Tesamorelin has a plasma half-life measured in minutes, while changes in visceral fat were followed over months. It is FDA-approved, as Egrifta SV and Egrifta WR, to reduce excess abdominal fat in adults with HIV-associated lipodystrophy [1]. Since March 23, 2020 FDA regulates it as a biologic, and biologic products cannot rely on the 503A or 503B compounding exemptions [8] [9]. The full status is in is tesamorelin FDA-approved.
The labels put the half-life at 8 to 11 minutes
Both current labels report a half-life in minutes, not hours. After a single injection in healthy adults, the mean half-life was 8 minutes for Egrifta SV and 11 minutes for Egrifta WR [1] [2]. Figures of 26 minutes or 2 to 3 hours that circulate online don't match either label.
| Measure | Egrifta SV | Egrifta WR |
|---|---|---|
| Mean half-life | 8 minutes | 11 minutes |
| Median time to peak level | 0.15 hours (about 9 minutes) | 0.15 hours (about 9 minutes) |
| Absolute bioavailability | Under 4% (measured with the original 1 mg/vial formulation) | Same study, cited on both labels |
| Prescribing information revised | February 2024 | March 2025 |
| Interchangeable? | No: the labels say the two are not substitutable | No |
Sources: Egrifta SV and Egrifta WR prescribing information, section 12.3, DailyMed. Measured in healthy adults.
Under 4% bioavailability means most of an injected dose never reaches the bloodstream intact [1]. The label also notes that no formal studies of how the body breaks tesamorelin down have been done in people.
A short half-life still works because it triggers your own hormone
Tesamorelin doesn't need to stay in the blood to have an effect. It is a growth-hormone-releasing factor analog: it signals the pituitary to release the body's own growth hormone, which raises IGF-1. In the main 26-week trial of 412 people with HIV, IGF-1 rose 81.0% on tesamorelin and fell 5.0% on placebo [3].
That downstream signal, not the drug itself, is what lasts. The same trial found visceral fat fell 15.2% on tesamorelin while it rose 5.0% on placebo [3]. Whether that counts as "working" for other goals is covered in does tesamorelin work.
The belly-fat effect fades over the six months after stopping
Stopping tesamorelin lets visceral fat come back. In the label's extension phases, people who had taken tesamorelin for 26 weeks were re-randomized to keep taking it or switch to placebo for another 26 weeks [1]. Those who switched regained fat; those who stayed on held steady.
| Group | Study 1 | Study 2 |
|---|---|---|
| Kept taking tesamorelin | 0% (+0.5 sq in / +3 cm²), 154 people | -5% (-1.7 sq in / -11 cm²), 92 people |
| Switched to placebo | +22% (+3.9 sq in / +25 cm²), 50 people | +16% (+3.7 sq in / +24 cm²), 85 people |
| Difference | -3.4 sq in (-22 cm²) | -5.4 sq in (-35 cm²) |
Source: Egrifta SV label, Table 4 (intent-to-treat, last observation carried forward).
A pooled analysis of both trials found that people kept on the drug for 52 weeks were still 17.5% below their starting visceral fat [4]. These results describe benefit maintained through the studied 52 weeks; they do not guarantee continued benefit indefinitely or predict an individual reversal schedule.
Label fluid retention is temporary or ends when treatment stops
The label gives no day count for fluid retention, but it says how it ends. Section 5.3 links it to the release of growth hormone and describes the course [1]:
This manifests as increased tissue turgor and musculoskeletal discomfort resulting in adverse reactions (e.g. edema, arthralgia, and carpal tunnel syndrome) which are either transient or resolve with discontinuation of treatment.[1]
If swelling or joint pain doesn't settle, your prescriber decides what to do next; don't stop or adjust on your own. The same growth-hormone effect is why FDA expects fluid retention with unapproved peptides, covered in does ipamorelin cause water retention. Full side-effect rates are in is tesamorelin safe.
WADA bans it, and labs can test urine for it
Tesamorelin is prohibited in sport at all times. WADA's Prohibited List names it under S2.2.4, growth hormone releasing factors, alongside CJC-1295 and sermorelin [7].
A 2021 study built a urine test for four of these analogs, tesamorelin included, with detection limits generally 1 ng/mL or less in fortified urine, described by the authors as meeting the then-applicable WADA target [6]. The authors noted these analogs did not appear to have been found in anti-doping samples so far. That laboratory method does not establish a detection window after administration in people.
A small population model found no clinically relevant covariates
A population model of 38 patients with HIV and healthy volunteers found age, body size, race and health status were not statistically related to the pharmacokinetic parameters within the ranges studied [5]. The label adds one difference: total exposure was 34% higher in people with HIV than in healthy adults, while peak levels were similar [1].
How prescribers schedule it is covered in how to take tesamorelin, and how the vials should be kept in does tesamorelin need to be refrigerated. How this site reads a label is set out in how we check.