How the calculation works
Reconstitution math has three steps, and each one is simple on its own. Divide the milligrams of peptide in the vial by the millilitres of bacteriostatic water you add, and you have the concentration in milligrams per millilitre. Divide your prescribed dose by that concentration, and you have the volume in millilitres. Multiply that volume by 100 to express it in U-100 units, since one unit is 0.01 mL by definition.
A worked example makes the pattern obvious. A 5 mg vial mixed with 2 mL of bacteriostatic water gives a concentration of 2.5 mg per mL, which is 25 mcg in every syringe unit. A prescribed dose of 300 mcg is 0.12 mL, or 12 units, and that vial holds 16 full doses at that amount.
Why milligrams, micrograms and units are not interchangeable
Three different scales appear on the same workflow, which is where most confusion starts. Milligrams describe the dry peptide in the vial. Micrograms usually describe the prescribed dose, and there are 1,000 micrograms in a milligram. Units describe volume rather than drug, so the same number of units delivers a different amount of peptide at every concentration. Graduation intervals also differ between syringes, so always read the markings on the barrel in your hand.
Changing the amount of water changes what every unit represents, even though the amount of peptide in the vial is unchanged. More diluent means a larger volume for the same dose. Your prescriber and pharmacy label set the diluent volume, not preference.
What bacteriostatic water does
Bacteriostatic water is sterile water containing a small amount of benzyl alcohol, which suppresses bacterial growth so a vial can be entered more than once. Sterile water and saline are not the same thing and are not interchangeable here. Use whatever diluent your pharmacy specifies, in the volume it specifies.
Where your numbers should come from
Everhuman does not set doses, and neither does this page. All three inputs belong to your prescription: the vial strength printed on the label, the diluent volume your pharmacy instructs, and the dose your prescriber determined after reviewing your history and labs. The calculator converts those numbers between scales, and nothing more.
Anyone quoting a standard peptide dose from a forum or a vendor page is guessing about a person they have never assessed. Compounded medications are not FDA-approved, and a licensed clinician is the only appropriate source for what you should take. If the calculator disagrees with your label, trust the label and call your pharmacy.
How to use this peptide dosage calculator
Three numbers come off your prescription and pharmacy label, and the fourth is the syringe in your hand. Enter the milligrams of peptide in the vial, the millilitres of bacteriostatic water your pharmacy told you to add, and the dose your prescriber wrote for you, then pick your syringe size. The result updates as you type, and the web address updates with it, so you can bookmark a calculation or send it to someone.
A worked example you can check against an FDA label
EGRIFTA SV, a tesamorelin product, is useful here because its FDA label prints both the mixing instructions and the resulting injection volume, which almost no peptide source does. The label directs reconstituting a 2 mg vial with 0.5 mL of sterile water, giving 4 mg per mL, and gives the dose as 1.4 mg, which the label itself prints as 0.35 mL. Entering those figures in the calculator returns 0.35 mL and 35 units, matching the label exactly. Press Load a worked example above to fill them in.
Worth being clear about what that example is and is not. Tesamorelin is a prescription medicine approved for one specific condition, Everhuman does not offer it, and nothing here suggests that anyone should take it or any particular amount of it. The label is cited because a published official source is the right thing to test a calculator against, and because most peptide sources publish no checkable numbers at all.
Frequently Asked Questions
How do you convert peptide mg to units on a syringe?
Converting milligrams to syringe units takes two steps. First divide the milligrams in the vial by the millilitres of bacteriostatic water added to get the concentration in mg per mL, then divide your prescribed dose by that concentration to get the volume in millilitres. Multiply that volume by 100 to read it in units, because one unit on a U-100 insulin syringe equals 0.01 mL.
How many units is 250 mcg of a peptide?
No single answer applies, because units measure volume rather than drug, so the number depends entirely on the concentration in your vial. A 250 mcg dose from a vial at 2.5 mg per mL is 10 units, while the same dose from a vial at 5 mg per mL is 5 units. Enter your own vial strength and diluent volume above to get the figure that matches what is in front of you.
How much bacteriostatic water should I add to a peptide vial?
The diluent volume is specified by your prescribing clinician and your pharmacy label, and this calculator does not recommend one. Adding more water makes each dose a larger and easier to measure volume, while adding less makes it smaller and more concentrated, but the total amount of peptide in the vial is unchanged either way. Follow the volume your pharmacy gives you.
Does reconstituting a peptide change the total volume?
Dry peptide at these masses adds a negligible amount of volume when dissolved, so the final volume is treated as the volume of diluent added. That assumption is what this calculator and standard pharmacy practice both use. For very large masses the difference would matter, but not at typical peptide vial sizes.
Is a 30 unit syringe the same as 0.3 mL?
A 30 unit syringe holds 0.3 mL, because one unit on a U-100 insulin syringe is 0.01 mL. Syringes are commonly labelled by unit capacity rather than volume, which is why 30 unit, 50 unit and 100 unit syringes hold 0.3 mL, 0.5 mL and 1.0 mL. Check that your syringe is marked U-100 before relying on that conversion.
Can this calculator tell me what dose to take?
No, and by design. The calculator performs arithmetic on numbers you enter and never suggests, recommends or defaults to a dose. Only a licensed clinician who has reviewed your history, medications and labs can determine whether a peptide is appropriate for you and at what amount, and a prescription is not guaranteed.
What is a peptide calculator used for?
A peptide calculator converts between the three scales involved in an injectable peptide: milligrams of dry powder in the vial, millilitres of liquid after mixing, and units marked on the syringe. Those scales do not line up on their own, and the conversion changes every time the vial strength or the amount of diluent changes. Doing that arithmetic by hand is where decimal errors happen.
Does this calculator work for any peptide?
The arithmetic is identical for any peptide supplied as a lyophilised powder that you reconstitute with a liquid, because the calculation depends only on mass, volume and syringe markings rather than on which molecule is in the vial. What differs between peptides is everything clinical: whether one is appropriate for you, and at what amount. Those questions belong to your prescriber, not to a calculator.
What if my syringe is not a U-100 insulin syringe?
Unit markings only mean 0.01 mL on a U-100 syringe, so the unit figure here does not apply to any other syringe. Check the barrel for the U-100 marking before using the unit result. If your syringe is marked only in millilitres, use the millilitre figure instead and ignore units entirely.
Can I save or share a calculation?
Every entry you make is written into the page address, so bookmarking the page keeps your numbers, and sending the link to someone shows them the same result. Use the copy link button under the result to grab it. Treat that link as personal health information and share it only with people you intend to.
Is there an example I can check this calculator against?
Yes, and checking a tool against a published source is a reasonable thing to ask. The EGRIFTA SV label directs mixing a 2 mg vial with 0.5 mL of sterile water and prints the resulting 1.4 mg dose as 0.35 mL. Entering those figures here returns 0.35 mL and 35 units on a U-100 syringe, which is the same answer the label gives.
The honest summary
Reconstitution arithmetic is not difficult, but it is easy to get wrong in your head at eleven at night, and the consequence of a decimal error is real. Doing the conversion on paper or with a tool, then checking it against your pharmacy label, is the sensible habit.
What this page cannot do is tell you what belongs in the dose field. That number comes from a clinician who has assessed you, and no calculator, forum thread or vendor page is a substitute for it.
Compounded medications are not FDA-approved and are not the same as, nor a substitute for, FDA-approved products. This tool does not provide medical advice or recommend a dose. Prescription products require an evaluation by a licensed provider who determines whether a prescription is appropriate. A prescription is not guaranteed. Everhuman does not provide medical advice; clinical care is delivered by Arora Health.