How much bacteriostatic water do I add to a peptide vial?

The amount of BAC water depends on the vial size and your desired concentration. A common approach: add 2 ml of BAC water to a 5 mg vial to get a concentration of 2.5 mg/ml, or add 2 ml to a 10 mg vial for 5 mg/ml. Use the calculator above to see exact syringe units for any combination.

How do I calculate peptide dose after reconstitution?

Use the reconstitution formula: Concentration (mg/ml) = Peptide Mass (mg) ÷ Water Volume (ml). Then: Dose Volume (ml) = Desired Dose (mg) ÷ Concentration (mg/ml). Finally, convert to syringe units: Units = Dose Volume (ml) × 100. For example, 10 mg in 2 ml = 5 mg/ml. For a 250 mcg (0.25 mg) dose: 0.25 ÷ 5 = 0.05 ml = 5 IU.

What is the peptide reconstitution formula?

The reconstitution formula is: Concentration = Vial Mass ÷ Water Volume. Then: Injection Volume = Desired Dose ÷ Concentration. Syringe Units = Injection Volume × 100 (for a standard 100-unit insulin syringe). This calculator does all the math for you — just enter your vial size, BAC water amount, and target dose.

What is the difference between IU (insulin units) and ml?

On a standard 100-unit insulin syringe, 100 IU = 1 ml. So 10 IU = 0.10 ml, 5 IU = 0.05 ml, etc. IU and 'units' are the markings on the syringe, while ml is the actual volume. They are directly proportional: divide IU by 100 to get ml. 1 cc = 1 ml exactly.

How long does reconstituted peptide last?

Reconstituted peptides stored in bacteriostatic water typically last 28-30 days when refrigerated at 2-8°C (36-46°F). BAC water contains 0.9% benzyl alcohol which acts as a preservative. Never freeze reconstituted peptides, and always store them away from light. If the solution becomes cloudy or discolored, discard it.

Can I use sterile water instead of bacteriostatic water?

You can, but it's not recommended for multi-dose vials. Sterile water lacks the benzyl alcohol preservative found in BAC water, so reconstituted peptides must be used within 24 hours. BAC water allows the solution to last up to 30 days refrigerated. Only use sterile water if you plan to use the entire vial in a single session.

How do I reconstitute a peptide step by step?

1) Clean the vial stopper with an alcohol swab. 2) Draw your desired amount of BAC water into a syringe. 3) Insert the needle into the vial at an angle, letting the water run down the side of the vial — never spray directly onto the powder. 4) Gently swirl (don't shake) until fully dissolved. 5) Store refrigerated at 2-8°C.

What syringe should I use for peptide injections?

Most peptide users use a 100-unit (1 ml) insulin syringe with a 29-31 gauge needle, ½ inch length. The fine gauge minimizes discomfort for subcutaneous injections. For very small doses (under 5 IU), a 0.3 ml (30-unit) insulin syringe provides better precision with more visible markings.

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Peptide Reconstitution Calculator

Concentration, dose volume, syringe units. Full guide →

View full Peptide Cheat Sheet with dosing protocols →

Quick presets — select a compound to auto-fill:

How it works

10mg vial + 2ml BAC = 5mg/ml. For 250mcg dose → draw 5 IU on a 100-unit insulin syringe.

Peptide in Vial

Total peptide mass on the vial label

BAC Water Added

Amount of bacteriostatic water to add

Desired Dose

Your target dose per administration

Draw to

100

10.0 units

Draw to this line

Pull syringe to

10.0 IU

0.100 ml per dose

100

10.0 units

Draw to this line

Results

Your Answer

Draw to 10.0 IU for a 500 mcg dose.

10.0

Concentration

5.00

mg/ml

5000 mcg/ml

Dose Volume

0.100

Volume to draw per dose

Syringe Draw

10.0

On a 100-unit insulin syringe

Doses per Vial

doses

20.0 exact

Get the full cheat sheet

Quick Syringe Reference

Units

Volume (ml)

Dose (mcg)

Dose (mg)

5 IU

0.05

250

0.250

10 IU

0.10

500

0.500

15 IU

0.15

750

0.750

20 IU

0.20

1000

1.000

25 IU

0.25

1250

1.250

50 IU

0.50

2500

2.500

How to Reconstitute Peptides

Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into a liquid solution for injection. The most common solvent is bacteriostatic water (BAC water), which contains 0.9% benzyl alcohol as a preservative.

The reconstitution formula is straightforward:

Concentration = Vial Mass (mg) ÷ Water Volume (ml)

Syringe Units = [Desired Dose (mcg) ÷ Concentration (mcg/ml)] × 100

For example, adding 2 ml of BAC water to a 10 mg vial produces a concentration of 5 mg/ml (5,000 mcg/ml). To inject 250 mcg, you would draw 5 IU on a standard 100-unit insulin syringe.

Always add water slowly down the inside wall of the vial — never spray directly onto the peptide powder, as this can damage the molecule. Gently swirl to dissolve; do not shake. Store reconstituted peptides refrigerated at 2-8°C and use within 28-30 days.

Looking for dosing protocols?

Complete dosing cheat sheet with cycle lengths, bloodwork markers, vendor links, and reconstitution math for 40+ compounds.

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Common Peptide Reconstitution Presets

Healing & Recovery

Peptide	Vial	Solvent	Dose	Syringe
BPC-157	10 mg	2 ml BAC	500 mcg	10.0 IU
TB-500	10 mg	2 ml BAC	3000 mcg	60.0 IU
BPC/TB Blend	20 mg	2 ml BAC	500 mcg	5.0 IU
GHK-Cu	50 mg	3 ml BAC	2000 mcg	12.0 IU
KPV	10 mg	2 ml BAC	500 mcg	10.0 IU
Thymosin α1	10 mg	2 ml BAC	1500 mcg	30.0 IU
Glow Blend	70 mg	3 ml BAC	1670 mcg	7.2 IU
KLOW Blend	80 mg	3 ml BAC	1670 mcg	6.3 IU

Fat Loss & Metabolic

Peptide	Vial	Solvent	Dose	Syringe
Semaglutide	30 mg	3 ml BAC	500 mcg	5.0 IU
Tirzepatide	60 mg	6 ml BAC	2500 mcg	25.0 IU
Retatrutide	10 mg	3 ml BAC	1000 mcg	30.0 IU
Cagrilintide	10 mg	2 ml BAC	250 mcg	5.0 IU
Tesamorelin	10 mg	2 ml BAC	1000 mcg	20.0 IU
MOTS-c	10 mg	2 ml BAC	1000 mcg	20.0 IU
5-Amino-1MQ	10 mg	2 ml BAC	1000 mcg	20.0 IU
AOD-9604	5 mg	2 ml BAC	300 mcg	12.0 IU

Growth Hormone

Peptide	Vial	Solvent	Dose	Syringe
CJC/Ipa Blend	10 mg	2 ml BAC	250 mcg	5.0 IU
Ipamorelin	5 mg	2 ml BAC	250 mcg	10.0 IU
Sermorelin	5 mg	2 ml BAC	250 mcg	10.0 IU
GHRP-2	5 mg	2 ml BAC	200 mcg	8.0 IU
GHRP-6	5 mg	2 ml BAC	200 mcg	8.0 IU
Hexarelin	2 mg	2 ml BAC	150 mcg	15.0 IU
IGF-1 LR3⚠️	1 mg	1 ml (acetic acid)	100 mcg	10.0 IU
HGH Frag 176-191	5 mg	2 ml BAC	350 mcg	14.0 IU

Cognitive & Mood

Peptide	Vial	Solvent	Dose	Syringe
Semax	30 mg	3 ml BAC	1000 mcg	10.0 IU
Selank	30 mg	3 ml BAC	1000 mcg	10.0 IU
Oxytocin	5 mg	2 ml BAC	50 mcg	2.0 IU
DSIP	5 mg	2 ml BAC	200 mcg	8.0 IU
Kisspeptin-10	5 mg	2 ml BAC	75 mcg	3.0 IU

Immune & Longevity

Peptide	Vial	Solvent	Dose	Syringe
NAD+	500 mg	5 ml BAC	75000 mcg	75.0 IU
Epithalon	10 mg	2 ml BAC	7500 mcg	150.0 IU
LL-37	5 mg	2 ml BAC	175 mcg	7.0 IU

Sexual & Cosmetic

Peptide	Vial	Solvent	Dose	Syringe
PT-141	10 mg	2 ml BAC	500 mcg	10.0 IU
Melanotan 2	10 mg	2 ml BAC	250 mcg	5.0 IU

Frequently Asked Questions

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Drop the reconstitution calculator into any blog post, documentation page, or community site — free, no attribution required beyond the footer link. Pre-fill a specific peptide with URL params like ?peptide=bpc-157 or ?vial=5&water=2&dose=250.

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Compound-Specific Calculators

Pre-filled reconstitution calculators for popular peptides — tap to jump straight to your compound.

BPC-1575mg vial · 250mcg dose TB-5005mg vial · 2500mcg dose Semaglutide5mg vial · 250mcg dose Tirzepatide10mg vial · 2500mcg dose Retatrutide10mg vial · 2000mcg dose CJC-1295 (Mod GRF 1-29)2mg vial · 100mcg dose Ipamorelin5mg vial · 200mcg dose GHK-Cu5mg vial · 200mcg dose PT-141 (Bremelanotide)10mg vial · 1750mcg dose Semax5mg vial · 200mcg dose Selank5mg vial · 250mcg dose MOTS-c5mg vial · 5000mcg dose AOD-96045mg vial · 300mcg dose DSIP2mg vial · 100mcg dose Epithalon10mg vial · 5000mcg dose

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