T-01
Reconstitution calculator
Concentration, draw volume, U-100 syringe units, and doses per vial from vial size, water volume, and dose.
Tesamorelin is one of the few peptides where reconstitution is not folklore: the FDA label spells out the vial strength, the diluent volume, and the resulting concentration for each formulation. This calculator preloads those label constants (Egrifta SV: 2 mg vial plus 0.5 mL water gives 2 mg per 0.5 mL; Egrifta WR: 11.6 mg plus 1.3 mL gives 8 mg/mL) and converts any prescribed dose into injection volume and U-100 syringe units.
Results
- Concentration
- 4 mg/mL4000 mcg/mL
- Volume per dose
- 0.35 mL
- U-100 syringe units per dose
- 35 unitsFits the 1 mL barrel (100 unit scale).
- Full doses per vial
- 1 doses
Arithmetic only: concentration = vial mg / water mL; units = mL x 100. It does not check any dose against any reference.
Worked example
Example, straight from the Egrifta SV label: a 2 mg vial reconstituted with 0.5 mL of Sterile Water for Injection gives 2 / 0.5 = 4 mg/mL (math note). The labeled 1.4 mg dose is 1.4 / 4 = 0.35 mL, which reads as 35 units on a U-100 syringe (math note). The label then says to inject immediately and discard the rest of the vial, so one vial is one dose, whatever the leftover volume suggests.
Step by step
- Confirm which formulation is in your hand: SV (2 mg vial) and WR (11.6 mg vial) have different diluents, concentrations, and rules, and their labels say they are not substitutable.
- Add the label-specified diluent volume: 0.5 mL sterile water for SV; 1.3 mL bacteriostatic water for WR.
- Mix gently per label: roll the SV vial in your hands for 30 seconds, swirl the WR vial; never shake either.
- Inspect: use only a clear, colorless solution without particles.
- Compute the draw: dose divided by concentration gives millilitres; millilitres times 100 gives U-100 units.
- Follow the discard rule: SV remainder is discarded immediately after the injection; the WR vial is discarded 7 days after mixing.
The label's own reconstitution constants (these are the only sourced presentations)
| Presentation | Vial | Diluent | Concentration | Labeled dose | Doses per vial | Source |
|---|---|---|---|---|---|---|
| Egrifta SV | 2 mg | 0.5 mL Sterile Water for Injection | 4 mg/mL (2 mg per 0.5 mL) | 1.4 mg = 0.35 mL = 35 U-100 units | 1 (inject immediately, discard remainder) | source |
| Egrifta WR | 11.6 mg | 1.3 mL Bacteriostatic Water for Injection | 8 mg/mL | 1.28 mg = 0.16 mL = 16 U-100 units | 7 (label cap; discard 7 days after mixing) | source |
| Egrifta (2010, historical) | 1 mg | per 2010 label | 1 mg/mL | 2 mg daily (two vials) | single-use vials, refrigerated before mixing | source |
Frequently asked questions
How do mg, mL, and syringe units relate here?
Units measure volume: a U-100 syringe marks 100 units per mL, so units = mL x 100 (math note). At the SV label concentration of 4 mg/mL, the 1.4 mg dose is 0.35 mL, which is 35 units. At WR's 8 mg/mL, 1.28 mg is 0.16 mL, 16 units. Same drug, different concentration, different draw.
A U-100 insulin syringe divides each millilitre into 100 units, so units are volume, not peptide: units = mL x 100 (math note). How much tesamorelin each unit carries depends entirely on concentration. Egrifta SV reconstitutes to 4 mg/mL (2 mg in 0.5 mL), so the labeled 1.4 mg dose is 0.35 mL, read as 35 units. Egrifta WR reconstitutes to 8 mg/mL, so its 1.28 mg dose is 0.16 mL, read as 16 units.
That difference is exactly why the labels state the two formulations are not substitutable: transplanting a unit count from one to the other delivers the wrong dose. Always compute from the box in your hand.
The SV vial holds 2 mg but the dose is 1.4 mg. Can I save the rest?
No. The SV label is explicit: inject immediately after reconstitution and throw away any unused solution, and never refrigerate or freeze the mixed solution. The overfill exists so a full 0.35 mL draw is possible, not as a second partial dose. WR is the formulation designed for multi-day use.
No, and this is a label rule rather than a suggestion. Egrifta SV is a single-dose vial: the label says to administer the 0.35 mL dose immediately following reconstitution, discard any unused solution and diluent, and never freeze or refrigerate the reconstituted solution. The extra volume is what makes an accurate full draw possible; it is not a stored second dose, and the preservative-free formulation is part of why.
If multi-day use from one vial is the goal, that is literally what Egrifta WR was built for: its bacteriostatic diluent and label support 7 daily doses from one 11.6 mg vial, with a hard discard at day 7. Which formulation you receive is a prescriber and pharmacy decision.
Where does the injection go, and why only the abdomen?
The label names one region: subcutaneous injection into the abdomen, rotating sites, avoiding scar tissue, bruises, and the navel. Rotation is the label's answer to injection site reactions (25% vs 14% on placebo). General technique guidance adds short needles and never reusing one spot.
The label is unusually specific: inject subcutaneously into the abdomen, rotate injection sites to different areas of the abdomen, and do not inject into scar tissue, bruises, or the navel. Rotation is not ritual: injection site reactions (erythema, pruritus, pain, bruising) occurred in 25% of tesamorelin patients versus 14% on placebo in the trials, and rotating is the label's stated mitigation.
Broader subcutaneous technique guidance points the same way: the shortest needles are first-line, and systematic rotation keeps lipohypertrophy, tissue thickening that can distort absorption, from developing. If a site develops persistent lumps, redness, or pain, that is a conversation with the prescriber or pharmacist, not something to inject through.
What if I mixed with a different volume than the label says?
Recompute before injecting: concentration follows what actually went in (math note). An SV vial mixed with 0.25 mL instead of 0.5 mL holds 8 mg/mL, so an unchanged 35-unit draw would deliver 2.8 mg, double the dose. If unsure what went in, the safe answer is the pharmacist, not an estimate.
Recompute before anything is injected. Concentration equals vial contents divided by the volume that actually went in, not the volume that was planned (math note). Mix a 2 mg SV vial with 0.25 mL instead of 0.5 mL and the solution is 8 mg/mL rather than 4; the same 0.35 mL, 35-unit draw now carries 2.8 mg instead of 1.4 mg, twice the labeled dose. The opposite error, too much diluent, underdoses the same way.
Enter the real vial and the real volume into the calculator and read the corrected draw for the prescribed dose. Also note the diluents are not interchangeable between formulations (SV uses sterile water; WR uses bacteriostatic water), and if you cannot reconstruct what went into the vial, discard it and call the pharmacy rather than guessing.
Tools: educational calculators and references only.