How to reconstitute peptides (and use the calculator)

There's no single 'correct' amount — more water makes a more dilute solution that's easier to measure but means a larger injection volume. A common approach is to pick the water volume that puts your usual dose on an easy-to-read mark (like 10, 20 or 25 units). Use the calculator's 'Solve: water' mode: enter your vial size, your dose, and the units you'd like to draw, and it returns the water volume.

Peptides are almost always drawn with U-100 insulin syringes, which are marked in 'units' where 100 units = 1 mL. Telling you '12.5 units' is directly readable on the syringe, whereas '0.125 mL' would force you to convert. The calculator shows both the units and the underlying volume in mL.

1 mg = 1000 mcg. GLP-1 medications like semaglutide and tirzepatide are dosed in milligrams (mg); most research peptides like BPC-157 and ipamorelin are dosed in micrograms (mcg). Mixing these up is a 1000× error, so the calculator makes you choose the unit explicitly and shows the concentration so an unreasonable answer stands out.

Very small volumes are hard to measure accurately on a U-100 syringe. If your result is under about 3 units, add less bacteriostatic water (a more concentrated solution) so the same dose draws to a larger, easier-to-read mark. The calculator flags this and the 'Solve: water' mode helps you fix it.

Once mixed with bacteriostatic water and refrigerated, many peptides remain stable for several weeks — the benzyl alcohol in BAC water is a preservative that allows multiple draws. Exact stability varies by compound and supplier; follow the guidance from your source and provider.

Shaking forces air through the solution and creates foam and shear forces that can denature (unfold) or aggregate fragile peptide chains, potentially reducing potency. A few accidental shakes usually won't ruin a robust peptide, but it's not worth the risk — swirl or gently roll the vial between your palms instead, and let any foam settle before drawing. If the solution turns persistently cloudy, stays foamy, or shows floating particles after settling, don't use it.

For a single-use, draw-it-all-at-once situation, sterile water will dissolve the powder, but it has no preservative, so it isn't suited to a multi-dose vial you'll draw from over days or weeks. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and is why a reconstituted vial can be used for multiple draws. Most people use bacteriostatic water for that reason.

Yes — wipe the rubber stopper with a fresh alcohol swab before each needle insertion. The stopper is touched, exposed to air, and re-pierced repeatedly, so swabbing each time reduces the chance of introducing bacteria into a vial you'll keep for weeks.

Store the reconstituted vial in the refrigerator (roughly 2–8°C / 36–46°F) and keep it out of light. Avoid the freezer once it's mixed — a freeze-thaw cycle can damage many peptides. Unmixed lyophilized powder is much more stable and is often kept frozen before reconstitution; follow your supplier's guidance.

A little residue that dissolves once the water washes over it is normal. Add the water slowly down the inside wall and swirl gently until the solution is completely clear with nothing undissolved. If clumps or particles remain after gentle swirling, don't force it by shaking — give it time, and discard the vial if it won't fully dissolve.

A bubble takes up space where liquid should be, so it can make you under-dose. Tap the syringe so the bubble rises to the needle, push it out, then re-draw to your target unit mark. Always set the dose by the liquid level at your mark, not by where a bubble sits.