18+ · Research Use Only · Not for Human Consumption
Research answer
What did the tesamorelin trials find?
In its phase 3 trials, first reported in 2007, tesamorelin reduced visceral abdominal fat measured by CT against placebo in adults with HIV and excess abdominal fat. As of 23 September 2026, that is the basis of its one US approval; smaller trials studied liver fat and cognition.
Primara Labs sells some of the compounds covered here. Every figure on this page links to its source and the date it was checked.
Updated 23 September 2026
01
Phase 3
In Tesamorelin phase 3 (Falutz, NEJM 2007), a phase 3 trial of tesamorelin in adults with HIV and abdominal fat accumulation (86% men) (n=412), the visceral adipose tissue was -15.2% on 2 mg over 26 weeks, against +5.0% on placebo (Falutz J et al. N Engl J Med 2007 (tesamorelin phase 3)).
In a pooled analysis of the two 26-week phase 3 trials (806 adults with HIV and excess abdominal fat), triglycerides fell 37 mg per decilitre on tesamorelin and rose 6 mg per decilitre on placebo.
02
Other trials
In a 12-month randomised, placebo-controlled trial of 61 people with HIV and fatty liver disease, with no phase stated, tesamorelin reduced liver fat fraction by an absolute 4.1 percentage points more than placebo.
In a 20-week phase 2 trial of 152 adults aged 55 to 87, some with mild cognitive impairment, the intent-to-treat analysis showed a favourable effect on a cognitive composite, mainly executive function; two later trials in other groups did not show a significant effect.
03
Side effects reported
The abstract reports that adverse events did not differ significantly between groups, but that more participants on tesamorelin withdrew because of an adverse event; it gives no rates.
In a 20-week phase 2 trial in older adults, mild adverse events were reported by 68% on tesamorelin against 36% on placebo.
In a 6-month trial of 50 people with HIV, fasting glucose rose 9 mg per decilitre on tesamorelin against 2 on placebo at 2 weeks; the difference was not significant at 6 months.
04
How it works
Tesamorelin is a synthetic analogue of growth hormone-releasing factor (GHRH 1-44). It acts on the pituitary to increase basal and pulsatile growth hormone secretion, which in turn raises IGF-1.
Sources
Where every figure comes from
- Falutz J et al. N Engl J Med 2007 (tesamorelin phase 3) · checked 23 September 2026
- Lancet HIV 2019 · checked 23 September 2026
- Arch Neurol 2012 · checked 23 September 2026
- Arch Neurol 2012 · checked 23 September 2026
- JAMA 2014 · checked 23 September 2026
Last reviewed 23 September 2026