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How to reconstitute tesamorelin
Tesamorelin is the compound where the obvious reconstitution is the wrong one. The standard vial is 2 mg, the standard dose is 1 to 2 mg, and the instinct is to add 2 mL of water because the numbers match. Do that and a full 2 mg dose becomes 200 units, twice what a U-100 syringe holds. This page has the charts for 2, 5 and 10 mg vials and the water volumes that actually work.
Concentration = vial mg ÷ water mL. Units = (dose mg ÷ concentration) × 100. Tesamorelin is the clearest case of the ceiling that catches people: 100 units is 1 mL and that is the whole syringe. Or skip the arithmetic with the reconstitution calculator.
What you need
- • A lyophilized tesamorelin vial. The approved presentation is 2 mg; compounded vials also appear as 5 mg and 10 mg
- • Bacteriostatic water for multi-dose vials. Note that the approved product's own labelling specifies sterile water for a single-dose presentation, which is a different situation from a multi-day compounded vial
- • A U-100 insulin syringe
- • Alcohol swabs, clean hands, a clean surface
The steps
Prep. Wash your hands. Swab the rubber stopper of both the compound vial and the bacteriostatic water with alcohol and let them air dry.
Draw your water. Pull the volume you decided on above into a syringe. This number is the single decision that sets everything downstream.
Add it slowly. Insert the needle and let the water run down the inside glass wall, not jetting straight onto the powder. Foam means sheared peptide.
Dissolve gently. Swirl the vial or roll it between your palms. Never shake. Wait until it is completely clear. Cloudiness or floating particles means do not use it.
Draw the dose. Work out your units from the chart above, swab the stopper again, and draw on a U-100 syringe, tapping air bubbles back out.
Label and refrigerate. Write the concentration and the date on the vial. In four weeks you will not remember either.
Dose-to-units chart
Tesamorelin is dosed at 1 mg or 2 mg daily, injected subcutaneously before bed on an empty stomach. Here is what that costs in units:
| Vial + water | Concentration | 1 mg dose | 2 mg dose |
|---|---|---|---|
| 2 mg + 1 mL | 2 mg/mL | 50 u | 100 u |
| 2 mg + 2 mL | 1 mg/mL | 100 u | 200 u |
| 5 mg + 1 mL | 5 mg/mL | 20 u | 40 u |
| 5 mg + 2 mL | 2.5 mg/mL | 40 u | 80 u |
| 10 mg + 2 mL | 5 mg/mL | 20 u | 40 u |
| 10 mg + 3 mL | ~3.3 mg/mL | 30 u | 60 u |
Red = over a full U-100 syringe. The 2 mg + 2 mL row is the trap, because 1:1 looks like the natural choice.
The 1:1 trap
Adding 2 mL of water to a 2 mg vial feels right. The numbers match, it reads as tidy, and plenty of forum posts recommend it. It produces 1 mg/mL, which means a 1 mg dose is exactly 100 units, the entire barrel of a U-100 syringe, and a 2 mg dose is 200 units, which is two full injections.
Use 1 mL instead. At 2 mg/mL a 1 mg dose is 50 units, sitting at the middle of the barrel where it is easy to read, and a full 2 mg dose is exactly 100 units in a single draw. If you have a larger compounded vial, 5 mg in 1 mL or 10 mg in 2 mL both give 5 mg/mL, which drops a 2 mg dose to a very comfortable 40 units.
This is not a subtle preference. A dose that needs the full barrel leaves no margin for the air bubble you did not tap out, and a dose that needs two syringes doubles both the injection burden and the number of chances to get it wrong.
Daily dosing changes which vial to mix
Tesamorelin is taken every night, which makes vial arithmetic simple and unforgiving. A 2 mg vial at 1 mg daily is two days. At 2 mg daily it is one day. That is not a practical multi-dose vial in any real sense, and it is why compounded 5 mg and 10 mg presentations exist: a 10 mg vial at 2 mg daily is five days, and at 1 mg daily ten days.
Everything still has to land inside the beyond-use date, but with tesamorelin the binding constraint is almost never expiry, it is how often you want to be reconstituting. Mixing every second night is a chore. The vial longevity calculator will tell you how many days any vial and dose combination gives you.
One other consequence of the half-life: tesamorelin clears in about thirty minutes, which is why the dosing is nightly and on an empty stomach rather than weekly. There is no reservoir effect to smooth over a missed dose, so consistency matters more here than with a weekly GLP-1.
Storage & beyond-use dating
The usual 28 days refrigerated figure applies to a compounded multi-dose vial, though in practice tesamorelin vials are consumed long before that at daily dosing. Keep it at 2-8 °C, out of light, never frozen. Label the concentration and date. Because you are drawing from it every night, the vial spends more total time out of the fridge than a weekly compound would, so be brisk about it. See the peptide storage guide for the full picture.
Common mistakes
- • The 1:1 mix. 2 mg in 2 mL makes a full dose 200 units. Use 1 mL.
- • Filling the barrel completely. A 100-unit draw leaves no room to correct for air.
- • Mixing a 2 mg vial for a 2 mg daily dose. That is a one-day vial; buy larger or accept nightly reconstitution.
- • Injecting after a meal. Not a mixing error, but it undercuts the point of the compound. Empty stomach, before bed.
- • Assuming the approved label's reconstitution applies to a compounded vial. Different presentation, different diluent, different in-use life.
Tesamorelin is FDA-approved as Egrifta for HIV-associated lipodystrophy, which makes it better studied than most peptides on this site, but approval is for that indication and not for general body-composition or anti-ageing use. Compounded tesamorelin sold outside that channel is not quality controlled, and stated strength, purity and sterility can be wrong. This page explains reconstitution mechanics only, not whether you should be using it. Tesamorelin affects growth hormone and IGF-1 and can affect glucose handling, so it warrants clinician oversight and bloodwork.
Skip the arithmetic
OptiPin's free reconstitution calculator takes your vial size, water volume and target dose and returns the exact units, flagging the draws that will not fit a syringe. The app then logs every injection, tracks what is left in the vial and warns you before it runs out or expires. iOS, on-device, no account.
Open the calculatorFrequently asked questions
How much bacteriostatic water for a 2 mg tesamorelin vial?
One millilitre. That gives 2 mg/mL, putting a 1 mg dose at 50 units and a full 2 mg dose at exactly 100 units, both within a single U-100 syringe. Adding 2 mL is the common mistake: it makes a 2 mg dose 200 units, which needs two injections.
How many units is 1 mg of tesamorelin?
With a 2 mg vial in 1 mL of bacteriostatic water (2 mg/mL) it is 50 units. With a 5 mg vial in 1 mL (5 mg/mL) it is 20 units. With the 1 mg/mL mix that comes from putting 2 mL into a 2 mg vial it is a full 100 units. Compute from your own concentration.
Why does my tesamorelin dose not fit in one syringe?
You almost certainly mixed 2 mg into 2 mL, giving 1 mg/mL. At that concentration a 2 mg dose needs 2 mL, which is 200 units and twice the capacity of a U-100 syringe. Remix at 2 mg/mL or higher.
How long does a tesamorelin vial last?
At daily dosing, not long. A 2 mg vial is two days at 1 mg daily and one day at 2 mg daily. Compounded 5 mg and 10 mg vials give five to ten days. This is why the beyond-use date is rarely the limiting factor for tesamorelin, unlike weekly compounds.
Should tesamorelin be injected at night?
Nightly on an empty stomach is the conventional timing, because tesamorelin works by stimulating the body's own growth hormone pulse and that pulse is largest during early sleep. Its half-life is only about thirty minutes, so timing has more effect here than it would for a compound that lingers.
Sources & further reading
- Tesamorelin (Egrifta) - DailyMed label (approved indication, reconstitution and storage for the approved presentation).
- Bacteriostatic Water for Injection, USP - DailyMed label (multi-dose diluent).
- USP General Chapter <797> - Sterile Compounding (beyond-use dating).
U-100 syringe: 100 units = 1 mL. Vial strengths and fill volumes vary between suppliers, so always verify the stated strength on your own vial before calculating. This page is educational and is not medical advice.
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