2.5 mg PT-141 in Units: Syringe Chart

How many syringe units 2.5 mg of PT-141 is, for every common vial size and water volume, with the math shown.

Medical review pendingMelanocortin agonistUpdated 20 Oct 2026

Amount: 2.5 mg
At 5 mg/mL: 50 units; e.g. 10 mg vial + 2 mL
At 10 mg/mL: 25 units; e.g. 20 mg vial + 2 mL
Syringe: U-100; 100 units = 1 mL

2.5 mg in units at common mixes

Units on a U-100 syringe (100 units = 1 mL) for a 2.5 mg amount, by vial size and water added. Concentration = vial mg ÷ mL of water; units = dose ÷ concentration × 100.

2.5 mg of PT-141 in syringe units
Vial	Water	Concentration	Units for 2.5 mg	Volume
10 mg	1 mL	10 mg/mL	25 u	0.25 mL
10 mg	2 mL	5 mg/mL	50 u	0.50 mL
10 mg	3 mL	3.333 mg/mL	75 u	0.75 mL

Calculator and full dosing table

Preset to 2.5 mg in a 10 mg vial. Change any value; the table below the result updates with it.

1Vial size

2Bacteriostatic water added

3Dose per injection

4Syringe (U-100)

Draw to

50units

= 0.5 mL on a 1 mL U-100 insulin syringe

10 mg vial2 mL water2.5 mg dose

Concentration: 5 mg/mL
Doses per vial: 4
Weeks (1 dose/wk): 4

Math only. It does not recommend a dose.

Dosing table for a 10 mg vial

Syringe units (U-100) for each dose, by how much bacteriostatic water you add.

PT-141: U-100 syringe units per dose for a 10 mg vial
Dose	1 mL water	2 mL water	2.5 mL water	3 mL water
0.25 mg	2.5	5	6.25	7.5
0.5 mg	5	10	12.5	15
1 mg	10	20	25	30
1.5 mg	15	30	37.5	45
2 mg	20	40	50	60
2.5 mg	25	50	62.5	75

How the math works

Concentration is the vial's milligrams divided by the water you add. Volume to draw is your dose divided by that concentration. On a U-100 syringe, 1 mL is 100 units, so units = mL × 100.

10 mg ÷ 2 mL = 5 mg/mL
2.5 mg ÷ 5 mg/mL = 0.5 mL
0.5 mL × 100 = 50 units

50 units · 0.5 mL · 2.5 mg from 10 mg + 2 mL

Math only. The amounts in these tables are reference values for the arithmetic, not dose recommendations.

Doses to set a 2.5 mg PT-141 vial against

Set against this vial, the label's only dose is 1.75 mg injected under the skin as needed, at least 45 minutes ahead of anticipated sexual activity.^[3]

In the men's crossover trial of subcutaneous doses, erectile dysfunction patients got 4 mg or 6 mg or placebo, which is research dosing and not the approved use.^[4]

What a 2.5 mg vial gives

A 2.5 mg PT-141 vial mixed with 1, 2 or 3 mL of water is 2.5, 1.25, 0.833 mg/mL, so one U-100 unit carries 25, 12.5, 8.33 mcg.

Calculated from vial mg 2.5; water mL 1, 2, 3; units per mL 100. Formula: mg/mL = vialMg / waterMl; mcg per unit = mg/mL x 1000 / 100

Against the quoted doses, a 2.5 mg vial divides as follows (units at 1 / 2 / 3 mL; † marks under 5 units, hard to measure accurately): 1.75 mg (label dose): 1 doses, 0.75 mg left; 70 / 140 / 210 units; 4 mg (ED trial arm): 0 doses, 2.5 mg left; 160 / 320 / 480 units; 6 mg (ED trial arm): 0 doses, 2.5 mg left; 240 / 480 / 720 units.

Calculated from vial mg 2.5; water mL 1, 2, 3; units per mL 100; rows dose mg 1.75, doses 1, remainder mg 0.75, units 70, 140, 210; dose mg 4, doses 0, remainder mg 2.5, units 160, 320, 480; dose mg 6, doses 0, remainder mg 2.5, units 240, 480, 720. Formula: doses = floor(vialMg / doseMg); units = doseMg x waterMl / vialMg x 100

At the label's cap of 8 doses per month, a 2.5 mg vial holds 1 doses of 1.75 mg, which is 0.12 of one month at the cap.

Calculated from vial mg 2.5; dose mg 1.75; label monthly max doses 8. Formula: doses per vial / 8

Is 2.5 mg a labelled strength?

Labelled supply is one single-dose autoinjector holding 1.75 mg in 0.3 mL.^[3]

A 2.5 mg vial is 1.43 times the labelled 1.75 mg autoinjector strength, and the label sells no multi-dose vial.

Calculated from vial mg 2.5; labelled strength mg 1.75. Formula: ratio = vialMg / 1.75

Common questions

How many units is 2.5 mg of PT-141?

It depends on the concentration. With a 10 mg vial and 2 mL of water (5 mg/mL), 2.5 mg is 50 units on a U-100 syringe. The table shows other mixes.

Is 2.5 mg a recommended dose of PT-141?

This page is math only. It converts an amount into syringe units and does not recommend a dose. See the dosage page for what studies used.

How many syringe units is a 2.5 mg PT-141 vial?

Drawing the full 2.5 mg vial into 1, 2 or 3 mL gives 2.5, 1.25, 0.833 mg/mL; the full vial is 100 units per mL of water used.

Calculated from vial mg 2.5; water mL 1, 2, 3. Formula: mg/mL = vialMg / waterMl

More on PT-141

DosageDoses used in published studies, with the source for each.CalculatorVial, water and dose to syringe units.Side effectsWhat labels and studies report, and what is unknown.BenefitsClaimed benefits next to what published studies measured.How it worksTarget, mechanism and how long it acts, from the label or studies.Nasal sprayStudies that gave PT-141 as nasal spray, and what is approved.

Sources

1Metric (SI) Prefixes (NIST Reference on Constants, Units, and Uncertainty)National Institute of Standards and Technology (NIST) · 2025physics.nist.govAccessed 2 Oct 2026
2BASAGLAR (insulin glargine) injection, prescribing information (DailyMed)U.S. Food and Drug Administration / DailyMed (Eli Lilly and Company label) · 2026dailymed.nlm.nih.govAccessed 2 Oct 2026
3VYLEESI prescribing information (FDA label)FDA label, DailyMed · current labeldailymed.nlm.nih.govAccessed 2 Oct 2026
4Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra.International journal of impotence research · 2004PMID 14999221Accessed 2 Oct 2026

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