Tesamorelin Dosage Calculator: Reconstitution and Unit Conversion

Tesamorelin is dosed in whole milligrams. Almost every peptide sold beside it is dosed in hundreds of micrograms. That single difference causes most of the dosing errors made with this compound, because the arithmetic looks identical right up to the point where the answer is wrong by a factor of ten.

This page is the calculation, written out. Vial strength in, bacteriostatic water volume in, an exact insulin syringe mark out, with a chart for the common combinations and a section on the errors that turn a 2mg dose into a 0.2mg one without anything on the bench looking unusual.

The Three Numbers a Tesamorelin Calculation Needs

Every reconstitution question reduces to three figures, and with all three the answer is arithmetic rather than judgement.

• Vial strength. The milligrams of lyophilised peptide in the vial. Research vials are commonly 5mg or 10mg. The pharmaceutical presentation is 2mg.
• Diluent volume. The millilitres of bacteriostatic water you add. This is a choice, not a property of the vial, and it is the number people most often assume is fixed.
• Target dose. The milligrams you intend to inject. The trial figure is 2mg.

Two of those are printed on things in front of you. The third, diluent volume, is the one you decide, and it is why two people holding identical vials can correctly draw to completely different marks.

The Formula, Written Out Once

Concentration first. Divide vial strength by diluent volume:

Concentration (mg/ml) = vial strength (mg) ÷ water added (ml)

Then the draw volume. Divide target dose by that concentration:

Draw volume (ml) = target dose (mg) ÷ concentration (mg/ml)

Then the syringe mark. A U-100 insulin syringe puts 100 units across 1ml, so one unit is 0.01ml:

Units = draw volume (ml) × 100

A 10mg vial with 2ml of water is 5mg/ml. A 2mg dose divided by 5mg/ml is 0.4ml, which is 40 units. Nothing in that sequence is difficult, and the serious errors do not happen inside it. They happen at the edges, where a milligram gets read as a microgram or a diluent volume gets assumed instead of measured.

Worked Examples for Every Common Vial Size

All figures below assume a U-100 insulin syringe and a 2mg target dose. That dose is not a community convention: it is the figure used across the phase 3 programme, 2mg once daily by subcutaneous injection for 26 weeks with a 26 week extension, which produced roughly a 15 percent reduction in CT-measured visceral fat. Protocols circulating at 1mg are not a conservative version of the trial, they are a dose with no trial behind them. The compound profile covers the label and its limits.

Read down the units column and the point of the page appears. The same 2mg dose is 20 units in one row and 100 units in another. Anyone who memorises a unit number without the diluent volume attached has memorised nothing useful, and the number they carry to the next vial will be wrong in a way the syringe cannot show them.

Choosing How Much Water to Add

Diluent volume does not change how much peptide you have. It changes how finely you can divide it, and that is a real tradeoff in both directions.

Too little water

A 10mg vial with 0.5ml sits at 20mg/ml, making a 2mg dose a 10 unit draw. At that concentration a single unit of measurement error is 10 percent of the dose, and the meniscus in an insulin syringe is not readable to better than about half a unit in practice. Very concentrated solutions also leave a more meaningful fraction of the dose in the needle hub.

Too much water

A 10mg vial with 5ml is a 100 unit draw that fills the barrel completely and leaves no room to correct an overdraw. It also means many vials will not physically hold the volume. A standard 10ml peptide vial has the headspace, but a 3ml vial does not, and discovering that with the water half in is an unpleasant way to lose a vial.

The readable middle

Aim for a draw between 20 and 60 units. For a 10mg vial at a 2mg dose, 2ml lands you at 40 units, which is comfortably readable, leaves headroom both ways, and divides cleanly for a half dose. The reconstitution guide covers getting the water in without foaming the peptide, which matters more here than with most compounds because the lyophilised cake is easy to disturb.

Why Tesamorelin Specifically Trips People Up

Most growth hormone axis peptides are dosed in the low hundreds of micrograms. Ipamorelin sits around 200 to 300mcg, sermorelin in clinic use runs 200 to 500mcg, and CJC-1295 without DAC is in the same territory. Tesamorelin is 2mg, which is 2000mcg, roughly seven to ten times the milligram quantity of everything sitting next to it in the fridge.

That gap creates two failure modes. The first is habit transfer: someone who has drawn 250mcg of ipamorelin four hundred times has a physical memory of the correct draw, and that memory is actively wrong for tesamorelin, in the direction of underdosing by a factor no amount of careful technique will catch.

The second is unit slippage in written protocols. "2mg" and "2000mcg" describe the same dose. "200mcg" is a tenth of it. Those strings look similar at a glance and are frequently retyped by people who are not checking. Converting any figure to milligrams first removes the ambiguity, because the milligram figure for this compound should always be a small number with a decimal, never a number in the hundreds. It is also why the tesamorelin and sermorelin comparison warns against reasoning on a cost per milligram basis.

Reading the Syringe Mark Without Guessing

U-100 is the standard and the one every unit figure here assumes. It carries 100 units per millilitre, and the barrel sizes that matter are the 0.3ml (30 unit), 0.5ml (50 unit) and 1ml (100 unit) variants.

The smaller barrels are not lower capacity versions of the same thing. They spread the same units across more physical distance, so a 30 unit syringe gives a visibly wider gap between marks than a 100 unit syringe at the same reading. For a 40 unit draw, a 0.5ml barrel is the better instrument: the draw sits in the upper middle of the scale, where on a 1ml barrel it sits in the tighter lower third. If a barrel is marked only in millilitres, divide by 100. The injection guide covers needle selection and site rotation, which are separate decisions from the volume.

Storage, and What the Clock Actually Starts

Lyophilised tesamorelin is stable for a long time. Reconstituted tesamorelin is not, and reconstitution is what starts the clock.

Bacteriostatic water contains benzyl alcohol as a preservative, and the conventional working window for a multi-dose vial reconstituted with it is around 28 days refrigerated at 2 to 8 degrees Celsius. Sterile water has no preservative and should be treated as single day material once the vial is pierced. Get that distinction right before the water goes in, because it is not recoverable afterwards.

Diluent volume and vial life interact. A 10mg vial at 2ml gives five 2mg doses, five days at daily dosing and comfortably inside the window. The problem case is reconstituting a large vial for an intermittent protocol and reaching dose seven in week six. Storage and stability goes through the degradation curves.

The Errors That Produce a Tenfold Mistake

Four errors account for nearly all the serious ones, and they share a property: the syringe looks normal afterwards.

• Assuming the diluent volume. Reusing a unit figure from a previous vial reconstituted differently. The most common one by a distance, and it produces errors of two to five times in either direction.
• Milligram and microgram confusion. Reading 2mg as 200mcg, or writing 2000mcg as 200mcg. Tenfold, and the result still looks plausible for a peptide.
• Counting units as millilitres. Drawing to 0.4 on a barrel marked in units instead of 40. A hundredfold error, and the reason mixed-marking syringes are worth avoiding entirely.
• Trusting an unverified vial strength. The arithmetic is only as good as the label. A vial sold as 10mg containing 6mg makes every calculation here produce a confidently wrong answer, which is why the vendor scorecard weights third party testing as heavily as it does.

The habit that catches three of the four is writing the concentration on the vial in marker the moment the water goes in. Not the units, the concentration in mg/ml. Units are specific to one dose. Concentration is a property of the vial and stays true regardless of what you decide to draw later.

Sourcing Notes

A dosage calculator is worth exactly as much as the vial it is pointed at. If a 10mg vial holds 7mg, every figure in the table above is off by 30 percent and nothing at the bench will reveal it. Batch level certificates of analysis are the only practical check outside a lab, which is why they carry more weight on our scorecard than price does. The before and after page works through the published results, all of which assumed verified material.

Pantheon and Amino Club are the two vendors we track that carry tesamorelin consistently and publish a per-batch COA. Amino Club lists it under the vendor's own spelling, "tesamorlin", which is their catalogue and not a typo on our side. Tesamorelin at Amino Club Compare at Pantheon

Bacteriostatic water is the other half of the calculation and the half people forget to order. It is inexpensive and it is not interchangeable with sterile water for a multi-dose vial. Bacteriostatic water

Tesamorelin is a research compound outside a prescription channel. The trial figures above describe supervised use of a licensed drug in a defined patient population, and nothing on this page is a recommendation to obtain or administer anything.

Frequently Asked Questions

How many units of tesamorelin is 2mg?

There is no fixed answer, because units measure volume and not milligrams. A 10mg vial reconstituted with 2ml of bacteriostatic water sits at 5mg per ml, so 2mg is 0.4ml, which is 40 units. The same vial reconstituted with 1ml sits at 10mg per ml, and the same 2mg dose is then 20 units. The unit number is only meaningful alongside the vial strength and the diluent volume.

How much bacteriostatic water should I add to a tesamorelin vial?

Enough that the dose lands in the readable middle of the syringe. For a 10mg vial at a 2mg target, 2ml gives a 40 unit draw, which is comfortable to read and hard to misjudge. At 0.5ml the draw is 10 units, where a single unit of error is 5 percent of the dose. Volume added does not change the milligrams in the vial, only how finely you can divide them.

What is the standard tesamorelin dose?

2mg once daily by subcutaneous injection, the figure used across the phase 3 programme for 26 weeks with a 26 week extension. That is the only dose with controlled trial support behind it, studied in a specific patient population under medical supervision. Protocols at 1mg circulate but have no trial backing, and the visceral fat results people quote were produced at 2mg.

How do I convert tesamorelin mg to mcg?

One milligram is 1000 micrograms, so 2mg is 2000mcg and a 10mg vial holds 10,000mcg. The conversion matters because tesamorelin is one of the few peptides dosed in whole milligrams while most of its neighbours are dosed in hundreds of micrograms, and the arithmetic gives no warning when a habit from a 300mcg protocol carries across.

How long does reconstituted tesamorelin last?

Refrigerated at 2 to 8 degrees Celsius and reconstituted with bacteriostatic rather than sterile water, a vial is generally treated as usable for around 28 days. That is the standard interval for the benzyl alcohol preservative rather than a figure specific to tesamorelin. Sterile water carries no preservative and should be treated as single day material. Potency loss is gradual, so a vial past its window does not announce itself.