Peptide Reconstitution Calculator (GLP-1)

Medically reviewed by FormBlends Medical Team) Board-Certified Obesity Medicine, 12+ years clinical experience

Getting your peptide dose right starts with proper reconstitution math. A peptide reconstitution calculator online takes the guesswork out of mixing your medication. Enter your vial size, the amount of bacteriostatic water you add, and your prescribed dose. The calculator tells you exactly how many units to draw on your syringe.

Key Takeaways: - Learn how peptide reconstitution works - Using the Calculator: Step by Step - Common Reconstitution Scenarios - Tips for Accurate Dosing

This isn't optional math. Getting it wrong means getting the wrong dose. Too little and your protocol may not work. Too much and you risk side effects. Let the calculator handle the numbers so you can focus on your health.

How Peptide Reconstitution Works

Reconstitution is the process of adding liquid to a freeze-dried (lyophilized) peptide powder. Most peptides arrive as a dry powder in a sealed vial. You add a specific amount of bacteriostatic water to create an injectable solution.

The concentration of your solution depends on two things: the amount of peptide in the vial (measured in milligrams) and the amount of water you add (measured in milliliters). A 5mg vial mixed with 2mL of water creates a different concentration than the same vial mixed with 1mL.

Here is a simple example. You have a 5mg vial of BPC-157. You add 2mL of bacteriostatic water. This gives you a concentration of 2.5mg per mL. If your prescribed dose is 250mcg (0.25mg), you need to draw 10 units on a standard insulin syringe.

The math is straightforward but easy to mess up with different vial sizes and dose requirements. That's why our reconstitution calculator exists. It handles every combination automatically.

"The conversation about obesity needs to shift from willpower to biology. These medications work because obesity is a neuroendocrine disease, not a character flaw.", Dr. Fatima Cody Stanford, MD, MPH, Massachusetts General Hospital

When adding water to your vial, always inject slowly along the side of the glass. Never squirt directly onto the powder. Gently swirl the vial until the powder dissolves completely. Don't shake it, as this can damage the peptide structure.

Free Download: Dose Conversion Table A quick-reference chart covering common peptide vial sizes, water volumes, and syringe measurements. Print it and keep it near your supplies. Get yours free (we'll email it to you instantly.

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Using the Calculator: Step by Step

Our peptide reconstitution calculator works with any peptide, any vial size, and any water volume. Here is how to use it.

Step 1^[1]: Enter your vial size. This is the total amount of peptide in the vial, measured in milligrams (mg). Common sizes include 2mg, 5mg, 10mg, and 15mg. Check the label on your vial or your prescription paperwork.

Step 2: Enter the water volume. This is how much bacteriostatic water you'll add, measured in milliliters (mL). Your provider or pharmacist will specify this amount. Common volumes are 1mL, 2mL, and 3mL.

Step 3: Enter your prescribed dose. This is the amount of peptide you need per injection, usually measured in micrograms (mcg). Your provider sets this number based on your protocol. For example, a common BPC-157 dose is 250mcg twice daily.

Step 4: Read your result. The calculator shows you exactly how many units to draw on your insulin syringe. It also displays a visual syringe diagram so you can see the exact fill line. No guessing required.

If you're working with multiple peptides in a stacking protocol, run the calculator separately for each one. Different peptides have different vial sizes and dosing requirements.

Try our free peptide reconstitution calculator right now) no signup required.

Common Reconstitution Scenarios

Different peptides come in different vial sizes. Here are the most common setups you'll encounter.

BPC-157 typically comes in 5mg vials. Adding 2mL of bacteriostatic water gives you 2.5mg/mL. For a 250mcg dose, draw 10 units on your syringe. For a 500mcg dose, draw 20 units.

TB-500 often comes in 5mg or 10mg vials. With a 10mg vial and 2mL of water, you get 5mg/mL. A common 2.5mg dose would be 50 units on your syringe. This is a large volume, so some people prefer adding less water for a more concentrated solution.

CJC-1295 and Ipamorelin are frequently dosed together. CJC-1295 typically comes in 2mg or 5mg vials. Ipamorelin comes in similar sizes. Each gets its own reconstitution and its own syringe draw. Check your provider's protocol for specific dosing instructions.

Semaglutide in vial form requires the same reconstitution process. The math works identically. Enter your vial size and water volume into the calculator, and it handles the rest.

Always store reconstituted peptides in the refrigerator. Most reconstituted peptides remain stable for 4 to 6 weeks when stored properly at 36 to 46 degrees Fahrenheit. Never freeze reconstituted peptides.

For a deeper look at reconstitution technique, read our complete peptide reconstitution guide.

Tips for Accurate Dosing

Precision matters when working with peptides. Small errors in measurement can lead to inconsistent results. Here are practical tips for getting it right every time.

Use insulin syringes with clear markings. A standard U-100 insulin syringe has 100 units per 1mL. The markings are fine enough for accurate peptide dosing. Most peptide doses fall between 5 and 50 units on these syringes.

Draw slowly and check for air bubbles. Air bubbles take up space in the syringe and reduce your actual dose. After drawing, tap the syringe gently with your finger to move bubbles to the top. Push them out before injecting.

Keep a dosing log. Track the date, time, peptide name, and dose for every injection. The FormBlends app makes this easy with built-in dose logging and medication level tracking. Consistent tracking helps you and your provider monitor your progress.

Never reuse needles or syringes. Each injection gets a fresh syringe. This protects against contamination and ensures accurate measurements. Used needles become dull and can cause unnecessary discomfort.

Frequently Asked Questions

How much bacteriostatic water should I add to my peptide vial?

Your provider or pharmacist will specify the exact amount. Common volumes are 1mL or 2mL for most peptide vials. Adding more water creates a more dilute solution, which means drawing more units per dose. Adding less water creates a more concentrated solution.

Can I use regular sterile water instead of bacteriostatic water?

Bacteriostatic water contains a small amount of benzyl alcohol that prevents bacterial growth. If you use plain sterile water, you must use the entire vial within a few days. Bacteriostatic water allows the reconstituted peptide to last 4 to 6 weeks in the refrigerator.

What if I add the wrong amount of water to my vial?

Don't panic. The calculator can account for any water volume. Simply enter the actual amount of water you added, and the calculator will show you the correct number of units to draw for your prescribed dose. The peptide amount in the vial doesn't change.

How do I convert between mcg and mg for peptide dosing?

There are 1,000 micrograms (mcg) in 1 milligram (mg). So 250mcg equals 0.25mg, and 500mcg equals 0.5mg. Our calculator accepts both units so you can enter your dose however your provider wrote it.

Do I need a different calculator for each peptide?

No. Our reconstitution calculator works universally with any peptide. The math is the same regardless of the peptide type. Just enter the correct vial size, water volume, and prescribed dose for each specific peptide.

What's Your Next Move?

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Sources &. References

1. Stierman B, Afful J, Carroll MD, et al. National Health and Nutrition Examination Survey 2017-March 2020 Prepandemic Data Files. NCHS Data Brief. No. 492. CDC/NCHS. 2023.
2. Sumithran P, Prendergast LA, Delbridge E, et al. Long-Term Persistence of Hormonal Adaptations to Weight Loss. N Engl J Med. 2011;365(17):1597-1604. Doi:10.1056/NEJMoa1105816
3. Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384(11):989-1002. Doi:10.1056/NEJMoa2032183
4. Davies M, Færch L, Jeppesen OK, et al. Semaglutide 2.4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2 (Davies et al., Lancet, 2021)). Lancet. 2021;397(10278):971-984. Doi:10.1016/S0140-6736(21)00213-0
5. Wadden TA, Bailey TS, Billings LK, et al. Effect of Subcutaneous Semaglutide vs Placebo as an Adjunct to Intensive Behavioral Therapy on Body Weight in Adults With Overweight or Obesity (STEP 3 (Wadden et al., JAMA, 2021)). JAMA. 2021;325(14):1403-1413. Doi:10.1001/jama.2021.1831
6. Garvey WT, Batterham RL, Bhatt DL, et al. Two-Year Effects of Semaglutide in Adults with Overweight or Obesity (STEP 5 (Garvey et al., Nat Med, 2022)). Nat Med. 2022;28:2083-2091. Doi:10.1038/s41591-022-02026-4
7. Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med. 2023;389(24):2221-2232. Doi:10.1056/NEJMoa2307563

Nothing in this article should be construed as medical advice. The information provided is educational only. Always consult with your healthcare provider before beginning, modifying, or discontinuing any medication or treatment. FormBlends connects patients with licensed providers for individualized care.

Last updated: 2026-03-24