What is tesamorelin?

What it does in the body

Tesamorelin works on the same switch as the body’s own GHRH, a receptor on the pituitary, and it presses that switch about as hard. The label puts it this way:

The receptor sits on the pituitary cells that make growth hormone. GHRH, in the label’s words, is “a hypothalamic peptide that acts on the pituitary somatotroph cells to stimulate the synthesis and pulsatile release of endogenous growth hormone (GH), which is both anabolic and lipolytic”.¹ Growth hormone in turn raises IGF-1, a growth factor made in the liver and other tissues, and IGF-1 is one of the numbers the trials tracked. The anabolic half of that sentence is why people ask whether it builds muscle, which its trials answer only in part.

Visceral fat is the deep layer packed around the organs, measured in these trials by a CT slice at the lower back, and it fell while the weight on the scale barely moved.¹ Other pituitary hormones, ACTH and prolactin among them, showed no clinically significant change.¹ Ipamorelin gets to growth hormone through a different receptor altogether, and the two routes to the same hormone are compared side by side.

What it's approved for, and in whom

The fat in question is the kind that builds up during HIV treatment. The first of the two approval trials, published in 2007, opens on exactly that point: “Visceral adipose tissue accumulates during antiretroviral therapy in many patients who are infected with the human immunodeficiency virus (HIV); this process is associated with an increased cardiovascular risk.”³

So the evidence comes from a specific group of people. The two approval trials enrolled adults aged 18 to 65, all on stable HIV treatment and all with a large waist: at least 95 cm for men and 94 cm for women. Men made up 86% and 84% of the two trials, and the average age in both was 48. Fasting blood sugar had to be under 150 mg/dL, and anyone with a history of cancer was kept out.¹

The label draws its own limits around that use. It isn’t for weight loss, long-term heart safety hasn’t been established, and it’s ruled out in pregnancy, in anyone with active cancer, and in anyone whose pituitary has been disrupted by surgery, a tumor, head radiation or head injury.¹ The label’s full list of warnings, cancer included, is on is tesamorelin safe.

How long it lasts: three labels, three numbers

Minutes, on all three labels. Tesamorelin clears fast enough that the daily injection has nothing to do with keeping a level up:

EGRIFTA, 2010 label

26 minutes in healthy subjects and 38 in patients with HIV, after 14 days of daily doses⁴

EGRIFTA SV, 2024 label

8 minutes in healthy subjects, after one 1.4 mg dose¹

EGRIFTA WR, 2025 label

11 minutes in healthy subjects, after one 1.28 mg dose²

The first row is where the “26 to 38 minutes” you’ll see elsewhere comes from, and it isn’t a range. The label gives 26 minutes for healthy subjects and 38 for patients with HIV: two averages for two groups of people, each measured “after subcutaneous administration for 14 consecutive days”.⁴ Nobody measured a spread running from one to the other.

Even on the longest of those figures, 38 minutes, five half-lives pass in a little over three hours, and five half-lives leave about 3% of a dose. A once-a-day injection isn’t keeping a level topped up. It works through what it sets off, and at week 26 IGF-1 was still more than 100 ng/mL above where it started.¹ The half-life calculator does the same arithmetic for any interval, and the matrix on the home page sets all five molecules on one axis, from minutes out to the 5.8–8.1 days of the long-acting form of CJC-1295.

The approved product, and what sellers list

The approval belongs to a product, not to the molecule on any shelf. EGRIFTA SV and EGRIFTA WR are made by Theratechnologies and sold on prescription, and every trial figure on this page comes from EGRIFTA.¹

Both sellers here that price tesamorelin describe what they dispense as compounded. Longevixx prints “Compounded in a U.S. pharmacy” under the listing, and ElitePhysiqMD’s peptide page carries a notice that reads “Peptide therapies are compounded medications not FDA-approved as finished drug products.” Same name on the menu, different product in the vial.

Both pages were captured in September 2026. Each seller’s figures, with the day they were read, are on its record: Longevixx and ElitePhysiqMD.

On price, the sellers that list it are on the board on the home page with every figure’s billing cycle and reading date, and tesamorelin vs ipamorelin covers the pairing some of them sell.

Questions that come next

Sources