How peptide reconstitution works
Lyophilised (freeze-dried) peptides arrive as a powder. You dissolve them in bacteriostatic water (BAC water) before use — this is reconstitution. The amount of water you add sets the concentration: more water = lower concentration and larger draw volume per dose; less water = higher concentration and smaller draw. There is no single correct volume — you choose based on what gives you a comfortable, accurate draw.
Reading a U-100 syringe
A U-100 insulin syringe holds exactly 1 mL, divided into 100 equal units. One unit equals 0.01 mL. To convert: multiply your mL draw volume by 100. This calculator does it automatically and shows the mark on the visual syringe above — so you can confirm the position before drawing your dose.
Choosing the right water amount
A good target is a draw volume between 5 and 50 units (0.05–0.50 mL). Below 5 units, small measurement errors become a large percentage of your dose. Above 50 units, you're drawing more than half a syringe, which is manageable but less precise. Adjust BAC water volume until your unit mark lands in that window.
Common peptides at a glance
| Peptide | Typical vial | Typical dose |
|---|---|---|
| BPC-157 | 5 mg | 250–500 mcg |
| TB-500 | 10 mg | 2,000–5,000 mcg |
| CJC-1295 | 2 mg | 100–200 mcg |
| Ipamorelin | 5 mg | 200–300 mcg |
| Semaglutide | 5 mg | 250–2,400 mcg |
| Tesamorelin | 2 mg | 1,000–2,000 mcg |
Storing reconstituted peptides
Once dissolved in BAC water, refrigerate at 2–8°C (36–46°F), away from light. Most reconstituted peptides remain stable for 4–6 weeks. Never freeze a reconstituted solution — freeze-thaw cycles degrade the peptide. Use bacteriostatic water (not sterile water) specifically because it inhibits bacterial growth during refrigerated storage.
Common questions
How do I reconstitute a peptide step by step?
Draw the BAC water volume into a syringe. Insert the needle through the vial's stopper and angle it so the water runs down the inner glass wall — don't squirt directly onto the powder. Inject slowly, then swirl gently until dissolved. Never shake. The solution should be clear; discard if cloudy or if particles remain.
How many units do I draw on a U-100 syringe?
Units = mL × 100. This calculator works it out and shows the exact mark on the visual syringe above, so you can confirm the draw position visually before loading the dose.
Can I use bacteriostatic saline instead of BAC water?
Bacteriostatic saline (0.9% NaCl + benzyl alcohol) works for many peptides and is sometimes preferred for nasal or inhalation delivery. BAC water (sterile water + benzyl alcohol) is most common for subcutaneous injection. The math in this calculator is identical regardless of which diluent you use.
What happens if I add too much BAC water?
Your concentration drops and the draw volume per dose increases. If the calculator shows more than 80–100 units, reconstitute with less BAC water to bring the draw into a more accurate range. The calculator will show a warning when your draw exceeds 100 units (the syringe's full capacity).
Is this the same as a peptide mixing ratio calculator?
Yes — reconstitution, mixing ratio, and dilution all describe the same step: dissolving the powder in a diluent. Vial size (mg) ÷ BAC water (mL) = concentration (mg/mL). All other outputs follow from that single number.