Tesamorelin

What is tesamorelin?

Tesamorelin is a synthetic analog based on the 44-amino-acid sequence of human GHRH, GHRH(1-44). ^[3] A hexenoyl group added to the starting end of the molecule increases resistance to breakdown; a 2026 review gives its half-life as about 26–38 minutes. ^[9] The drug stimulates growth hormone release from the pituitary and raises the IGF-1 level in the blood. ^[1]

According to the EMA’s summary, growth hormone plays a role in regulating the formation and breakdown of fat tissue; through growth hormone release, tesamorelin is expected to increase the breakdown of intra-abdominal fat in patients with HIV lipodystrophy. ^[5] Lipodystrophy is a change in the distribution of body fat in some people living with HIV: fat is lost in some areas, and sometimes excess fat accumulates inside the abdomen. ^[5]

Sermorelin, a shorter GHRH analog acting through the same pathway whose license was withdrawn, and the long-acting unlicensed analog CJC-1295 are covered in separate guides: Sermorelin, CJC-1295.

Licensed use: HIV-associated lipodystrophy

The indication on the FDA label is a single sentence: reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy. In the same section, the label lists three limitations of use: ^[1]

• Long-term cardiovascular safety has not been established; in patients whose visceral fat does not decrease, the benefit and risk of continuing treatment should be reassessed.
• It has no indication for weight management, because it has a neutral effect on weight.
• There are no data supporting that it improves adherence to HIV drugs.

The first US approval dates from 2010; a new formulation of a different strength was approved in March 2025. ^[1] In Canada, Health Canada granted a license on April 29, 2014 (the drug identification numbers were cancelled in 2022 and 2023); the indication is limited to adult lipodystrophy patients who have received HIV treatment, with a waist circumference of ≥95 cm in men and ≥94 cm in women and an intra-abdominal fat area measured on computed tomography (CT) above 130 cm². ^[6]

What did the phase 3 trials show?

The basis of the license is two multicenter, double-blind, placebo-controlled trials in patients aged 18–65 with increased waist circumference and waist-hip ratio, fasting blood sugar below 150 mg/dL, and at least 8 weeks of stable HIV treatment. People with type 1 diabetes or type 2 diabetes on medication, a history of cancer, or pituitary insufficiency were not enrolled. ^[1]

Source: FDA label, intention-to-treat analysis. ^[1] In the NEJM publication of the first trial, visceral fat fell by 15.2% in the tesamorelin group and rose by 5.0% in the placebo group; triglycerides fell by 50 mg/dL and rose by 9 mg/dL with placebo. The frequency of adverse events did not differ significantly between groups, but more patients in the tesamorelin group left the trial because of adverse events. ^[2] In the pooled analysis of the two trials (806 people), subcutaneous abdominal fat did not change significantly; the treatment effect was −12.3% in triglycerides and −7.2% in the total/HDL cholesterol ratio, and patients’ distress about abdominal appearance decreased. ^[3] Health Canada’s decision summary, however, states that blood lipid results were inconsistent between the two main trials and that in one of the trials no blood lipid result differed significantly from placebo. ^[6] A 2026 meta-analysis including five RCTs found a mean difference of −27.71 cm² (CI −38.37 to −17.06) in visceral fat; there was no significant reduction in subcutaneous fat and body mass index (the abstract does not give how many trials were pooled for each outcome). ^[4]

What happens when the drug is stopped? At week 26, those in the tesamorelin group were re-randomized. In those switched to placebo, visceral fat over the following 26 weeks rose by 25 cm² (22%) in Trial 1 and 24 cm² (16%) in Trial 2; in those continuing tesamorelin, the change was 3 cm² and −11 cm². ^[1] That is, the effect lasts as long as the drug is continued.

Visceral fat is an intermediate endpoint (an imaging value measured by CT); the clinical meaning of these results was assessed differently among regulators. According to Health Canada’s decision summary, a reduction of at least 8% in visceral fat was considered clinically meaningful in the main trials; the summary also notes that this threshold is an arbitrary value set in 2005 at a lipodystrophy forum attended by industry, academia, and regulators. According to the same summary, Health Canada’s review unit wrote that the clinical benefit the reduction provides, for example for cardiovascular risk, was uncertain and initially responded negatively to the application; the license was granted after the opinion of a reassessment panel of external experts and measures for IGF-1 monitoring. ^[6] The EMA committee also wrote that the reduction was not shown to be meaningful in terms of a real health benefit for patients. ^[5]

Why did Europe not approve it?

On June 21, 2012, the applicant company notified the EMA’s Committee for Medicinal Products for Human Use (CHMP) that it was withdrawing its marketing authorization application. According to the EMA’s summary, at that time, based on two main trials of 816 patients, the committee was leaning toward an opinion that the drug could not be approved: ^[5]

• In clinical practice, it would be difficult to distinguish lipodystrophy-related abdominal fat from obesity-related fat; the evidence was not considered sufficient to support the proposal to limit use to visceral fat above 130 cm².
• No clinically meaningful health benefit had been shown for the reduction in visceral fat.
• The patients in the trials did not represent European HIV patients, who had a lower mean body mass index and abdominal fat.
• IGF-1 was elevated in a significant proportion of patients; because high IGF-1 may be associated with an increased cancer risk and worsening of diabetic eye disease, the committee regarded this as an important safety concern.
• While treatment was expected to be long term, no long-term safety data had been submitted.

The reason in the company’s withdrawal letter was likewise that the committee could not reach a favorable benefit-risk conclusion. ^[5] This is not a formal refusal decision but a withdrawal made during the committee’s negative preliminary opinion; as a result, there is no licensed tesamorelin in the European Union.

What has been studied in off-label areas?

Fatty liver

A randomized, double-blind trial conducted at two sites in the US and funded by the NIH enrolled 61 people with HIV and a liver fat fraction of at least 5% (30 tesamorelin, 30 placebo). At 12 months, the reduction in liver fat fraction versus placebo was an absolute −4.1 points (CI −7.6 to −0.7; p=0.018), and relative −37% from baseline; the proportion of patients whose liver fat fell below 5% was 35% and 4%. Fasting blood sugar and HbA1c did not differ between groups; injection site complaints were more frequent in the tesamorelin group. The authors note that new studies are needed for long-term liver tissue outcomes. ^[7] This is not evidence for fatty liver patients without HIV.

Cognitive function (Baker 2012)

A randomized, double-blind, placebo-controlled trial conducted in Seattle enrolled 152 adults aged 55–87 (66 of them had mild cognitive impairment); 137 completed the trial. Participants used tesamorelin or placebo every night for 20 weeks. ^[8]

• In the intention-to-treat analysis, a favorable effect on the composite cognitive score was found (p=0.03); the effect was similar in those with mild cognitive impairment and in healthy older adults. The effect was more marked in those who completed the trial (p=0.002).
• There was improvement in executive function (p=0.005); the difference in verbal memory was only at the trend level (p=0.08).
• IGF-1 rose 117% and stayed within the physiological range; body fat percentage fell by 7.4%. In those with mild cognitive impairment, fasting insulin rose 35% within normal limits.
• Adverse events were mild, but were reported by 68% in the tesamorelin group and 36% in the placebo group.

The trial was supported by the NIH/National Institute on Aging and the US Department of Veterans Affairs; the drug and placebo were provided free by the manufacturer. ^[8] It is a single medium-sized trial; the authors write that longer studies are needed, and the finding does not mean dementia prevention or treatment. ^[8]

Weight loss, muscle, performance, and anti-aging use

The FDA label explicitly states that tesamorelin is not indicated for weight management and has a neutral effect on weight; in the phase 3 trials, the 26-week weight difference was not significant versus placebo. ^[1] In sport and “biohacking” circles, tesamorelin is mentioned for improving body composition, “recovery,” reducing inflammation, or tissue healing. The 2026 review writes that these claims go beyond the outcomes measured in RCTs, that they should be treated as marketing narratives rather than established clinical effects, and that tesamorelin studies should not be generalized to muscle growth or athletic purposes. ^[9]

These uses are off-label. Tesamorelin sold online “for research purposes” is not the same product as the licensed drug: in an August 2026 warning letter, the FDA characterized tesamorelin sold this way as an unapproved new drug. According to the letter, despite the “for research use only” and “not for human consumption” statements on the labels, the claims on the website showed that the products were being sold for use in humans; the FDA stressed that injectable products carry a risk of serious harm because they bypass some of the body’s basic defenses against toxins and microorganisms. ^[10] The meaning of this label is covered in a separate guide: What does research peptide mean?

What are the risks?

The FDA label lists the following risks in licensed use: ^[1]

• Contraindications: hypothalamic-pituitary axis disorder, active cancer, hypersensitivity to tesamorelin or excipients, and pregnancy.
• Cancer: treatment of a pre-existing cancer must be completed and the disease inactive; the drug is stopped on signs of recurrence.
• IGF-1 elevation: in 47% of those using it for 26 weeks, IGF-1 was above 2 standard deviation scores (SDS), and in 36% above 3 SDS; in those using it for 52 weeks, the rates were 34% and 23%. The effects of prolonged IGF-1 elevation are unknown.
• Blood sugar: the proportion whose HbA1c rose to 6.5% or above at week 26 was 5% with tesamorelin and 1% with placebo; the risk of developing diabetes (HbA1c ≥6.5%) was higher than with placebo (intention-to-treat “hazard odds ratio” on the label 3.3; CI 1.4 to 9.6). Monitoring for retinopathy is recommended in those with diabetes.
• Fluid retention: edema, joint pain, and carpal tunnel syndrome can occur.
• Hypersensitivity and injection site reactions: hypersensitivity reactions occurred in 4% of patients; injection site reactions were 25% in the first 26 weeks versus 14% with placebo.
• Serious illness: because increased mortality has been reported with pharmacological amounts of growth hormone in acutely critically ill patients, discontinuing the drug is considered in critically ill patients.

The most common adverse effects (above 5%) are joint pain, redness and itching at the injection site, pain in the arms and legs, peripheral edema, and muscle pain. About half of patients developed antibodies to the drug; the visceral fat and IGF-1 response were similar in those with and without antibodies. ^[1] The meta-analysis also reports joint and muscle pain, tingling, and injection site redness. ^[4]

These safety data come from patients with HIV selected by specific exclusion criteria and under physician monitoring. In products obtained from an unsupervised supply chain, contents, purity, and dose are uncertain; the 2026 review stresses this as a general problem of the class. ^[9] General peptide side effects: Peptide side effects

FDA, EMA, WADA, and Türkiye: what is the legal status?

United States and Canada

In the US, tesamorelin has been a prescription drug since 2010, and its only indication is excess abdominal fat due to lipodystrophy in adults with HIV. ^[1] Use outside this indication is off-label; products sold with a “for research purposes” label are treated by the FDA as unapproved new drugs. ^[10] In Canada, a license with a similar indication was granted in 2014; according to Health Canada’s post-license activity table, the manufacturer discontinued sales and the drug identification numbers (DIN) of the two presentations were cancelled on September 30, 2022, and July 13, 2023. ^[6]

European Union

There is no licensed tesamorelin in the European Union; the application was withdrawn in 2012 during the CHMP’s negative preliminary opinion. ^[5]

Sport (WADA)

In WADA’s list effective from January 1, 2026, tesamorelin is named, together with CJC-1293, CJC-1295, and sermorelin, among GHRH and its analogs under the heading S2.2.4 “growth hormone releasing factors.” Substances in class S2 are prohibited at all times, in and out of competition, and none is a “specified substance.” ^[11] Researchers at the Türkiye Doping Control Center at Hacettepe University validated, according to WADA rules, and in 2026 published a mass spectrometry method that detects GHRH and its analogs such as sermorelin, tesamorelin, and CJC-1295 in urine for screening and confirmation purposes. ^[12]

Türkiye

No product with tesamorelin as the active ingredient is on the TİTCK (Turkish Medicines and Medical Devices Agency) Licensed Human Medicinal Products List dated October 16, 2026. ^[13] Article 19 of Law No. 1262 on Pharmaceutical and Medicinal Preparations (İspençiyari ve Tıbbi Müstahzarlar Kanunu) punishes with one to five years of imprisonment those who manufacture unlicensed preparations and those who knowingly sell, offer for sale, or have such manufactured preparations sold; importing preparations made abroad without a license for commercial purposes is treated as smuggling. ^[14]

The general legal framework for peptides: Are peptides legal?

Evidence table: claim, population, and limits

Limits of this guide

This page summarizes tesamorelin’s licensing information, published clinical trials, and decisions of official bodies. It gives no dose, preparation, administration technique, or product sourcing information; the administrations in the label and trials are prescribing information for physicians and descriptions of the trials. Abdominal fat accumulation, fatty liver, or memory complaints require evaluation of the cause by a physician.