Free Peptide
Calculator
Surgical-grade computational tools for reconstitution, dosing, and schedule planning. Built for researchers and biohackers.
New to peptides? Read our Therapeutic Peptides Guide or the BPC-157 Dosage Guide first.
Determine precise dilution ratios for lyophilized peptides. Calculate MCG per unit based on vial volume, solvent amount, and syringe type.
Ask complex questions about dosing, reconstitution, storage protocols, or chemical properties. Get personalized recommendations based on your goals.
Visualize plasma concentration over time. Map peaks and troughs based on specific peptide half-life data to optimize research intervals.
Compare split-dosing frequencies (ED vs EOD vs 5/2). Export schedule maps for precise protocol adherence and administrative tracking.
Why Use These Tools?
In peptide research, margin of error can compromise entire protocols. Our tools provide the surgical precision required for accurate reconstitution and dosing.
Volumetric Integrity
Algorithms cross-checked against USP standards for accurate molar concentration calculations.
Dynamic Modeling
Real-time visualization of drug accumulation curves, peak/trough levels, and bio-availability over time.
Research-Grade
Supports all research peptides — BPC-157, TB-500, Semaglutide, Tirzepatide, Retatrutide, and more.
How These Tools Work
01What Is a Peptide Calculator?
A peptide calculator helps researchers work out reconstitution ratios, dose volumes, half-life accumulation, and injection schedules. If you've ever stared at a vial of lyophilized BPC-157 wondering how much water to add, that's exactly what these tools solve.
A 5mg vial reconstituted with 2mL of BAC water gives you a very different concentration than the same vial with 1mL — and that changes every single dose.
02Reconstitution Calculator
Enter your peptide amount (mg), bacteriostatic water volume (mL), and target dose (mcg). It outputs concentration per mL, volume to draw per dose, and insulin syringe units.
Works for BPC-157, TB-500, GHK-Cu, CJC-1295, Ipamorelin, Retatrutide, Semaglutide, Tirzepatide — anything in lyophilized form.
03Half-Life & Drug Accumulation
Designed for GLP-1 medications with long half-lives — Semaglutide (~7 days), Tirzepatide (~5 days), Retatrutide (~6 days). The drug accumulates over multiple doses before reaching steady state.
Most people don't realize their effective drug level at week 6 is significantly higher than after their first injection. The calculator visualizes exactly what's happening.
04Microdosing & Split Dosing
Some researchers split their weekly GLP-1 dose across 2–3 injections to reduce peak-trough swings. This can reduce side effects (especially nausea) while maintaining steadier blood levels.
Compare once-weekly vs 2× or 3× weekly dosing. See peak reduction percentages, trough levels, and optimal injection days.
How to Reconstitute Peptides
Reconstitution is the process of dissolving lyophilized (freeze-dried) peptide powder into a liquid solution using bacteriostatic water. Getting this right is critical for accurate dosing. Follow these steps every time you open a new vial.
Prepare your workspace
Gather your peptide vial, bacteriostatic water (BAC water), 70% isopropyl alcohol swabs, and an insulin syringe. Work on a clean, flat surface with good lighting.
Sanitize the vials
Wipe the rubber stoppers of both the peptide vial and the BAC water vial with alcohol swabs. Let them air dry for 10 seconds before puncturing.
Draw the bacteriostatic water
Using your peptide calculator results, draw the exact amount of BAC water into the syringe. Common ratios: 1mL per 5mg of peptide, though this varies — use our calculator above for your specific peptide.
Inject water into the peptide vial
Insert the needle through the rubber stopper and slowly inject the BAC water. Aim the stream at the glass wall of the vial, not directly onto the peptide powder. This prevents foaming and potential damage to the peptide structure.
Dissolve gently
Roll the vial between your palms for 30-60 seconds until the powder is completely dissolved and the solution is clear. Never shake the vial — shaking can cause denaturation and reduce potency.
Store and label
Store the reconstituted peptide upright in the refrigerator at 2-8°C (36-46°F). Label the vial with the reconstitution date. Most peptides remain stable for 28-30 days after reconstitution with BAC water.
How Much Bacteriostatic Water to Add
The amount of BAC water determines your solution concentration, which affects how much liquid you draw per dose. More water means a more dilute solution (easier to measure small doses), while less water keeps injection volumes small. Here are common reconstitution ratios used for popular peptides:
| Peptide | Vial Size | BAC Water | Concentration | Typical Dose |
| BPC-157 | 5mg | 1mL | 5mg/mL | 250-500 mcg/day |
| TB-500 | 5mg | 1mL | 5mg/mL | 2-2.5mg 2x/week |
| CJC-1295 (No DAC) | 5mg | 2mL | 2.5mg/mL | 100-300 mcg/day |
| Ipamorelin | 5mg | 2mL | 2.5mg/mL | 200-300 mcg 2-3x/day |
| Semaglutide | 5mg | 2mL | 2.5mg/mL | 0.25-2.4mg/week |
| Tesamorelin | 5mg | 2.5mL | 2mg/mL | 1-2mg/day |
| PT-141 | 10mg | 3mL | 3.33mg/mL | 500-1750 mcg as needed |
| GHK-Cu | 50mg | 3mL | 16.7mg/mL | 1-2mg/day |
| MOTS-c | 10mg | 2mL | 5mg/mL | 200-1000 mcg/day |
| Retatrutide | 10mg | 2mL | 5mg/mL | 1-12mg/week |
These are common reconstitution ratios. Use the peptide calculator above with your specific vial size and desired dose for exact measurements.
Syringe Unit Conversion Chart
On a U-100 insulin syringe, 100 units = 1mL. Use this chart to quickly convert your peptide dose to syringe units at common concentrations:
| Dose | @ 2.5mg/mL | @ 5mg/mL | @ 10mg/mL |
| 100 mcg | 4 units | 2 units | 1 unit |
| 250 mcg | 10 units | 5 units | 2.5 units |
| 500 mcg | 20 units | 10 units | 5 units |
| 1mg | 40 units | 20 units | 10 units |
| 2mg | 80 units | 40 units | 20 units |
| 2.5mg | 100 units | 50 units | 25 units |
| 5mg | overflow | 100 units | 50 units |
Values over 100 units exceed a standard 1mL insulin syringe capacity. Use more BAC water to dilute the solution, or switch to a larger syringe.
Frequently Asked Questions
01How much bacteriostatic water do I add to a peptide vial?
It depends on your target dose and how concentrated you want the solution. A common approach: add 1mL of BAC water per 5mg of peptide. So a 5mg vial gets 1mL (5mg/mL), a 10mg vial gets 2mL (5mg/mL). For peptides with very small doses like BPC-157 at 250mcg, some prefer 2mL for easier syringe measurement.
02What is a peptide reconstitution calculator?
A peptide reconstitution calculator is a tool that tells you exactly how much bacteriostatic water to add to a lyophilized peptide vial and how much solution to draw for each dose. It eliminates manual math errors when converting between milligrams, milliliters, and insulin syringe units.
03What syringe do I use for peptide injections?
Standard U-100 insulin syringes — 29 to 31 gauge, 0.5mL or 1mL capacity. The 100-unit markings correspond to 1mL total volume. These are available at most pharmacies without a prescription.
04How do I convert mcg to units on an insulin syringe?
Divide your target dose in mcg by the concentration (mcg per mL) to get mL, then multiply by 100 to get insulin syringe units. For example: 250mcg dose at 5mg/mL concentration = 0.05mL = 5 units. Our peptide calculator does this automatically.
05How long does a reconstituted peptide last?
When reconstituted with bacteriostatic water (BAC water) and stored in the refrigerator at 2–8°C (36–46°F), most peptides remain stable for 28–30 days. Never freeze a reconstituted solution. Lyophilized (unreconstituted) peptides can be stored at -20°C for months.
06What is bacteriostatic water?
Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth, allowing multi-dose use from a single reconstituted vial over several weeks. Do not use plain sterile water for multi-dose vials — it has no preservative.
07Can this peptide calculator be used for GLP-1 medications?
Yes. The reconstitution calculator works for any lyophilized compound including compounded Semaglutide, Tirzepatide, and Retatrutide. The half-life and microdosing calculators are specifically designed for GLP-1 medications with long half-lives.
08How do I calculate peptide dosage by body weight?
Some peptides like BPC-157 are dosed at 1-10 mcg per kg of body weight. Multiply your weight in kg by the mcg/kg dose. For example: 80kg × 5mcg/kg = 400mcg per injection. Then use the reconstitution calculator to find how many units to draw.
09What is the difference between subcutaneous and intramuscular injection?
Subcutaneous (SubQ) injections go into the fat layer under the skin, typically in the abdomen or thigh. Intramuscular (IM) injections go into muscle tissue. Most research peptides use SubQ with a 29-31 gauge insulin syringe at a 45-degree angle.
10How do I store reconstituted peptides?
Store reconstituted peptides in the refrigerator at 2–8°C (36–46°F) in a dark environment. Keep the rubber stopper wiped with an alcohol swab before each draw. Most peptides are stable for 28-30 days after reconstitution with BAC water.
11Are these peptide calculator tools accurate?
The calculations are based on straightforward pharmacokinetic math and standard unit conversions. All results are for research and educational purposes. Always verify dosing with a healthcare provider before making any decisions.
12What size needle for peptide injections?
For subcutaneous peptide injections, use 29-31 gauge needles with 0.5 inch length. These are thin enough to minimize discomfort while being appropriate for SubQ fat layer depth. Most insulin syringes come with attached needles in this range.
The Only Peptide Calculator You Need
Our peptide calculator suite covers every step of the research workflow — from reconstituting a lyophilized vial to planning multi-week dosing protocols. Whether you're working with BPC-157, Semaglutide, Tirzepatide, or any other research compound, these tools give you the precision that manual math cannot.
A good peptide calculator does more than simple division. It accounts for real-world variables: syringe type (U-100 insulin), vial sizes ranging from 2mg to 30mg, bacteriostatic water volumes, and the specific dose you need per administration. Our reconstitution calculator handles all of this instantly, with a visual syringe readout so you can confirm the correct tick mark before every draw.
For longer protocols involving GLP-1 receptor agonists, the peptide calculator becomes even more critical. Compounds like Semaglutide (half-life ~7 days) and Tirzepatide (half-life ~5 days) accumulate significantly over weeks of dosing. Our half-life calculator models this accumulation curve so you can see your true steady-state levels — not just the dose you injected today.
Every peptide calculator on PeptideDeck is free, requires no signup, and works on any device. Bookmark this page and use it every time you reconstitute a new vial or adjust a research protocol.
All tools are for research and educational purposes only. Not medical advice.