Tesamorelin

What it is

Tesamorelin is a synthetic analogue of growth hormone-releasing factor (GHRF, also called GHRH), the hypothalamic peptide that signals the pituitary to release growth hormone [1]. It is the active ingredient in Egrifta, an FDA-approved prescription drug from Theratechnologies first approved on November 10, 2010 under BLA 022505 [5]. It is indicated for the reduction of excess abdominal fat in HIV-infected adults with lipodystrophy, a pattern of fat redistribution seen during antiretroviral therapy [1][7]. Three formulations have been approved: the original 1 mg vial, Egrifta SV (2 mg vial) and, since March 25, 2025, Egrifta WR, an 11.6 mg vial that is mixed once weekly and injected daily [1][6]. Egrifta WR and Egrifta SV are not substitutable for each other [1].

How it works

In laboratory tests tesamorelin binds and stimulates human GHRF receptors with a potency similar to the body’s own GHRF [1]. Acting on pituitary somatotroph cells, it stimulates the synthesis and pulsatile release of endogenous growth hormone, which is both anabolic and lipolytic, and this in turn raises IGF-1 and IGFBP-3 [1]. Because it works through the patient’s own pituitary rather than supplying growth hormone directly, the label contraindicates it in people whose hypothalamic-pituitary axis is disrupted by hypophysectomy, hypopituitarism, pituitary tumour or surgery, head irradiation or head trauma [1]. In clinical trials no clinically significant changes were seen in other pituitary hormones such as TSH, LH, ACTH or prolactin [1]. The drug’s absolute bioavailability after subcutaneous injection is less than 4 percent [1].

What the evidence shows

The pivotal evidence is a phase 3 trial of 412 HIV patients with abdominal fat accumulation randomized to daily subcutaneous tesamorelin 2 mg or placebo for 26 weeks [7][8]. Visceral adipose tissue on CT fell 15.2 percent with tesamorelin and rose 5.0 percent with placebo; triglycerides and the total-to-HDL cholesterol ratio also improved, IGF-I rose 81 percent, and glycemic measures did not differ significantly [7]. Patients who continued for 52 weeks kept the reduction in trunk fat, while those switched to placebo regained it [1]. The label sets limits: long-term cardiovascular safety has not been established, the drug is not indicated for weight loss because its effect on weight is neutral, and there is no evidence it improves adherence to antiretroviral therapy [1].

Regulatory status

Tesamorelin is an FDA-approved drug. Drugs@FDA lists the original approval of BLA 022505 on November 10, 2010 [5], and the original label of that date carries the same indication for excess abdominal fat in HIV-infected patients with lipodystrophy [4]. Egrifta SV, the 2 mg vial formulation, has a label revised in July 2019 [3]. On March 25, 2025 FDA approved supplement S-020, which provided a new formulation, a new multiple-dose presentation and a new manufacturing site; that product is marketed as Egrifta WR [6][1]. The approved use is specific to HIV-associated lipodystrophy in adults; the label states it is not indicated for weight loss management and that safety and effectiveness in pediatric patients have not been established [1]. Status verified September 24, 2026.

Half-life and what it means for a level curve

The reference half-life in STACK is 0.5 hours. The labels report several values, all short. After 14 consecutive days of subcutaneous 2 mg Egrifta, the mean elimination half-life was 26 minutes in healthy subjects and 38 minutes in HIV-infected patients [3][4]. After a single 1.28 mg dose of Egrifta WR in healthy subjects it was 11 minutes [1], and after a single 1.4 mg dose of Egrifta SV it was 8 minutes [3]. STACK uses 0.5 hours, roughly the repeated-dose range measured in the treated population, because that is the setting the simulator models; the difference between 8 and 38 minutes changes nothing meaningful on a daily curve. Peak plasma levels arrive at about 0.15 hours [1]. A level reaches about 97 percent of steady state after five half-lives, here about 2.5 hours, so there is no build-up between daily doses. STACK’s curve is an estimate from this published half-life, not a blood level.

Reported side effects

The most commonly reported adverse reactions in the label, at more than 5 percent, are arthralgia, injection-site erythema, injection-site pruritus, pain in extremity, peripheral edema and myalgia [1]. Injection-site reactions occurred in 25 percent of treated patients versus 14 percent on placebo during the first 26 weeks, and hypersensitivity reactions including pruritus, erythema, flushing, urticaria and rash occurred in 4 percent [1]. Fluid retention related to growth hormone can cause edema, arthralgia and carpal tunnel syndrome [1]. Glucose intolerance can develop: 5 percent of treated patients versus 1 percent on placebo reached an HbA1c of 6.5 percent or higher by week 26 [1]. The label also warns of raised IGF-1, which should be monitored, a possible increased risk of neoplasms, and increased mortality with growth hormone in acute critical illness [1]. Call your prescriber about any new symptom.

Storage and handling

Storage depends on the formulation, so follow the label for the product you were dispensed. Egrifta WR 11.6 mg vials are stored at room temperature, 20 °C to 25 °C, in the original box to protect from light; after mixing with the supplied bacteriostatic water the vial stays at room temperature, is used for daily injections for 7 days, then discarded, and must not be frozen or refrigerated [1][2]. Egrifta SV 2 mg vials are also kept at room temperature and protected from light, but the reconstituted solution is used right away and any remainder is thrown out [3]. Both labels say to inject into the abdomen and rotate sites, avoiding scar tissue, bruises and the navel [1][3]. STACK’s reconstitution calculator handles the volume arithmetic from your label; it does not suggest a dose.

What STACK tracks for it

STACK logs each tesamorelin dose in mg exactly as your prescriber wrote it, with the date, time and abdominal injection site, and draws an estimated level curve from the 0.5-hour reference half-life. Because the level clears within a few hours, the curve mainly shows whether you injected each day and when. STACK also tracks the label-recommended monitoring items you and your prescriber may want to watch: waist measurements or other fat-reduction markers, weight, blood glucose or HbA1c results you enter, IGF-1 results, injection-site reactions and side effects such as joint pain or swelling [1]. Vial inventory tracks the 7-day life of a mixed Egrifta WR vial and the 28-day life of the diluent bottle [1]. STACK never suggests a dose or a schedule.

The reference half-life in STACK

STACK's simulator and the app use 30 min for Tesamorelin: 8–38 minutes across labels; 26 min (healthy) and 38 min (HIV patients) after 14 daily doses; 11 min single dose (Egrifta WR); 8 min single dose (Egrifta SV). Measured in: healthy adults and HIV-infected adults, subcutaneous, after 14 consecutive daily doses of 2 mg Egrifta (1 mg/vial formulation).

Estimate only. Modelled from the published half-life you selected and the doses you logged — not a measured blood level. Do not use it to make medication decisions.

Free tools for Tesamorelin

Read next

Sources

Every URL below was fetched and checked on 2026-09-24. Bracketed numbers in the text link here.

1. LabelEGRIFTA WR (tesamorelin) for injection — Prescribing Information, revised 3/2025
2. LabelEGRIFTA WR — tesamorelin kit — DailyMed label
3. LabelEGRIFTA SV (tesamorelin for injection) — Prescribing Information, revised 07/2019
4. LabelEGRIFTA (tesamorelin for injection) — Prescribing Information, 11/2010
5. FDADrugs@FDA: BLA 022505 EGRIFTA (tesamorelin acetate)
6. FDABLA 022505/S-020 Supplement Approval letter, March 25, 2025 — FDA
7. TrialMetabolic effects of a growth hormone-releasing factor in patients with HIV (Falutz et al., NEJM 2007)
8. TrialTH9507 in Patients With HIV-Associated Lipodystrophy (NCT00123253)