TB-500 5 mg reconstitution calculator
How much bac water for TB-500 5 mg?
There’s no single right amount: the water sets the strength, not how much TB-500 is in the vial, so use the volume on your pharmacy’s instructions. For example, 1 mL makes 5 mg/mL and 2 mL makes 2.5 mg/mL; the table below shows what each volume means on a U-100 syringe.
Your TB-500 vial
Syringe
1 mL · 2-unit marks
Work backwards
Find the water for a given reading in units.
Enter your numbers to see the result.
Enter your numbers
This is arithmetic, not medical advice. Confirm with your prescriber or pharmacist.
How our calculator worksAdvanced
Vial capacityOptional
The volume printed on the vial or its box, not the mg. We’ll tell you if the water won’t fit.
What each volume makes
| Water | Strength | Each unit | 1 mg is |
|---|---|---|---|
| 1 mL | 5 mg/mL | 50 mcg | 20 units |
| 2 mL | 2.5 mg/mL | 25 mcg | 40 units |
| 2.5 mL | 2 mg/mL | 20 mcg | 50 units |
Examples; use the volume on your pharmacy’s instructions. Units are on a U-100 syringe: 100 units = 1 mL.
About the 5 mg vial
TB-500 isn't thymosin beta-4
TB-500 is a synthetic seven-amino-acid fragment (Ac-LKKTETQ) of thymosin beta-4, a 43-amino-acid protein. Many websites use the two names interchangeably, but the FDA states that thymosin beta-4 and TB-500 are not the same substance (FDA briefing, 2026). That matters when you read about what’s in your vial: research on full-length thymosin beta-4 doesn’t transfer to TB-500. The arithmetic on this page works the same for any powder, from the mg printed on your label, but the two names aren’t interchangeable.
5 mg is a size sold for "research use only"
The FDA found websites offering TB-500 as 2, 3, 5, 10 and 15 mg powders for reconstitution, stating that the products are intended for research use only. No outsourcing facility has reported compounding TB-500 to the FDA, and TB-500 isn’t a component of any FDA-approved drug (FDA briefing, 2026). So the 5 mg on a vial like this is the maker’s own figure, and no regulator has checked it. The math above is only as accurate as that number.
No official standard for what's inside
There’s no USP or National Formulary monograph for TB-500 free base or TB-500 acetate, which the FDA treats as two different active ingredients. The FDA adds that specific tests for TB-500, such as tests for impurities, aggregates, microbiological quality and bacterial endotoxin, are not available in the public domain (FDA briefing, 2026). A label reading “TB-500 5 mg” may not say which form it holds. Ask a pharmacist before mixing.
Sources for these notes
- FDA Briefing Document for TB-500-Related Bulk Drug Substances (PCAC, July 23-24, 2026)U.S. Food and Drug Administration, 2026 (opens in a new tab)
- FDA Briefing Document for TB-500-Related Bulk Drug Substances (PCAC, July 23-24, 2026)U.S. Food and Drug Administration, 2026 (opens in a new tab)
- FDA Briefing Document for TB-500-Related Bulk Drug Substances (PCAC, July 23-24, 2026)U.S. Food and Drug Administration, 2026 (opens in a new tab)
About TB-500
US regulatory status
Not approved for human use in the US
TB-500 is not approved by the FDA for any use and is not the same substance as thymosin beta-4. As of April 2026 its nomination had been withdrawn from the FDA’s Category 2 safety-risk list. In July 2026 an FDA advisory committee narrowly voted, against FDA staff advice, to recommend adding it to the 503A bulks list; the vote is not binding, and as of October 16, 2026 no rule had been published. WADA bans thymosin beta-4 and its derivatives, naming TB-500, at all times (S2.3).
As of
Sources (5)
- Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksU.S. Food and Drug Administration, 2026 (opens in a new tab)
- FDA Briefing Document for TB-500-Related Bulk Drug Substances (PCAC, July 23-24, 2026)U.S. Food and Drug Administration, 2026 (opens in a new tab)
- July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory CommitteeU.S. Food and Drug Administration, 2026 (opens in a new tab)
- FDA advisers narrowly vote to add 6 peptides to a drug compounding list. What’s next?ABC News, 2026 (opens in a new tab)
- World Anti-Doping Code International Standard: Prohibited List 2026World Anti-Doping Agency, 2026 (opens in a new tab)
How this TB-500 calculator works
This TB-500 reconstitution calculator starts from the 5 mg in your vial. Add the water you mix it with and the dose your prescriber gave you; it divides the mg by the mL to get the strength, then turns your dose into mL and units on a 30, 50 or 100-unit syringe.
Peptinote never suggests a dose or a water volume. The example volumes are there to make the math easy to check, not as advice. For the full method, see the peptide calculator.
Questions people ask
How much bac water for a 5 mg TB-500 vial?
There’s no single right amount: use the volume on your pharmacy’s instructions. The water only sets the strength; the vial still holds 5 mg however much you add. With 1 mL it’s 5 mg/mL (50 mcg per unit), with 2 mL 2.5 mg/mL (25 mcg per unit) and with 2.5 mL 2 mg/mL (20 mcg per unit). Enter your volume and prescribed dose above to get the units. This product isn’t FDA-approved, so no official label sets a water volume and its contents aren’t verified.
How do I reconstitute TB-500?
Wipe both stoppers with alcohol and let them dry. Draw the volume of bacteriostatic water your pharmacy specifies into a new syringe, add it slowly down the inside of the vial, then swirl gently until clear; don’t shake. Label it with the strength: 5 mg in 1 mL is 5 mg/mL. Full steps: how to reconstitute peptides.
How do I mix TB-500?
Mixing your TB-500 5 mg vial takes the bacteriostatic water your pharmacy specifies and a new sterile syringe. Add the water slowly against the glass and swirl, never shake, until the liquid is clear. If it stays cloudy or has particles, don’t use it; call your pharmacy. Then write the strength and date on the vial and store it as the label says (how to store peptides).
Is there a TB-500 peptide calculator?
This page is the TB-500 5 mg reconstitution calculator. Enter the water you add (or tap an example volume) and your prescribed dose, and it shows the units to draw on a 30, 50 or 100-unit syringe, the strength, and the doses in the vial, with every step of the math. It never suggests a dose.
Can Peptinote tell me how many units to take?
No. Peptinote never suggests a dose. Enter the dose your prescriber gave you, and the calculator shows how to measure it: the units, the mL and where the line sits on your syringe, with every step of the math. If you aren’t sure what your dose is, ask your prescriber or pharmacist before drawing anything. How our calculator works.
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Every result is plain arithmetic from formulas we publish in full and check with automated tests. Peptinote doesn’t suggest doses and never sells or links to sellers of peptides.