How do I calculate peptide concentration after adding water?

Divide the amount in the vial by the volume of water you added. A 10 mg vial mixed with 2 mL gives 10 ÷ 2 = 5 mg/mL, which is the same as 5,000 mcg/mL.

How many units are in 1 mL on a U-100 syringe?

A U-100 insulin syringe is marked so that 100 units equal 1 mL. Each unit is 0.01 mL, so 0.25 mL reads as 25 units.

How do I convert mg to mcg?

Multiply milligrams by 1,000. 1 mg = 1,000 mcg, so 0.25 mg = 250 mcg. To go back, divide mcg by 1,000.

Can I convert units on the syringe back to an amount?

Yes. Divide the units by 100 to get mL, then multiply by the concentration. 20 units = 0.20 mL; at 5 mg/mL that holds 1 mg. The calculator does this when you type units into the units box.

Does adding more water change how much is in the vial?

No. The total in the vial stays the same. More water lowers the concentration, so the same amount takes up more volume and more units on the syringe.

Why is IU treated differently from mg?

IU measures biological activity, not weight, so there is no universal IU-to-mg rule. The calculator uses the IU count printed on your own vial label instead of guessing.

Does PeptideWhiz suggest doses?

No. PeptideWhiz never suggests or recommends an amount. Every number comes from you, and the tool only does the arithmetic. It is not medical advice.

Do I need an account to use the calculator?

No. The calculator is free and works without an account. An account only lets you save results to your stack and tracker.

Peptide Calculator

Vial and water math for PT-141, with a research record of published human trials. Math only, no suggested amounts.

Free · no account needed

Compound (Optional)

Desired Amount Per Dose

units (U-100)

Vial Strength (Total mg of Your Vial)

Reconstitution Solution Added

Titration Schedule (Optional)

Results

Draw to

—units

Enter amount, vial and Reconstitution Solution

ConcentrationConc.

—mg/mL

Your dose

—mg

Doses / vial

—

More than 100 units (over 1 mL). This won't fit in a single U-100 syringe draw. Double-check your numbers or use more water / a smaller amount.

U-100 Syringe · 1 mL

Notes

PeptideWhizpeptidewhiz.app · research use only

Research use only (RUO). Results are math on the values you enter only, not a recommendation or prescription for human use. Not medical advice. Always verify your own measurements. Full disclaimer

About PT-141

PT-141, also called bremelanotide, is a cyclic peptide that activates melanocortin receptors in the brain, mainly MC4R. It was developed from melanotan II, and unlike PDE5 medicines it acts on the nervous system rather than on blood flow.

Research status

Bremelanotide is FDA-approved as a prescription medicine (Vyleesi) for acquired hypoactive sexual desire disorder in premenopausal women. The RECONNECT trials below are its main published evidence.

How the math works for any vial (concentration, U-100 units, mg and mcg) is explained step by step on the main peptide reconstitution calculator page. Read the full What is PT-141? guide for mechanism, trials and conditions researched.

What published studies used

Research record, not a recommendation or protocol

These are published human trials of PT-141 from the PeptideWhiz study library. The last column quotes each study’s PubMed abstract word for word, so it shows what that study reported giving its participants under medical supervision. It is not advice, and the calculator never fills these numbers in on its own: you can copy one only by tapping its button and confirming.

Study	Year	Journal	As reported in the abstract	PubMed
Prespecified and Integrated Subgroup Analyses from the RECONNECT Phase 3 Studies of Bremelanotide.	2022	Journal of women's health (2002)	“Materials and Methods: Patients self-administered bremelanotide 1.75 mg or placebo subcutaneously using an autoinjector, as needed, before sexual activity for 24 weeks.”	PMID 35230162
Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials.	2019	Obstetrics and gynecology	“Two identical phase 3, randomized, double-blind, placebo-controlled, multicenter clinical trials (RECONNECT) evaluated the safety and efficacy of bremelanotide 1.75 mg administered subcutaneously as needed in premenopausal women with hypoactive sexual desire disorder.”	PMID 31599840
Usefulness of ambulatory blood pressure monitoring to assess the melanocortin receptor agonist bremelanotide.	2017	Journal of hypertension	“We studied the effects of bremelanotide administration on ambulatory BP and heart rate (HR), in a randomized, double-blind, placebo-controlled, and parallel-arm trial of three doses of bremelanotide (0.75, 1.25, and 1.75 mg) in 397 premenopausal women with female sexual dysfunction with normotension or controlled hypertension.”	PMID 27977473
An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist.	2006	The journal of sexual medicine	“Eighteen premenopausal women with a primary diagnosis of female sexual arousal disorder were randomly assigned to receive a single intranasal dose of 20 mg bremelanotide or matching placebo in a double-blind manner during the first in-clinic treatment session, and the alternate medication during the second in-clinic treatment session.”	PMID 16839319

Disclaimer: this table is an educational research record. It does not recommend, suggest or endorse any amount, schedule or use, and it is not medical advice. Decisions about any medicine belong with a licensed clinician.

PT-141 calculator FAQ

What is PT-141?

PT-141 is a melanocortin receptor agonist. PT-141, also called bremelanotide, is a cyclic peptide that activates melanocortin receptors in the brain, mainly MC4R.

Is PT-141 approved?

Bremelanotide is FDA-approved as a prescription medicine (Vyleesi) for acquired hypoactive sexual desire disorder in premenopausal women. The RECONNECT trials below are its main published evidence.

Does this page suggest a PT-141 dose?

No. The calculator dose field starts empty and PeptideWhiz never suggests, recommends or calculates an amount for anyone. The study table is a research record of what published trials reported, not a recommendation or protocol.

Where do the study numbers on this page come from?

Each row quotes the abstract of a published human trial (4 trials, 2006 to 2022) word for word, as indexed in PubMed, with a link to the PubMed record. Nothing is rounded, combined or converted.

How does the calculator work with a PT-141 vial?

Pick PT-141 in step 1 if you want it on your result card, then enter the vial amount printed on your own label and the water volume actually added. The tool divides one by the other for concentration and shows the matching U-100 syringe units for an amount you type. Pens and pre-filled syringes are already in liquid form and are not reconstituted.

Sources

Study rows: PubMed records linked in the table (abstracts checked against PubMed on October 31, 2026). Unit math: see the sources on the main calculator.

Reviewed by the PeptideWhiz team on October 31, 2026. For research and education only.