Last updated: June 2026 · Reviewed June 2026 · Built by the InjectBuddy team
How does the peptide blend calculator work? two peptides, one vial
A peptide blend calculator works by dividing each peptide's mass by the shared bacteriostatic water volume to find its individual mg/mL concentration, then converting your target dose into a draw volume and U-100 syringe units. Because both peptides dissolve in the same water, every draw delivers a fixed proportion of each compound — you size from the one you are dosing and read the other as a passenger. This guide explains the arithmetic step by step, walks through eight worked examples, and answers the questions people ask most.
Key takeaways
- Each peptide in a blend has its own concentration = its mg ÷ the total bacteriostatic water added.
- One draw delivers both peptides at once, in the fixed ratio set when you reconstituted them.
- Pick the component you actually titrate, divide its target dose by its concentration, then ×100 for U-100 units.
- Research peptides like BPC-157 and TB-500 have no established human dose — this is arithmetic only, not a protocol.
Run your own numbers in the BPC-157 + TB-500 blend calculator after reading the worked examples below.
What a multi-peptide blend actually is
A blend is two (or more) freeze-dried peptides drawn into one vial and reconstituted together with a single volume of bacteriostatic water. Because they share the liquid, every microliter you draw contains a fixed proportion of each peptide. That makes a blend convenient — one injection, one site — but it also locks the ratio. You cannot raise one peptide without raising the other unless you mix a fresh vial at a different ratio.
Bacteriostatic water carries a 0.9% benzyl alcohol preservative that slows microbial growth across repeated punctures of a multiple-dose vial; it does not re-sterilise the vial, so clean technique still matters (Hospira DailyMed label). The amino-acid peptides themselves are delicate and many of the popular research blends have never had a human dose established in trials — the maths below is for splitting a known target accurately, not for choosing that target.
How this is calculated
Treat each peptide independently, then remember they share one draw. For a two-component blend the arithmetic is:
- Concentration of each peptide = its mass in the vial ÷ the bacteriostatic water volume. A 5 mg peptide in 2 mL is 2.5 mg/mL (2,500 mcg/mL); a 10 mg peptide in the same 2 mL is 5 mg/mL.
- Choose the dosing component — the one your protocol targets in mcg. You size the syringe from that peptide.
- Draw volume = target dose ÷ that peptide's concentration. Keep the mass units matched (mcg with mcg/mL).
- Units = draw volume in mL × 100 on a U-100 insulin syringe.
- Confirm the passenger dose — the same draw also delivers the second peptide. Multiply the draw volume by the second peptide's concentration to see how much rides along.
The passenger step is the part people skip. Once you fix the draw from peptide A, peptide B's dose is no longer a free choice — it is whatever the ratio gives. If that passenger dose is wrong for your goal, you change the vial ratio, not the syringe.
Two-component blend → units chart
Both peptides reconstituted in 2 mL of bacteriostatic water. The draw is sized from the first peptide; the second column shows what the same draw delivers as a passenger.
| Blend (in 2 mL) | Conc. A / B | Target dose A | Draw | U-100 units | Passenger dose B |
|---|---|---|---|---|---|
| 5 mg A + 5 mg B | 2,500 / 2,500 mcg/mL | 250 mcg A | 0.10 mL | 10 units | 250 mcg B |
| 10 mg A + 5 mg B | 5,000 / 2,500 mcg/mL | 500 mcg A | 0.10 mL | 10 units | 250 mcg B |
| 5 mg A + 10 mg B | 2,500 / 5,000 mcg/mL | 250 mcg A | 0.10 mL | 10 units | 500 mcg B |
| 10 mg A + 10 mg B | 5,000 / 5,000 mcg/mL | 300 mcg A | 0.06 mL | 6 units | 300 mcg B |
Notice the bottom three rows all share the same vial water but give different passenger doses — the ratio is set the moment you choose how much of each powder goes in.
Worked examples
5 mg A + 5 mg B in 2 mL. Each is 2,500 mcg/mL. Target 250 mcg of A: 250 ÷ 2,500 = 0.10 mL = 10 units. Passenger B = 0.10 × 2,500 = 250 mcg. A 1:1 blend always gives equal doses.
10 mg A + 5 mg B in 2 mL → 5,000 and 2,500 mcg/mL. Target 500 mcg A: 500 ÷ 5,000 = 0.10 mL = 10 units. Passenger B = 0.10 × 2,500 = 250 mcg, exactly half of A.
Same 10 mg A + 5 mg B vial. Now you target 250 mcg of B: 250 ÷ 2,500 = 0.10 mL = 10 units. The passenger A = 0.10 × 5,000 = 500 mcg. Whichever peptide you size from, the other follows the ratio.
10 mg A + 10 mg B in 2 mL → both 5,000 mcg/mL. Target 300 mcg A: 300 ÷ 5,000 = 0.06 mL = 6 units. Passenger B is also 300 mcg. A 6-unit mark on a 0.3 mL syringe is easy to read accurately.
Same 10 + 10 mg vial but reconstituted in 3 mL. Each peptide is now 3,333 mcg/mL. Target 300 mcg A: 300 ÷ 3,333 = 0.09 mL = 9 units. More water spreads the dose over more marks — the dose did not change, the draw did.
Target written as 0.5 mg of A in a 5,000 mcg/mL component. Convert first: 0.5 mg = 500 mcg. Then 500 ÷ 5,000 = 0.10 mL = 10 units. Forgetting the ×1,000 conversion is the fastest way to be off by a decimal place.
You want A and B both at 300 mcg per shot but your draw is fixed at 0.06 mL. That needs both at 5,000 mcg/mL, so mix 10 mg A + 10 mg B in 2 mL. To make B half of A instead, mix 10 mg A + 5 mg B — the syringe never changes, the vial does.
A 2 mL vial drawn at 0.10 mL per dose holds 2 ÷ 0.10 = 20 doses on paper. Dead space in the needle hub means real yield is slightly lower, which matters when the peptide is scarce.
Common blend mistakes
The biggest error is copying someone else's unit count. Ten units only equals your dose if your two mg amounts and your water volume match theirs exactly. A second error is forgetting the passenger: people size the draw from peptide A and never check what dose of B they are also taking. Third is mixing mg and mcg, an instant decimal-place slip. Finally, do not assume a blend is automatically the right ratio for your goal — the ratio is whatever you put in the vial, and changing it means a new vial, not a new syringe setting.
So, how does the peptide blend calculator work?
The peptide blend calculator works by finding each peptide's individual concentration (its milligrams divided by the shared water volume in milliliters), then dividing your target dose by that concentration to get the draw volume in mL, and multiplying by 100 for U-100 syringe units. The passenger dose of the second peptide is then simply the draw volume multiplied by its own concentration. Because the ratio is locked at reconstitution, the only way to change one peptide's dose independently is to mix a fresh vial. Run your exact mg amounts and water volume through the BPC-157 + TB-500 blend calculator to get draw volume and units in one step.
FAQs
How does a peptide blend calculator work?
Can I dose one peptide in a blend without affecting the other?
Which peptide do I size the syringe from?
Is a peptide blend a recommended treatment?
Does more bacteriostatic water change my dose?
Sources
- Hospira, Inc. Bacteriostatic Water for Injection, USP (0.9% benzyl alcohol) prescribing information. DailyMed label.
- CDC. Safe Injection Practices to Prevent Transmission of Infections to Patients. CDC clinical guidance.
- Manchikanti L, et al. Assessment of infection control practices for interventional techniques. Pain Physician. 2012;15(5). PMID 22996856.
- Muttenthaler M, et al. Trends in peptide drug discovery. Nat Rev Drug Discov. 2021. PMID 33536635.
This guide is for general educational purposes only and does not constitute medical advice. Research peptides such as BPC-157 and TB-500 have no established human dose; this is a maths reference only. Always follow your prescriber's specific instructions.