How to reconstitute TB-500

Before you start

TB-500 has no official preparation standard: there is no USP or National Formulary monograph, and it is not part of any approved drug.¹ The solubility and storage figures on this page are vendor and public data that FDA cited in its 2026 review.¹ Because FDA has seen other salts and molecules sold as TB-500, check the lot's certificate of analysis before mixing.¹ It should report a mass near 889 g/mol, the value PubChem gives for TB-500.² The acetate salt is heavier, at 949.1 g/mol.¹ Vial sizes also vary: the websites FDA found sold 2 to 15 mg vials, so read the label before doing the math.¹

This page covers lab handling only. It does not give instructions for injecting TB-500.

Supplies

These supplies are listed with the TB-500 vial in this store:

• Bacteriostatic water, the diluent paired with the vial
• 3 mL Luer-Lok syringe and 18G 1-inch needle, for measuring and adding the diluent
• Insulin syringes, for measuring small volumes of the solution
• Alcohol swabs, for wiping vial stoppers

Vendor data cited by FDA describe TB-500 free base as a white to off-white solid that dissolves in water at 50 mg per mL.¹ Bacteriostatic water is sterile water with 0.9% or 1.1% benzyl alcohol as a preservative, in a multiple-dose container from which repeated withdrawals may be made.⁵ Plain sterile water has no preservative and comes only in single-dose containers.⁶ The bacteriostatic water label warns that some drugs may be incompatible with benzyl alcohol.⁵

Steps in the lab

1. Plan the concentration. Choose the diluent volume from the table below, or use the reconstitution calculator.
2. Prepare the work area. Work in a clean area away from sinks, with alcohol wipes and sterile syringes and needles at hand.⁸ Wipe each rubber stopper with an alcohol swab. The bacteriostatic water label calls for aseptic technique for every entry into and withdrawal from a container.⁵
3. Add the diluent. Draw the planned volume into the 3 mL syringe and add it to the powder vial. The ZOMACTON (somatropin) label, for example, says to aim the stream against the side of the vial to prevent foaming, then swirl gently and not shake.⁷
4. Check that it dissolved. At 50 mg per mL, solubility does not limit any volume in the table.¹ The bacteriostatic water label says to inspect a reconstituted solution for clarity, precipitation or discoloration.⁵ FDA notes that pH, heat, concentration, impurities and added ingredients can make peptides like TB-500 aggregate or degrade.¹
5. Label and store. Mark the vial with the date, the diluent volume and the concentration, then store it as shown below. Record the lot number too, so results can be matched to the lot's certificate of analysis later.

The general reconstitution guide explains each step for any peptide vial.

Concentration math

Concentration (mg/mL) = peptide in the vial (mg) ÷ diluent added (mL). To find the volume that holds a set amount, divide the amount (mg) by the concentration (mg/mL).

For a 5 mg vial:

Worked example: adding 2 mL to a 5 mg vial gives 5 ÷ 2 = 2.5 mg/mL. A 0.5 mg sample of that solution sits in 0.5 ÷ 2.5 = 0.2 mL. The units converter turns milliliters into insulin-syringe units, and the peptide calculator handles other vial sizes.

Salt form changes the math slightly. TB-500 free base is 889.0 g/mol and the acetate is 949.1 g/mol.²¹ If a vial's 5 mg is weighed as the acetate, it holds 5 × 889.0 ÷ 949.1 = 4.68 mg of free base. Concentrations then run about 6% below the table. The certificate of analysis should state which form was weighed.

Storage before and after mixing

The data sheet calls for a sealed container kept away from moisture and light, under nitrogen.¹ Mixing shortens storage life sharply: at -20°C, the solution keeps 1 month against 1 year for the powder.¹ For a vial of diluent, CDC guidance is to date a multiple-dose vial once it is opened and discard it within 28 days unless its maker states another date.⁸ More storage guidance is in how to store peptides.

TB-500 injection site: what studies used

No controlled study has tested a TB-500 injection site in people; FDA found no clinical studies or human exposure data by any route.¹ Published work used these routes:

• Rats: injection into the abdominal cavity (intraperitoneal), daily for 4 weeks after tendon repair or once for a metabolism study.³¹
• Horses: one injection under the skin (subcutaneous) for drug-testing research.¹
• People: in the uncontrolled 2026 case series, 3 patients received the TB-500 mix as localized injections under the lining of the mouth (intraoral submucosal).⁴

The withdrawn compounding nomination that FDA reviewed proposed injection under the skin and into muscle.¹ In FDA's general assessment, subcutaneous routes carry more immunogenicity than intramuscular or intravenous ones.¹ Sharps disposal and how prescribed injectable medicines are given are covered in the injection guide.

Related pages

The overview is in What is TB-500?. Study doses are on TB-500 dosage, safety data on TB-500 side effects, and reported results on TB-500 benefits and uses. The research vial and its listed supplies are under TB-500 for sale.