What the trials dosed
Three trials carry the human data behind the number. In the 2007 New England Journal of Medicine trial, 412 patients with HIV and abdominal fat accumulation received 2 mg of tesamorelin or placebo by daily subcutaneous injection for 26 weeks. Visceral adipose tissue on CT fell 15.2% on tesamorelin and rose 5.0% on placebo; triglycerides fell 50 mg/dL versus a 9 mg/dL rise; IGF-1 rose 81.0% versus a 5.0% fall. Adverse events did not differ significantly between groups, but more patients on tesamorelin withdrew because of one, and glycemic measures did not differ.
The 2010 pooled analysis of two phase 3 trials, 806 patients, used the same 2 mg daily dose. At week 26 the treatment effect on visceral fat was minus 15.4%, with no significant change in abdominal subcutaneous fat, triglycerides down 12.3% and the cholesterol to HDL ratio down 7.2% versus placebo, and IGF-1 up a mean 108 ng/mL. Patients re-randomized to stay on tesamorelin for a second 26 weeks held their visceral-fat loss at 17.5% from baseline; the abstract does not report what happened in the group switched to placebo. Glucose parameters showed no clinically meaningful differences at 26 or 52 weeks.
The 2014 JAMA trial randomized 50 HIV-infected adults to 2 mg daily or placebo for six months. Visceral fat fell a mean 34 cm2 versus an 8 cm2 rise on placebo, and liver fat fell as well, a net treatment effect of minus 2.9% in lipid-to-water percentage. Fasting glucose rose by a treatment effect of 7 mg/dL at two weeks and was not significantly different at six months.
Every one of those patients had HIV-associated lipodystrophy. That is the population the number was established in.
What the label says
Tesamorelin is FDA-approved as Egrifta for the reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy. Two formulations are on the market with different recommended doses: Egrifta SV, 1.4 mg once daily (0.35 mL of the reconstituted solution), and Egrifta WR, 1.28 mg once daily (0.16 mL). Both labels state that long-term cardiovascular safety has not been established, both instruct the prescriber to monitor IGF-1 during therapy, and both list the same contraindications: disruption of the hypothalamic-pituitary axis, active malignancy, known hypersensitivity, and pregnancy. Those are the sentences a calculator does not contain.
The arithmetic
Milliliters equal the prescribed milligrams divided by the concentration in milligrams per milliliter. Units on a U-100 insulin syringe equal milliliters times 100. Worked through for the 2 mg trial dose: from a vial reconstituted to 5 mg/mL, 2 mg is 0.4 mL, which is 40 units; from a vial at 2 mg/mL, 2 mg is 1.0 mL, which is 100 units; from a vial at 10 mg/mL, 2 mg is 0.2 mL, which is 20 units. Same dose, three different unit counts, because the concentration differs. A units figure quoted without its concentration is meaningless.
Reconstitution sets the concentration
Compounded tesamorelin usually ships as a lyophilized powder that is reconstituted with bacteriostatic water, and the concentration is whatever the powder mass divided by the water volume makes it. A 10 mg vial reconstituted with 2 mL is 5 mg/mL; with 1 mL it is 10 mg/mL. Every unit count downstream depends on that choice, which is why a prescription comes with reconstitution instructions and why copying a units number from a forum, where the vial size and the water volume are unstated, produces the wrong dose more often than the right one. The label of an FDA-approved product fixes the concentration; a compounded vial does not until it is reconstituted.
What a calculator cannot tell you
Whether tesamorelin belongs in your plan. The evidence is in HIV-associated lipodystrophy; use for body composition outside that indication is off-label, and the tesamorelin peptide guide covers what the off-label evidence does and does not show. Whether your IGF-1 and glucose are being followed: the label says monitor IGF-1, and the trials tracked glucose because a GHRH analog raises GH. Whether a contraindication applies. Whether a different GHRH analog fits better, which is the question the tesamorelin vs sermorelin guide answers, with the sermorelin dosage guide alongside it. Those are clinician decisions, made with your history and labs in front of them.
How the growth hormone lane works at PepScribe
Tesamorelin is a prescription medication. Compounded tesamorelin is not FDA-approved. At PepScribe, growth hormone and body composition goals run through the Growth Hormone & Body Composition program: a free online visit, a US-licensed clinician who reviews your history, and a plan the clinician writes. If a medication is prescribed, it is compounded in the USA by a licensed 503A pharmacy and shipped to you with dosing instructions. The clinician decides which compound, at what dose, with what monitoring; the arithmetic above is for reading the instructions you are given, not for writing them.
Frequently asked questions
What is the tesamorelin dose used in clinical trials?
2 mg by subcutaneous injection once daily, in the 412-patient NEJM trial, the 806-patient pooled phase 3 analysis, and the 50-patient JAMA trial, all in HIV-infected adults with abdominal fat accumulation.
What is the FDA-approved dose of tesamorelin?
Egrifta SV is 1.4 mg once daily (0.35 mL reconstituted); Egrifta WR is 1.28 mg once daily (0.16 mL). Both are approved only for excess abdominal fat in HIV-infected adults with lipodystrophy.
How many units is 2 mg of tesamorelin?
It depends on the concentration: 40 units from a 5 mg/mL vial, 100 units from a 2 mg/mL vial, 20 units from a 10 mg/mL vial. Milliliters equal mg divided by mg/mL; units on a U-100 syringe equal milliliters times 100.
How do I reconstitute a 10 mg vial?
The concentration is the powder mass divided by the water volume: 2 mL of bacteriostatic water makes 5 mg/mL, 1 mL makes 10 mg/mL. Follow the pharmacy's instructions; the volume they specify is what makes the prescribed units correct.
Does tesamorelin need blood monitoring?
The label instructs monitoring IGF-1 during therapy, and the trials tracked fasting glucose, which rose transiently at two weeks in the JAMA trial and was not different at six months. A clinician orders and reads those labs.
Is tesamorelin FDA-approved for fat loss?
It is FDA-approved for the reduction of excess abdominal fat in HIV-infected adults with lipodystrophy. Use for body composition outside that indication is off-label, and compounded tesamorelin is not FDA-approved.
