Thymosin Beta-4 5 mg vial
How much bacteriostatic water to add to a 5 mg vial of Thymosin Beta-4, the syringe units for each common dose, and how many doses the vial holds.
- Water
- 1 mL
- Strength
- 5 mg/mL
- Common dose
- 2.5 mg
- Draw
- 50 units0.50 mL
- Doses per vial
- 2
The short answer
Mixed with 1 mL of bacteriostatic water, a 5 mg vial of Thymosin Beta-4 holds 5 mg/mL. A 2.5 mg dose is then 50 units (0.50 mL) on a U-100 insulin syringe, and the vial holds about 2 doses of that size. Taken 2× per week, it lasts about 7 days.
How much water
The water only sets the strength; the dose and the number of doses in the vial stay the same. Draws are on a U-100 insulin syringe, where 1 unit is 0.01 mL.
| Water added | Strength | Per syringe unit | Draw for 2.5 mg |
|---|---|---|---|
| 1 mL | 5 mg/mL | 50 mcg | 50 units (0.50 mL) |
| 2 mL | 2.5 mg/mL | 25 mcg | 100 units (1.00 mL) |
| 3 mL | 1.667 mg/mL | 16.7 mcg | 1.50 mL |
Dose chart
Syringe units for each common dose at each water volume. Select a cell to open it in the calculator.
| Dose | Water added | ||
|---|---|---|---|
| 1 mL | 2 mL | 3 mL | |
| 2 mg | |||
| 2.5 mg | |||
Draws over 100 units show in mL. Faded values are under 2 units, which is hard to measure. Check that your vial holds the larger volumes.
Where the doses come from
- Trial IV infusion of 42–1,260 mg once daily for 14 days in healthy volunteers, a safety test only.
- Trial Eye drops: 0.1% solution (RGN-259) 5× daily for 28 days in neurotrophic keratitis; 2–6× daily for 2–4 weeks in dry-eye trials.
- Community No protocol specific to the full protein. Guides often treat it as the same thing as TB-500 and use that schedule: 2–2.5 mg under the skin twice weekly for 4–6 weeks, then about 2 mg weekly.
Doses are what labels, trials or community reports reference, not recommendations. Thymosin Beta-4’s page has the cycle, side effects, cautions and sources.
Mixing and storage
- PrepareLet a refrigerated vial come to room temperature, and wipe both stoppers with an alcohol swab.
- Add 1 mLDraw 1 mL of bacteriostatic water and let it run slowly down the inside wall of the vial.
- Swirl, don’t shakeSwirl gently until the powder dissolves and the liquid is clear.
- Label itWrite the date and the strength, 5 mg/mL, on the vial.
Storage: Powder: −20 °C long-term. Mixed: 2–8 °C, use within about 4 weeks.
The reconstitution guide covers each step, and the units page explains syringe markings.
Questions
How much water do I add to a 5 mg vial of thymosin beta-4?
There’s no single right amount: the water only sets the strength. With 1 mL of bacteriostatic water, a 5 mg vial holds 5 mg/mL. With 2 mL it’s 2.5 mg/mL; with 3 mL it’s 1.667 mg/mL. Less liquid makes each dose a smaller draw; more makes small doses easier to measure.
How many units is 2.5 mg of thymosin beta-4?
With 1 mL in a 5 mg vial, 2.5 mg is 50 units (0.50 mL) on a U-100 insulin syringe. With 2 mL, 100 units (1.00 mL); with 3 mL, 1.50 mL.
How many doses are in a 5 mg vial of thymosin beta-4?
About 2 doses of 2.5 mg, or 2 of 2 mg. Taken 2× per week at 2.5 mg, it lasts about 7 days.
How long does a mixed vial of thymosin beta-4 keep?
Powder: −20 °C long-term. Mixed: 2–8 °C, use within about 4 weeks.
Other vial sizes
Sources
- Ruff et al., IV thymosin beta-4 in healthy volunteers, Phase 1 (Ann N Y Acad Sci 2010) PMID 20536472
- Sosne et al., RGN-259 eye drops in neurotrophic keratopathy, SEER-1 (Int J Mol Sci 2022) PMID 36613994
- ARISE-3 dry-eye trial, posted registry results (NCT03937882)
- RegeneRx letter to stockholders on the SEER-2 trial (September 1, 2026)
- FDA briefing document: TB-500-related bulk drug substances (July 2026)
The math on this page uses the doses and storage on Thymosin Beta-4’s page.