PT-141 Reconstitution Calculator
Enter how much bacteriostatic water you added to your 10mg PT-141 vial and the amount you want per draw. The calculator reports the concentration, where the draw lands on an insulin syringe, and how many draws the vial holds.
What is the total volume of your syringe?
Printed on the barrel. Insulin syringes are marked in units, at 100 units to the millilitre.
To draw 250 mcg, pull the plunger to 7.5 units on your 1.0 mL syringe.
- Concentration
- 3.33 mg/mL
- Per unit
- 33.3 mcg
- Draw volume
- 0.075 mL
- Draws per vial
- 40
For research purposes only. Not for human consumption. All products are sold strictly as in-vitro laboratory reagents to qualified researchers, and are not drugs, foods, cosmetics or medical devices. They are not intended to diagnose, treat, cure or prevent any disease, and must not be administered to humans or animals. You must be 21 or older to purchase.
Reconstituting a vial
Lyophilised powder has to be dissolved before any of the arithmetic above applies. These are general laboratory handling notes for research material.
Work on a wiped-down surface with nothing on it but what the procedure needs. Sterility is the whole game here: a solution that picks up contamination on the bench stays contaminated for the entire life of the vial, and nothing later in the process removes it.
Have the lyophilised vial, bacteriostatic water, a sterile syringe, alcohol swabs and gloves laid out before you start, so that no step is done one-handed while reaching for something.
Take the powder and the solvent out of cold storage and let them come up to room temperature before combining them. Cold solvent dissolves lyophilised material slowly and unevenly, which is what produces the stubborn clumps that get mistaken for a bad vial.
Swab the rubber stopper on both vials with alcohol and let it dry rather than wiping it off.
Draw the volume you entered above, then hold the vial at an angle and let the water run down the inside wall rather than jetting it directly onto the powder. Peptides are fragile in solution, and a hard stream foams them.
Let it dissolve on its own. Swirl gently if it needs help. Do not shake — foam on the surface is denatured material, and it is not coming back.
Unreconstituted powder is the stable form and should stay cold and dark until you need it. Once it is in solution the clock starts: refrigerated, most peptides hold for a few weeks; frozen, for a few months.
Freeze in single-use aliquots rather than repeatedly thawing one vial. Each freeze-thaw cycle costs potency, and the loss does not announce itself — the solution looks identical either way.
Looking for a particular compound? Browse the catalogue, or ask us what documentation exists for the lot in stock.
About PT-141
PT-141 (bremelanotide) is a synthetic cyclic heptapeptide and melanocortin receptor agonist, derived from the alpha-MSH analogue Melanotan II. It is studied in neuroendocrine and melanocortin-pathway research.
Reconstituting a 10mg vial
PT-141's 10mg vial follows the standard arithmetic -- 2mL gives 5mg/mL, 3mL gives 3.33mg/mL -- but it belongs to the melanocortin family and shares that family's light sensitivity. Reconstituted solution should be kept refrigerated and out of direct light. As with the other melanocortin analogues here, the powder can look like almost nothing at the bottom of the vial; a vial that appears empty usually is not.
10mg PT-141 concentration chart
What a 10mg vial becomes at four common reconstitution volumes, on a U-100 insulin syringe.
| Bacteriostatic water | Concentration | Per unit on the barrel | Total units in the vial |
|---|---|---|---|
| 1mL | 10mg/mL | 100mcg | 100 units |
| 2mL | 5mg/mL | 50mcg | 200 units |
| 3mL | 3.33mg/mL | 33.33mcg | 300 units |
| 5mL | 2mg/mL | 20mcg | 500 units |
A U-100 insulin syringe is marked at 100 units to the millilitre. Concentration is the vial strength divided by the volume of water added; nothing on this chart is a recommendation about how much of that solution to use.
PT-141 from Ascend Vials
Sourced against a 99%+ identity purity specification, shipped anywhere in the continental United States for a flat $4.99 and arriving in 2–4 days. For in-vitro laboratory research only.
PT-141 reconstitution questions
- How much bacteriostatic water should be added to a 10mg PT-141 vial?
- There is no single correct volume — the amount of water decides the concentration, and the concentration decides how legible the result is on the barrel of your syringe. For a 10mg vial: 2mL gives 5mg/mL, and 3mL gives 3.33mg/mL. More water means a lower concentration and a longer, easier-to-read draw; less water means the vial lasts across more draws. Bacteriostatic water contains a preservative, so a vial reconstituted with it can be drawn from repeatedly.
- What concentration is 10mg of PT-141 in 3mL of bacteriostatic water?
- 10mg dissolved in 3mL gives a concentration of 3.33mg per mL. A U-100 insulin syringe holds 100 units per mL, so each unit on the barrel contains 33.33mcg, and the reconstituted vial holds 300 units of solution in total.
- How many units on an insulin syringe is 1mL of reconstituted PT-141?
- On a standard U-100 insulin syringe, 1mL is 100 units — that is what U-100 means, and it is true regardless of what is dissolved in the liquid. A 0.5mL syringe is marked to 50 units and a 0.3mL syringe to 30 units, at the same 100-units-per-mL scale. What changes with the compound is how much material each unit carries, which is the concentration figure above.