Free tool
Peptide dosage
calculator.
Vial, bacteriostatic water, dose — exact insulin syringe units. Presets for 17 peptides, mcg and mg, remembers your numbers. Runs on your device, no signup.
Pick your peptide or type any numbers below.
10 units
draw to 10 units50 u
Volume to draw0.1 ml
Concentration2500 mcg per ml
Vial lasts20 doses
Dose exceeds this syringe — add less water or use a bigger syringe.
The Reconstitution Card, free PDFEight peptides, doses and units on one printable page — keep it next to the vials
Download the card
How the math works
Reconstitution is one formula. The concentration of your vial is the peptide amount divided by the water you added. The volume you draw is your dose divided by that concentration.
On a U-100 insulin syringe, one full milliliter equals 100 units. So 0.1 ml is 10 units, 0.05 ml is 5 units. The calculator does this conversion for you.
Worked example
A 5 mg vial of BPC-157 with 2 ml of bacteriostatic water gives 2500 mcg per ml. A 250 mcg dose is 0.1 ml — 10 units on any insulin syringe. The vial holds 20 such doses.
Mixing in five steps
1. Wipe both vial tops with an alcohol swab
The peptide vial and the bacteriostatic water vial both have rubber stoppers. Let them dry for a few seconds.
2. Draw the water you planned
Use the ml number you entered above. A larger mixing syringe with a bigger needle makes this step easier than an insulin syringe.
3. Let the water run down the glass wall
Tilt the peptide vial and let the stream slide down the inside wall. Never spray directly onto the powder — the pressure can damage fragile peptides.
4. Swirl gently, never shake
Roll the vial slowly between your fingers until the solution is clear. Most peptides dissolve within a couple of minutes.
5. Refrigerate and date the vial
Reconstituted peptides live in the fridge. Write the date on the label — with bacteriostatic water most solutions are used within three to four weeks.
A prescription peptide from a licensed pharmacy arrives with dosing set by your doctor. This tool is for understanding the math, not for choosing your own dose.
Common mixes at a glance
Tap any row to load it into the calculator.
| Vial | Water | Concentration | Common dose | Units |
|---|---|---|---|---|
| 5 mg | 2 ml | 2500 mcg per ml | 250 mcg | 10 u |
| 5 mg | 2.5 ml | 2000 mcg per ml | 300 mcg | 15 u |
| 10 mg | 2 ml | 5000 mcg per ml | 1 mg | 20 u |
| 10 mg | 2 ml | 5000 mcg per ml | 2.5 mg | 50 u |
| 10 mg | 2.5 ml | 4000 mcg per ml | 2.5 mg | 62.5 u |
| 15 mg | 2 ml | 7500 mcg per ml | 5 mg | 66.7 u |
| 30 mg | 3 ml | 10 000 mcg per ml | 2.5 mg | 25 u |
| 50 mg | 5 ml | 10 000 mcg per ml | 2 mg | 20 u |
Common questions
How much bacteriostatic water do you mix with peptides?
Common practice is 1 to 3 ml per vial. More water means larger, easier-to-measure syringe volumes at the same dose; the total peptide in the vial is unchanged. Pick a volume that puts your dose between 5 and 50 units on your syringe.
What is 0.25 mg in units on an insulin syringe?
0.25 mg is 250 mcg. With a 5 mg vial and 2 ml of water the concentration is 2500 mcg per ml, so 250 mcg is 0.1 ml — 10 units on any U-100 syringe. With different vial or water amounts the answer changes; enter your numbers above.
How long does a reconstituted peptide last in the fridge?
With bacteriostatic water, common practice is three to four weeks refrigerated. With plain sterile water the vial should be used within days. Your pharmacy label overrides any general rule.
Bacteriostatic water or sterile water — which one?
Bacteriostatic water contains 0.9% benzyl alcohol, which keeps a multi-dose vial usable for weeks. Plain sterile water has no preservative and is only for single immediate use. Multi-dose peptide vials need bacteriostatic.
What are common mistakes in peptide reconstitution?
Confusing mg with mcg is the big one — a thousandfold error. The others: using plain sterile water for multi-dose vials, spraying water directly onto the powder instead of down the vial wall, and shaking the vial instead of swirling it gently.
How do I reconstitute 30 mg of peptide?
The formula is identical at any size: 30 mg is 30 000 mcg. With 3 ml of water the concentration is 10 000 mcg per ml, so a 2.5 mg dose is 0.25 ml — 25 units. Tap the 30 mg row in the table above and the calculator adjusts everything.
Which insulin syringe size should I get?
The 0.5 ml U-100 syringe with a 30 or 31 gauge needle covers most peptide doses. Pick 0.3 ml if your doses land under 15 units — the tighter scale is easier to read. The 1 ml size is for larger volumes like NAD+.
Can I mix two peptides in one syringe?
Clinics dispense combined vials — CJC-1295 with ipamorelin is the common one — already blended by the pharmacy. Do not combine separate products yourself unless your pharmacy instructs it.
Does the calculator work for semaglutide and tirzepatide?
The math is the same for any lyophilized compound. Note that FDA-approved GLP-1 medicines come in pre-filled pens with fixed dosing — you only reconstitute compounded versions, which your pharmacy will instruct you on.
Why are peptide doses measured in units?
Units are just the scale printed on insulin syringes: 100 units equal 1 ml on a U-100 syringe. Doses are prescribed in mcg or mg; units are how you find that dose on the syringe barrel.
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Dosing is the easy part.
Whether a peptide is right for you at all is a physician's call. That consultation is cheaper than one wasted vial.
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