How do I calculate peptide dosage from a reconstituted vial?

Divide the total peptide amount (in mcg) by the water volume (in ml) to get the concentration. Then divide your desired dose (mcg) by the concentration to get the volume to draw. Multiply by 100 to convert to insulin syringe units. For example: 5 mg peptide in 2 ml water = 2,500 mcg/ml. For a 250 mcg dose: 250 ÷ 2,500 = 0.1 ml = 10 units.

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

Common reconstitution volumes are 1–3 ml. Adding more water creates a more dilute solution, making it easier to measure small doses accurately. For a 5 mg vial, 2 ml is typical. For very small doses (under 100 mcg), consider using 3 ml for better measurement precision with your syringe.

What is the difference between mg, mcg, and IU for peptides?

Milligrams (mg) and micrograms (mcg) are weight-based units: 1 mg = 1,000 mcg. International Units (IU) are activity-based and vary by peptide — there is no universal mg-to-IU conversion. Most peptides are dosed in mcg, while growth hormone is commonly dosed in IU. Always use the unit specified in your dosing instructions.

How many units on an insulin syringe equal 1 ml?

100 units equals 1 ml on all standard insulin syringes (U-100). This means 1 unit = 0.01 ml. A 0.3 ml syringe holds 30 units, a 0.5 ml syringe holds 50 units, and a 1.0 ml syringe holds 100 units.

How long does a reconstituted peptide vial last?

Once reconstituted with bacteriostatic water, most peptides should be used within 3–4 weeks when stored at 2–8°C (refrigerator). Unreconstituted peptide powder can be stored at -20°C for months. Never freeze reconstituted solutions, and avoid repeated freeze-thaw cycles.

What syringe size should I use for peptide injections?

For most peptide doses, a 0.5 ml (50-unit) or 1.0 ml (100-unit) insulin syringe works well. If your dose is very small (under 10 units), use a 0.3 ml syringe for better precision. The finer graduation marks on smaller syringes make it easier to draw accurate small volumes.

Can I use sterile water instead of bacteriostatic water?

Yes, but bacteriostatic water (which contains 0.9% benzyl alcohol as a preservative) is preferred for multi-dose vials because it inhibits bacterial growth. If you use plain sterile water, the reconstituted solution should be used within 24 hours and cannot be stored as long.

What does it mean if my dose exceeds the syringe capacity?

If the calculator shows a syringe capacity warning, your required draw volume is larger than your syringe can hold. You can fix this by: (1) using a larger syringe, (2) adding more BAC water to dilute the solution further, or (3) splitting the dose into two injections.

Peptide Calculator

Quick Preset

Pre-fills vial size and water volume. Adjust as needed.

Peptide Amount (mg)

Total peptide powder in vial

Bacteriostatic Water (ml)

Volume of BAC water to reconstitute with

Desired Dose (mcg)

Amount per injection in micrograms

Syringe Size

100 units max — for larger volumes

Dosing Frequency

Vial Cost

Draw Syringe To

10.0units

(0.100 ml)

0255075100

Syringe fill level (100-unit syringe)

Reconstitution Details

5 mg peptide + 2 ml BAC water

Concentration

2,500mcg/ml

Concentration

2.50mg/ml

Volume per Dose

0.100ml

Syringe Draw

10.0units

Vial Supply

How long this vial lasts at 250 mcg per dose

Doses per Vial

20doses

Days Supply

20.0days

Quick Dose Reference

Common doses with your current reconstitution

Dose (mcg)	Volume (ml)	Units	Doses/Vial
50	0.020	2.0	100
100	0.040	4.0	50
150	0.060	6.0	33
200	0.080	8.0	25
250	0.100	10.0	20
300	0.120	12.0	16
500	0.200	20.0	10
750	0.300	30.0	6

How the Peptide Calculator Works

Core formulas for reconstitution and dosage calculation

This calculator determines exactly how much liquid to draw into your syringe when administering a reconstituted peptide. Enter the total peptide amount in the vial (mg), the volume of bacteriostatic water you added (ml), and your desired dose (mcg).

Concentration

Peptide (mg) × 1000 ÷ Water (ml)

Result in mcg/ml

Volume to Draw

Desired dose (mcg) ÷ Concentration

Result in ml

Syringe Units

Volume (ml) × 100

Result in units

Doses per Vial

Total peptide (mcg) ÷ Dose (mcg)

Result in doses

Example — 5 mg vial + 2 ml BAC water, 250 mcg dose

Concentration

2,500

5×1000 ÷ 2

mcg/ml

Volume

0.100

250 ÷ 2500

Syringe

0.1 × 100

units

Doses

5000 ÷ 250

per vial

Peptide Reconstitution Guide

Step-by-step process for dissolving lyophilized peptide powder

Reconstitution is the process of dissolving lyophilized (freeze-dried) peptide powder with a sterile solvent, typically bacteriostatic water (BAC water containing 0.9% benzyl alcohol).

1. Equilibrate Temperature

Allow both the peptide vial and BAC water to reach room temperature. Cold liquids can cause peptide aggregation.

2. Sterilize Stoppers

Wipe the rubber stopper of both vials with a fresh alcohol swab. Let dry for 10 seconds before inserting a needle.

3. Draw BAC Water

Using a sterile syringe, draw the desired volume of bacteriostatic water. Common volumes: 1–3 ml for most peptides.

4. Add Water to Vial

Inject water slowly down the inside wall of the peptide vial at a 45° angle. Do not spray directly onto the powder to avoid foaming.

5. Dissolve Gently

Gently swirl the vial in a circular motion until fully dissolved. Never shake — shaking can denature (damage) the peptide structure.

6. Store Properly

Refrigerate the reconstituted solution at 2–8°C immediately. Label with date and concentration. Use within 3–4 weeks.

Adding more BAC water creates a more dilute solution, making it easier to measure small doses accurately. For very small doses (under 100 mcg), consider using 3 ml of water for better syringe precision.

Understanding Insulin Syringe Units

All insulin syringes use 100 units = 1 ml, regardless of size

Insulin syringes are calibrated at 100 units per milliliter regardless of syringe size. This means 1 unit always equals 0.01 ml. The only difference between syringe sizes is the maximum capacity and graduation precision.

0.3 ml

30 units max

Best for: Micro-doses

Precision: ½ unit marks

0.5 ml

50 units max

Best for: Most peptides

Precision: 1 unit marks

1.0 ml

100 units max

Best for: Large volumes

Precision: 2 unit marks

Key Conversion

1 unit = 0.01 ml = 10 microliters (μl)

100 units = 1.00 ml = 1 cc

Storage & Stability Guidelines

Temperature requirements for peptide powder and reconstituted solutions

Form	Temperature	Duration	Notes
Lyophilized powder	-20°C (freezer)	6–24 months	Long-term storage, sealed
Lyophilized powder	2–8°C (fridge)	1–3 months	Short-term, keep desiccated
Reconstituted (BAC)	2–8°C (fridge)	3–4 weeks	BAC water preservative
Reconstituted (sterile)	2–8°C (fridge)	24 hours	No preservative — use quickly
Room temperature	20–25°C	Avoid	Rapid degradation — only during prep

Never freeze reconstituted solutions. Freeze-thaw cycles cause peptide aggregation and irreversible loss of activity. Only freeze the dry powder form.

Common Mistakes to Avoid

Frequent errors that affect dosing accuracy and peptide integrity

Confusing mg and mcg

1 mg = 1,000 mcg. Entering the wrong unit can result in a 1,000x dosing error. Always double-check whether your dose is in milligrams or micrograms.

Shaking the vial

Shaking creates bubbles and can denature (unfold) the peptide, reducing its effectiveness. Always gently swirl instead.

Spraying water on powder

Injecting BAC water directly onto the peptide cake can cause clumping. Aim the stream at the vial wall and let it trickle down.

Using the wrong syringe scale

Non-insulin syringes use different unit scales. Only use U-100 insulin syringes (100 units = 1 ml) for peptide dosing.

Unit Conversion Quick Reference

Common unit conversions for peptide dosing

From	To	Conversion
1 mg	mcg	× 1,000 = 1,000 mcg
1 mcg	mg	÷ 1,000 = 0.001 mg
1 ml	syringe units	× 100 = 100 units
1 unit	ml	÷ 100 = 0.01 ml
1 ml	cc	= 1 cc (exactly)
1 IU (HGH)	mg	≈ 0.333 mg (varies by peptide)

IU (International Units) are activity-based, not weight-based. There is no universal mg-to-IU conversion — it varies by peptide. Most research peptides are dosed in mcg, while growth hormone is commonly dosed in IU.

Important Safety Information

This calculator is for informational and educational purposes only. It is not medical advice. Always follow the dosing instructions provided by your healthcare provider or the peptide manufacturer.

Use only bacteriostatic water or sterile water for reconstitution

Always use a new, sterile syringe for each injection

Store reconstituted peptides at 2–8°C

Never share needles, syringes, or vials

Frequently Asked Questions

Common questions and detailed answers

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Last updated Mar 24, 2026

Peptide Calculator

Reconstitution Details

Vial Supply

Quick Dose Reference

How the Peptide Calculator Works

Peptide Reconstitution Guide

Understanding Insulin Syringe Units

Storage & Stability Guidelines

Common Mistakes to Avoid

Unit Conversion Quick Reference

Important Safety Information

Frequently Asked Questions

Embed Peptide Calculator

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