How to reconstitute a peptide vial without screwing it up

Reconstitution is the step where you turn a vial of dry peptide powder into an injectable liquid. Done wrong, you waste expensive product or contaminate the vial.

What you need: the peptide vial, bacteriostatic water (BAC water), an alcohol swab, a 3mL syringe with a 21G drawing needle (or just the insulin needle if you are careful), a clean flat surface.

Step 1. Wipe both vial tops with alcohol. Let them air dry for 10 seconds.

Step 2. Draw the BAC water into the syringe. The amount you draw depends on the math you did beforehand. The Calculator tab handles this for you.

Step 3. Insert the needle into the BAC water vial at an angle, pull air out first if there is pressure, then pull your target water volume.

Step 4. Inject the BAC water into the peptide vial slowly, aiming the stream at the side of the glass, not directly onto the powder. Hitting the powder head-on causes foaming, which damages peptide structure.

Step 5. Do not shake. Swirl gently. The powder dissolves in 30 to 60 seconds.

Step 6. Refrigerate immediately. Most peptides keep 2-4 weeks reconstituted at fridge temp. BPC-157, TB-500, and GHK-Cu hold well. GLP / GIP class drugs (semaglutide, tirzepatide, retatrutide) hold up to 4-6 weeks. Always check the specific peptide.

Common mistakes: foaming the powder by spraying water directly at it, leaving the reconstituted vial at room temp overnight, double-dipping a used insulin needle into the vial.

For sub-q injection (the default for most peptides)

The standard process above. BAC water (with 0.9% benzyl alcohol preservative) is the diluent. Use a 1mL insulin syringe with a 29-31 gauge needle. Concentrations are calibrated for clean syringe-unit math (see the Calculator).

For intramuscular (IM) injection

Same reconstitution, different injection setup. IM goes deeper into muscle, not the fat layer. Sometimes used for TB-500 (loading phase) and certain GH-axis peptides where the larger depot helps absorption pacing. Use a 23-25 gauge needle, 1-1.5 inches long. Standard sites: outer deltoid, vastus lateralis (outer thigh), gluteus medius (upper outer butt). Slower injection than sub-q, gentle aspiration to verify you're not in a vessel.

For intranasal sprays (Selank, Semax, Oxytocin, MT-1/2 in some protocols, VIP)

Reconstitution rules change. Two key differences:

1. The diluent is usually saline + benzalkonium chloride (BAK), not standard BAC water. BAK keeps the spray bottle from growing bacteria across multiple uses. Some users substitute BAC water plus a few drops of glycerin; the longer-storage versions use BAK. 2. You're transferring from the vial into a metered nasal spray bottle (typically 100 mcL per pump). Calculate dose-per-pump backward from desired dose: dose ÷ pumps-per-dose = mcg per pump.

Process: reconstitute the peptide in the vial as normal with the appropriate diluent, then draw the full reconstituted volume out and inject it into the empty sterilized nasal spray bottle. Prime the bottle (3-5 pumps into a tissue) before first use.

For oral peptides (BPC-157 oral, MK-677, 5-Amino-1MQ, Dihexa)

No reconstitution needed for the small-molecule oral capsules (MK-677, 5-Amino-1MQ). For oral BPC-157, some protocols call for sub-lingual administration of the reconstituted liquid, same reconstitution as sub-q, but you place the dose under your tongue and hold for 30-60 seconds before swallowing.

Storage by route

Reconstituted vials and prepared spray bottles all go in the fridge. Nasal sprays specifically: keep upright, away from light. Don't carry the spray bottle around in a warm pocket.