| WADA status | Named explicitly — prohibited at all times (S2) | Prohibited as a non-approved substance (S0) |
The two are often combined in what is sold as a ‘Wolverine stack’. There is no human study of the combination. Compare the maths side by side with our BPC-157 dosage calculator.
Regulatory and Sporting Status
- FDA approval: TB-500 is not FDA-approved for any use, in any form.
- Compounding: The FDA placed TB-500 (thymosin beta-4 fragment) in Category 2 of its 503A compounding policy in September 2023. It was removed from Category 2 in April 2026 after its nomination was withdrawn — removal is not an authorisation. In July 2026 the FDA’s Pharmacy Compounding Advisory Committee voted 8–6 to recommend adding it to the 503A Bulks List, against FDA staff’s recommendation. A committee vote is advisory: until FDA rulemaking finishes, TB-500 is not on the 503A Bulks List.
- Sport: The WADA Prohibited List bans ‘thymosin-β4 and its derivatives, e.g. TB-500’ at all times, in and out of competition, under S2 (growth factors). Tested athletes face a strict-liability violation.
Storage and Handling
- Lyophilised (powder) vials: store sealed, dry and cold — refrigerated for short periods, frozen for long-term storage.
- After reconstitution with BAC water: refrigerate at 2–8 °C, keep the vial upright and out of the fridge door, and do not freeze the solution.
- Label the vial with the compound, the date mixed, and the concentration (for example ‘2.5 mg/mL’) so the calculator maths can be rechecked later.
- Discard any solution that is cloudy, discoloured or past the window your supplier specifies.
Safety note: Because there are no human studies of TB-500, there is no verified list of its side effects, interactions or long-term risks in people — anyone who gives you one is guessing. Unregulated products also carry purity and contamination risks. This page is educational and describes research maths only; it is not medical advice.
Frequently Asked Questions
What is the correct TB-500 dosage?
There isn’t an established one. No human study has tested TB-500 at any dose, so no dose can be called correct, safe or effective. Amounts quoted online come from clinics and community guides, not trials. This calculator converts whatever amount you are researching into mL and syringe units.
Is TB-500 the same as thymosin beta-4?
No. Thymosin beta-4 is a 43-amino-acid protein that occurs naturally in the body. TB-500 is a synthetic 7-amino-acid fragment (Ac-LKKTETQ, residues 17–23) of it. The FDA states the two are not the same substance, and human trial results for thymosin beta-4 do not apply to TB-500.
How much BAC water do I add to a 5 mg TB-500 vial?
2 mL is the most common research dilution and gives a 2.5 mg/mL concentration, so 500 mcg = 0.20 mL = 20 units on a U-100 syringe. Adding 1 mL doubles the concentration (5 mg/mL) and halves every draw volume. Use the mixing chart above for other combinations.
How many doses are in a 10 mg vial?
It depends on the amount per dose: a 10 mg vial holds 20 × 500 mcg, 10 × 1 mg, or 5 × 2 mg. Enter your vial and amount in the calculator and it shows the exact count.
Is TB-500 legal?
TB-500 is not FDA-approved for any use and is not on the FDA’s 503A Bulks List, so licensed US compounding pharmacies cannot routinely compound it. It is widely sold online labelled ‘for research use only’, which does not make it an approved medicine. Rules differ by country.
Can athletes use TB-500?
No. TB-500 is named explicitly on the WADA Prohibited List (‘thymosin-β4 and its derivatives, e.g. TB-500’, category S2) and is banned at all times, in and out of competition.
Can TB-500 and BPC-157 be combined?
They are frequently marketed together (the so-called Wolverine stack), but the combination has never been studied in humans, and neither compound has an established human dose on its own. Combining two unstudied substances adds unknown interaction risk on top of unknown individual risk.
Related Calculators and Guides
- BPC-157 Dosage Calculator
- General Peptide Calculator
- All Peptide Dosage Calculators
- Types of Peptides
- Peptide Guides and Articles
- BPC-157 vs TB-500
References
- Philp D, Badamchian M, Scheremeta B, Nguyen M, Goldstein AL, Kleinman HK. 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 and Regeneration 2003;11(1):19–24. — doi:10.1046/j.1524-475x.2003.11105.x (PMID: 12581423)
- Goldstein AL, Hannappel E, Kleinman HK. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends in Molecular Medicine 2005;11(9):421–429.
- Kleinman HK, Sosne G. Thymosin beta4 promotes dermal healing. Vitamins and Hormones 2016;102:251–275.
- US Food and Drug Administration. Briefing and review materials for TB-500 (thymosin beta-4 fragment, LKKTETQ), Pharmacy Compounding Advisory Committee meeting, 23–24 July 2026 — FDA found no clinical studies or human exposure data for TB-500 by any route. fda.gov
- US Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Category 2 list and substances previously in Category 2; TB-500 listed September 2023, removed April 2026). fda.gov
- World Anti-Doping Agency. The Prohibited List 2026 — S2.3 Growth factors and growth factor modulators: ‘Thymosin-ß4 and its derivatives e.g. TB-500’. wada-ama.org
Last checked: November 2026. Compiled from the primary sources above. This page is not individually medically reviewed and is not medical advice.