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Editorial Reference / Tools

Peptide Reconstitution Calculator

Enter what is in the vial, how much bacteriostatic water you added, and your dose. The tool returns the exact volume to draw, in insulin-syringe units, and handles milligrams as well as IU for growth hormone.

Draw to

10 units

= 0.1 mL on a 100-unit syringe

Concentration
2.5 mg/mL
value
2,500 mcg/mL
Doses per vial
20
050100 units

5 mg in 2 mL = 2.5 mg/mL. For a 250 mcg dose, draw 10 units (0.1 mL) on a 100-unit syringe. 20 doses per vial.

This tool does arithmetic on the numbers you enter. It is educational reference material, not medical advice, a dosing recommendation, or an endorsement of any compound. Many research peptides are prescription-only or investigational and are not approved for human use. Its output is only as accurate as the vial’s actual labelled content, which is why an independently verifiable certificate of analysis matters.

How the calculation works

Reconstitution is one division problem repeated three times. First, concentration: the amount of peptide in the vial divided by the volume of bacteriostatic water you add. A 5 mg vial in 2 mL of water is 2.5 mg/mL, or 2,500 mcg/mL. Adding more water does not change how much peptide you have; it only spreads the same peptide through more liquid, which lowers the concentration and raises the volume you draw for a given dose.

Second, the draw: your dose divided by the concentration gives the volume to pull into the syringe. A 250 mcg dose at 2,500 mcg/mL is 0.1 mL. Third, syringe units: an insulin syringe is marked in units, not millilitres, and on a U-100 syringe 1 mL is 100 units, so 0.1 mL is 10 units. The calculator does all three steps and shows the unit mark to draw to.

Milligrams and IU (growth hormone)

Growth hormone is usually dosed in international units (IU) rather than milligrams. Recombinant human growth hormone (somatropin) is standardised at roughly 3 IU per milligram, so a 10 mg vial holds about 30 IU. The calculator converts between the two using that factor, which you can adjust, so you can enter the vial in milligrams and your dose in IU (or the reverse) and still get the correct draw. HCG is also supplied and dosed in IU and works the same way.

Reading the result

Draw to the unit mark shown. If the volume needed is larger than a single syringe holds, the tool says so; the fix is to reconstitute with more water next time, which lowers the concentration and puts the dose within one syringe. The “doses per vial” figure is the whole number of doses the vial yields at your chosen dose, useful for planning and for sanity-checking that the concentration is sensible.

Two companion references cover the inputs in depth: how the diluent itself affects quality in bacteriostatic water, sterility, and reconstitution, and how a reconstituted peptide holds up over time in peptide stability, storage, and shelf life. The number the calculator returns is only meaningful if the vial actually contains what the label says, which is what a certificate of analysis is for.

Common questions

How much bacteriostatic water should I use to reconstitute a peptide?
There is no single correct amount. The water volume sets the concentration, not how much peptide you have, so common choices are 1, 2, 3, or 5 mL. More water gives a larger, easier-to-measure draw per dose at a lower concentration. Choose a volume that puts your dose at a convenient number of syringe units.
How do I convert a peptide dose into insulin-syringe units?
Divide the peptide in the vial by the water to get the concentration, then divide your dose by that concentration to get the volume in millilitres. On a U-100 syringe, 1 mL is 100 units, so multiply the millilitres by 100. The calculator does all three steps.
How do milligrams and IU relate for growth hormone?
Recombinant human growth hormone (somatropin) is standardised at about 3 IU per milligram, so a 10 mg vial holds about 30 IU. Enter the vial in milligrams and the dose in IU, or the reverse, and adjust the IU-per-mg field if your product states a different factor.
How many doses are in a vial?
Divide the total peptide in the vial by your dose per injection. The calculator shows the whole number of doses available at the dose you enter.

Doses reported in studies

The figures below are amounts reported in FDA labels, clinical trials, or peer-reviewed research. They describe what published studies used, and are reference material only, not a recommendation, a protocol, or an endorsement. Many of these compounds are prescription-only or investigational, and several research peptides have no established human dose at all, which is stated plainly here rather than filled with anecdotal numbers. Enter your own figure in the calculator above.

  • SemaglutideOzempic, Wegovy

    FDA label

    0.25 mg escalating to 2.4 mg SC once weekly (titrated at 4-week steps) (SC)

    FDA-approved (type 2 diabetes; chronic weight management) Source

  • TirzepatideMounjaro, Zepbound

    FDA label

    2.5 mg start, titrated in 2.5 mg steps to a maximum of 15 mg SC once weekly (SC)

    FDA-approved (type 2 diabetes; weight management) Source

  • TesamorelinEgrifta

    FDA label

    1.4 mg SC once daily (1.28 to 2 mg across formulations) (SC)

    FDA-approved (HIV-associated lipodystrophy) Source

  • PT-141 (bremelanotide)Vyleesi

    FDA label

    1.75 mg SC as needed (maximum one dose per 24 h, eight per month) (SC)

    FDA-approved (HSDD in premenopausal women) Source

  • Human Growth Hormone (somatropin)HGH, Genotropin, Norditropin

    FDA label

    Adult GH deficiency about 0.2 mg/day SC (range 0.15 to 0.3), titrated by IGF-1; roughly 0.45 to 0.9 IU/day (SC)

    FDA-approved (multiple brands and indications) Source

  • HCGPregnyl, Novarel

    FDA label

    500 to 4,000 USP units (IU) IM, indication-dependent (dosed in IU, never mg) (IM)

    FDA-approved (hypogonadotropic hypogonadism, others) Source

  • SermorelinGHRH (1-29), Geref

    FDA label

    30 mcg/kg/day SC (pediatric GH deficiency); about 1 mcg/kg IV as a diagnostic (SC / IV)

    Formerly FDA-approved (Geref); withdrawn commercially, now compounded Source

  • Thymosin Alpha-1Thymalfasin, Zadaxin

    Clinical trial

    1.6 mg SC twice weekly (chronic hepatitis B pivotal trials) (SC)

    Approved in 30+ countries, not FDA-approved in the US Source

  • RetatrutideLY3437943

    Clinical trial

    1 to 12 mg SC once weekly in the Phase 2 obesity trial (2 mg start to limit GI effects) (SC)

    Investigational, not approved (Phase 3 TRIUMPH ongoing) Source

  • Ipamorelin

    Clinical trial

    0.03 mg/kg IV twice daily (Phase 2 postoperative-ileus trial; primary endpoint not met) (IV)

    No approved indication; body-composition use is research only Source

  • CJC-1295 (with DAC)Mod GRF (1-29) is the no-DAC form

    Clinical trial

    1 to 30 mcg/kg SC (Phase 1, long-acting DAC form). The no-DAC form has no comparable human data (SC)

    Not FDA-approved; research use only Source

  • Kisspeptin-54

    Clinical trial

    1.6 to 12.8 nmol/kg SC (IVF oocyte-maturation trigger). Doses are molar, not mass (SC)

    Investigational; research use only Source

  • Melanotan-2MT-II (not bremelanotide)

    Clinical trial

    0.025 mg/kg SC in erectile-function studies (SC)

    Not approved anywhere; distinct from FDA-approved bremelanotide Source

  • GHRP-2 (pralmorelin)

    Research literature

    About 1 mcg/kg IV bolus (100 mcg diagnostic dose approved in Japan) (IV)

    Diagnostic approval in Japan only; not FDA-approved Source

  • GHRP-6

    Research literature

    About 1 mcg/kg IV bolus in acute GH-release studies (IV)

    Never approved; research use only Source

  • HexarelinExamorelin

    Research literature

    0.5 to 2 mcg/kg IV in acute GH-release studies (IV)

    Never approved; research use only Source

  • DSIPDelta sleep-inducing peptide

    Research literature

    25 nmol/kg IV in small 1980s insomnia studies (molar dose) (IV)

    Never approved; research use only Source

  • Selank

    Research literature

    About 600 to 2,700 mcg/day intranasal (registered in Russia). No established injectable dose (Intranasal)

    Registered in Russia (intranasal) only; injectable use is research only Source

  • Semax

    Research literature

    0.1% to 1% intranasal solution (registered in Russia). No established injectable dose (Intranasal)

    Registered in Russia (intranasal) only; injectable use is research only Source

  • BPC-157

    No human dose

    No established human dose.

    No established human dose; Rx-only (Schedule 4) in Australia since June 2024; research use only Source

  • TB-500thymosin beta-4 fragment

    No human dose

    No established human dose.

    No established human dose. Human trials used IV full-length thymosin beta-4 (450 to 1,200 mg), not this SC fragment Source

  • GHK-Cucopper tripeptide-1

    No human dose

    No established human dose.

    No established injectable dose (published human data are topical/cosmetic only); research use only Source

  • MOTS-c

    No human dose

    No established human dose.

    No completed human trial of MOTS-c; no established dose; research use only Source

  • EpithalonEpitalon

    No human dose

    No established human dose.

    No established dose for the synthetic tetrapeptide (human data are for the pineal extract Epithalamin); research use only Source

  • NAD+

    No human dose

    No established human dose.

    No FDA-approved injectable product and no controlled trial establishing an injectable dose

Weight-based figures (mcg/kg, mg/kg) and molar figures (nmol/kg) are shown as the studies expressed them; turning them into a fixed dose needs body weight or molecular weight and is outside what this calculator does. Always confirm a compound’s legal status and speak to a qualified clinician. This page is not medical advice.