Tesamorelin

Tesamorelin (This is not a product description, disclaimer at the bottom of the page)

Tesamorelin is a laboratory version of a hormone that naturally helps the body release growth hormone. It was approved by the FDA in 2010 for the treatment of a condition called HIV-associated lipodystrophy [1, 2]. This condition causes an unhealthy build-up of deep abdominal fat in people living with HIV who are taking antiretroviral drugs. Tesamorelin is marketed under the name Egrifta SV and manufactured by a company in Canada. It is currently the only drug approved for the reduction of this type of fat in HIV-infected individuals. Structurally, tesamorelin is a stabilised 44-amino acid analogue of human GHRH, with a slight chemical modification (trans-3-hexenoic acid group) at the N-terminus to increase its stability and bioavailability [1, 3]. Following subcutaneous injection, tesamorelin binds to GHRH receptors in the pituitary gland and stimulates the release of natural growth hormone (GH), which in turn increases insulin-like growth factor-1 (IGF-1) levels. IGF-1 helps mediate many of the positive effects of GH, such as promoting fat breakdown, regulating blood sugar levels and promoting tissue growth and repair. Tesamorelin has been shown to reduce deep abdominal fat and improve overall metabolism in HIV-infected individuals. Although it is mainly used for this purpose, researchers are also investigating it as a potential treatment for other conditions such as obesity, insulin resistance, cognitive impairment and hepatic steatosis [1-3]. One of the positive features of tesamorelin is that, although it affects fat and sugar metabolism, it has not been linked to liver damage or serious liver-related side effects. The recommended dose of tesamorelin is 2 mg daily by subcutaneous injection. It is generally well tolerated, although some users may experience mild side effects such as injection site reactions, muscle or joint pain or fluid retention. As with other therapies affecting growth hormone and IGF-1 levels, tesamorelin should be used with caution in patients with a history of malignancies. Periodic monitoring of IGF-1 levels during treatment is recommended.

Health benefits of Tesamorelin (based on human studies)

Clinical studies have shown that tesamorelin not only reduces visceral fat, but also significantly reduces liver fat and inflammation in people with HIV-related non-alcoholic fatty liver disease (NAFLD). Research by Fourman, Stanley and others has shown that tesamorelin can improve mitochondrial function, reduce the risk of fibrosis and down-regulate inflammatory and cancer-related genes in the liver. In addition to its effects on liver fat, tesamorelin has shown the ability to improve muscle quality, support cardiovascular health by reducing triglycerides and improving cholesterol profiles, and even improve aspects of cognitive function in the elderly. Importantly, tesamorelin maintains a strong safety profile, with minimal effects on blood sugar regulation, making it a potential option for long-term metabolic support in vulnerable populations.

Tesamorelin reduces body fat and improves liver health

In a carefully controlled study, Fourman et al (2020) tested tesamorelin (2 mg daily) for 12 months in 61 people who had both HIV and fatty liver disease (also known as non-alcoholic fatty liver disease or NAFLD) [4]. They wanted to see if tesamorelin could help reduce liver fat and prevent liver damage. Participants taking tesamorelin experienced a significant reduction in liver fat compared to those taking placebo (treatment without active drug). Tesamorelin also slowed the progression of liver fibrosis, meaning the liver was less scarred - a sign of better liver health. In addition, tesamorelin improved the function of certain liver genes. In particular, it increased the activity of genes responsible for breaking down fats and increasing energy (mitochondrial function). It also decreased the activity of genes that cause inflammation, uncontrolled tissue repair and cell growth - processes that can otherwise lead to liver damage and even cancer Importantly, tesamorelin has also been shown to affect genes in a way that may reduce the risk of liver cancer (hepatocellular carcinoma) [4]. This study suggests that by using tesamorelin to amplify natural growth hormone signals, we can significantly reduce fatty liver and possibly reduce the risk of scarring and liver cancer in people with HIV and NAFLD. In another 2017 study. Fourman et al analysed data from two phase III clinical trials involving 806 HIV-infected adults [5]. They investigated whether visceral fat reduction with tesamorelin could improve liver enzymes, markers of liver health. Participants with elevated baseline liver enzymes (ALT and AST) who achieved at least an 8% reduction in visceral fat showed significant improvements in these liver markers. Specifically, ALT decreased by approximately 8.9 U/L and AST decreased by approximately 3.8 U/L compared to a slight increase in those who did not significantly lose visceral fat. It is noteworthy that the improvement in liver enzymes persisted even after some participants discontinued tesamorelin and partially regained visceral fat. These results suggest that effective visceral fat reduction with tesamorelin may have a positive impact on liver health, highlighting the importance of visceral fat reduction in the treatment of HIV-related liver complications. Similarly, Stanley et al (2019) conducted a randomised double-blind study involving 61 participants with HIV who also had hepatic steatosis, confirmed by high liver fat levels (at least 5%) [6]. Participants received tesamorelin (2 mg daily) or placebo for 12 months. All then received tesamorelin for an additional 6 months to further observe the effects. Those treated with tesamorelin showed a significant decrease in liver fat. On average, liver fat decreased by approximately 4.1%, translating to a 37% reduction from initial fat levels. After 12 months, 35% of those taking tesamorelin achieved healthier liver fat levels (below 5%), while only 4% of those taking placebo achieved this result. Importantly, tesamorelin had no negative effect on blood sugar levels or glucose control. These results show that tesamorelin can be a very effective and safe drug to reduce liver fat levels in people with HIV-related steatohepatitis.

Tesamorelin reduces abdominal and liver fat in people with HIV

In another study, Stanley et al (2014) conducted a 6-month trial involving 50 adults with HIV who had increased abdominal fat due to taking HIV medication [7]. They tested whether daily injections of tesamorelin (2 mg/day) could effectively reduce abdominal and liver fat. Participants were divided into two groups: 28 received tesamorelin and 22 received placebo. Participants treated with tesamorelin had an average decrease in deep abdominal fat of approximately 34 cm², compared to an increase of 8 cm² in the placebo group. Furthermore, tesamorelin-treated participants showed a significant median decrease in liver fat percentage (-2.0%) compared to a small increase (+0.9%) in the placebo group. For HIV-infected individuals struggling with increased abdominal fat, tesamorelin significantly improved both abdominal and liver fat levels without causing long-term blood sugar problems. Falutz et al (2010) also conducted a one-year study involving 404 HIV-positive adults experiencing abdominal obesity due to taking HIV medication [8]. Participants received tesamorelin (2 mg daily injection) or placebo. They found that after 6 months, tesamorelin significantly reduced the amount of deep abdominal fat by approximately 11% (a reduction of 21 cm²), compared with almost zero change in the placebo group. Importantly, participants also saw a reduction in waist circumference and an improvement in waist-to-hip ratio, with no negative effect on limbs or superficial fat. Despite the increase in IGF-1 hormone levels, tesamorelin did not negatively affect glucose control, meaning that blood sugar levels remained stable. Importantly, participants reported feeling less anxious about their abdominal appearance, indicating psychological benefits. Interestingly, a 18% reduction in abdominal fat was observed after one year of continuous tesamorelin use. Participants who discontinued tesamorelin quickly regained abdominal fat [8], highlighting the importance of continuous treatment to maintain benefits. These results confirm that tesamorelin was effective in reducing harmful belly fat and improving body image without causing problems with blood sugar control. The therapy was safe and well tolerated, making it a good treatment option for HIV-infected people struggling with abdominal obesity. Similarly, in 2010. Falutz et al. again conducted a comprehensive analysis combining the results of two large international studies to assess how well tesamorelin reduces unhealthy abdominal fat (known as visceral adipose tissue or VAT) in HIV-infected people on antiretroviral therapy (ART) [9]. A total of 806 participants received tesamorelin 2 mg daily or placebo for 26 weeks. The results showed that those treated with tesamorelin experienced a significant mean decrease in VAT of approximately 15.4% compared to the placebo group. This reduction corresponded to an improvement in body shape and less anxiety related to the appearance of the abdomen, as confirmed by the assessments of both patients and their physicians. In addition, tesamorelin improved the lipid profile, specifically reducing triglyceride levels by approximately 12.3% and the cholesterol-to-HDL ratio by approximately 7.2%. While insulin and glucose levels remained stable, indicating no negative effect on blood sugar control [9]. The positive effects on VAT, waist circumference and lipids were maintained for up to 52 weeks in those who continued to take tesamorelin. Importantly, the treatment was generally well tolerated, which supports its long-term use. These findings highlight the potential of tesamorelin to safely reduce harmful abdominal fat and associated metabolic risk in people living with HIV, significantly improving their overall health and self-esteem. Furthermore, Mangili et al (2015) analysed data from two large clinical trials involving 806 HIV-positive adults who had excess abdominal fat [10]. Participants were treated with tesamorelin (2 mg daily) or placebo for six months. The results showed that tesamorelin significantly reduced visceral (deep abdominal) fat in the entire study population. Interestingly, some groups benefited more than others. Participants with metabolic syndrome, those with high cholesterol, elevated blood pressure and obesity, reported greater fat reduction. Those with high triglyceride levels, and those who identified themselves as white, also experienced greater benefits. Additionally, those taking tesamorelin were almost four times more likely to reduce visceral fat below 140 cm², a threshold associated with lower heart disease risk. These results indicate that tesamorelin is particularly effective in reducing harmful abdominal fat in HIV-infected individuals, especially those with certain metabolic risk factors. In addition, Falutz et al (2008) conducted a long-term study involving 410 HIV-infected adults with excess abdominal fat caused by medication [11]. Initially, participants received tesamorelin (2 mg daily) or placebo for 26 weeks. They then continued taking tesamorelin, switched from placebo to tesamorelin or discontinued tesamorelin to assess long-term effects at one year. They found that those who took tesamorelin continuously for 52 weeks maintained 18% reduction in abdominal fat. Furthermore, participants who discontinued tesamorelin saw a rapid return of abdominal fat, indicating that continuous use is necessary to maintain the benefits. Tesamorelin also improved triglyceride levels and overall cholesterol levels, which is beneficial for heart health. Importantly, Tesamorelin was safe and had no adverse effects on blood sugar levels in the long term [11]. These results show that Tesamorelin provides a sustained reduction in harmful belly fat and improves blood fat levels without negatively affecting blood sugar levels. However, treatment must be continued long-term to maintain these benefits. Mateo et al (2011) reviewed the use of tesamorelin in the treatment of HIV-associated lipodystrophy, a condition involving abnormal fat distribution [12]. HIV-infected patients often experience excess fat around the abdomen (visceral fat), while losing healthier fat just below the skin (subcutaneous fat). These body changes not only negatively affect appearance and self-esteem, but can also increase the risk of heart disease and other metabolic problems. Tesamorelin, administered by daily injections, specifically reduces visceral fat while retaining mainly subcutaneous fat. In addition to improving the appearance of the abdomen and reducing body image anxiety, tesamorelin was also found to positively reduce triglyceride levels. Importantly, the treatment did not significantly affect blood sugar or insulin levels. However, the researcher reported that these improvements only lasted as long as the drug was continued, suggesting the need for ongoing treatment to maintain the benefits. These results confirm that tesamorelin is a safe and effective therapy to help HIV-positive people manage problematic belly fat, improve metabolic health and improve overall quality of life. Also in another study Falutz et al (2007) evaluated. The researchers measured abdominal fat (visceral adipose tissue, VAT) and cholesterol levels [13]. They found that tesamorelin (2 mg/day injections) in 412 HIV-infected adults reduced approximately 15% of harmful abdominal fat over 26 weeks. In comparison, those taking placebo gained weight. It is worth noting that triglyceride levels dropped significantly and the balance between total cholesterol and 'good' HDL cholesterol improved. In addition, tesamorelin did not adversely affect blood sugar levels or insulin control. These results suggest that tesamorelin effectively reduces dangerous belly fat and improves cholesterol levels, potentially lowering the risk of heart disease without harming glucose metabolism. Furthermore, Rahman et al (2023) analysed data from a phase III study involving HIV-infected individuals who received tesamorelin (2 mg/day) for 26 weeks [14]. Participants were divided into two groups: those with and without excess fat in the upper back known as the 'buffalo hump'. Both groups significantly reduced visceral fat (by approximately 8%). These results demonstrate the consistent efficacy of tesamorelin regardless of the presence of dorsal-chest fat. It is noteworthy that waist circumference and trunk fat improved similarly in both groups as lean body mass increased. Although there were small differences in changes in subcutaneous adipose tissue, the overall benefits were consistent. These results confirm that tesamorelin is equally beneficial in reducing unhealthy abdominal fat in people with HIV, regardless of whether they also have a 'buffalo hump'. Furthermore, in 2005. Falutz et al. conducted a 12-week randomised, placebo-controlled trial involving 61 HIV-infected patients with abdominal obesity [15]. Participants received placebo, tesamorelin 1 mg or tesamorelin 2 mg daily. Both doses effectively increased insulin-like growth factor 1 (IGF-1), a metabolically beneficial hormone, by 48% and 65%, respectively, compared with placebo. The 2 mg dose significantly reduced trunk fat by approximately 9.2%, compared to a moderate reduction of 4.6% at the lower dose [15]. It is worth noting that visceral fat, the deep abdominal fat closely associated with health risks, decreased by about 15.7% at the higher dose. Subcutaneous fat, the healthier layer just below the skin, remained stable, and the ratio of visceral to subcutaneous fat improved in both tesamorelin groups. Importantly, lean body mass increased in participants taking tesamorelin. Lipid profiles improved, with significant decreases in triglycerides and cholesterol/HDL cholesterol ratio, while fasting blood sugar levels remained unchanged [15]. These results show that tesamorelin was safe for reducing harmful abdominal fat and improving metabolic health without compromising blood sugar control.

Tesamorelin helps improve muscle quality and quantity in people with HIV

In the study, Adrian et al (2019) analysed data from two previous clinical trials to see if tesamorelin could also help improve muscle health in people with HIV who had excess abdominal fat [16]. Specifically, they studied participants who had significant abdominal fat loss (at least 8%) after taking tesamorelin (2 mg daily) for 26 weeks. They compared these 'responders' (193 people) with a placebo group (148 people), using CT scans to measure changes in muscle. They found that Tesamorelin significantly improved muscle density (quality) in all four torso muscle groups tested. Density increased by 1.56 to 4.86 units compared to placebo, indicating healthier muscle tissue Tesamorelin also increased muscle size (area) in all muscle groups, adding approximately 0.64 to 1.08 cm² compared to placebo, suggesting improved muscle strength [16]. In particular, the rectus (abdominal) and psoas (deep lower back) muscles showed a significant increase in total muscle area (approximately 0.44 to 0.46 cm²). In addition, the abdominal muscle groups showed increased density. These findings suggest that tesamorelin not only helps reduce unhealthy abdominal fat, but also improves muscle health by increasing muscle size and density.

Tesamorelin improves cellular energy in obese adults

Tesamorelin can improve cellular energy in people with low growth hormone levels. Makimura et al (2014) conducted a 12-month study involving 39 obese adults who had low growth hormone (GH) levels [17]. Participants were given tesamorelin (a growth hormone-releasing drug) or a placebo to see if raising IGF-I levels could improve mitochondrial function (how efficiently cells produce energy). The researchers found that those taking tesamorelin had a significant increase in IGF-I levels compared to the placebo group (+102.9 µg/L vs. +22.8 µg/L). Furthermore, higher IGF-I levels correlated strongly with better mitochondrial function, meaning that cells became more efficient in energy production. This correlation was particularly strong among participants treated with tesamorelin. These results suggest that tesamorelin may increase cellular energy production in obese adults with low GH levels by increasing IGF-I. Improved mitochondrial function may lead to improved overall metabolic health and energy levels, which is particularly important for obese individuals.

Tesamorelin improves blood lipid and blood sugar stability

In a study, Stanley et al (2012) analysed data from two phase III clinical trials involving adults with HIV-related abdominal fat accumulation [18]. Participants who experienced at least 8% of visceral fat reduction after taking tesamorelin for 26-52 weeks ('responders') were compared with those who did not achieve this reduction ('non-responders'). It was found that the 'responders', who reduced abdominal fat by at least 8%, experienced significant improvements in triglyceride (harmful blood fats) levels. In addition, the participants maintained stable blood sugar levels and haemoglobin A1c (HbA1c), a marker of long-term glucose control, showing that tesamorelin does not negatively affect diabetes risk. In addition, beneficial hormones such as adiponectin increased, helping to manage insulin sensitivity and reduce inflammation. These results suggest that achieving a significant reduction in abdominal fat (8% or more) with tesamorelin provides significant improvements in blood lipid levels, glucose stability and beneficial hormonal changes, highlighting its potential to improve long-term metabolic health.

Tesamorelin can lower harmful immune responses

In a study, Stanley et al (2021) studied 61 people living with HIV who also suffered from fatty liver disease (NAFLD) [19]. The participants took tesamorelin for one year. The researchers checked blood and liver tissue samples to see how tesamorelin affected immune activity. They found that tesamorelin significantly reduced markers associated with immune activity, especially those involving T cells and inflammatory cells. Furthermore, gene analysis showed that tesamorelin reduced inflammatory signals directly in the liver. These findings suggest that tesamorelin may help to reduce harmful immune responses, potentially protecting against inflammation-induced liver damage in people with HIV and hepatic steatosis.

Tesamorelin reduces heart disease risk in obese adults

Along with reducing abdominal fat, Tesamorelin may reduce the risk of heart disease in obese individuals. In a study by Makimura et al (2012), they assessed the effect of tesamorelin (2 mg daily) in 60 obese adults with naturally low growth hormone levels [20]. They found that tesamorelin users had a significant decrease in deep abdominal fat compared to placebo. In addition, users had better markers such as reduced arterial thickness, lower triglycerides and less inflammation (CRP levels). This study suggests that Tesamorelin may help reduce belly fat and cardiovascular risk factors, improving overall heart health in obese individuals without negatively impacting glucose control. In another study, Stanley et al (2011) conducted a study involving 410 adults living with HIV who had excessive abdominal fat [21]. Participants were given tesamorelin (2 mg daily) or placebo for 26 weeks to see if reducing deep abdominal fat (visceral adipose tissue or VAT) would also improve markers of inflammation and blood clotting (fibrinolysis). It turned out that participants who took tesamorelin had a significant reduction in abdominal fat. Fat loss was associated with better inflammatory profiles and improved markers related to blood clotting, such as lower levels of tissue plasminogen activator (tPA) - a substance associated with blood clotting risk. Furthermore, greater reduction in abdominal fat was associated with lower levels of harmful clotting substances and higher levels of beneficial hormones, such as adiponectin, important for healthy metabolism and inflammation control. These results show that tesamorelin can effectively reduce harmful abdominal fat, which may also help to reduce inflammation and the risk of blood clots. This improvement may benefit overall cardiac and metabolic health, particularly in people with HIV who have a higher cardiovascular risk. In addition, Grinspoon et al (2025) combined data from two phase III clinical trials involving 543 HIV-infected adults with excess abdominal fat [22]. After 26 weeks of daily use of tesamorelin (2 mg), participants showed a small but significant reduction (by approximately 0.40%) in the predicted 10-year risk of cardiovascular disease. This improvement was particularly noticeable in those already at higher cardiovascular risk. The reduction in cardiovascular risk was mainly due to improvements in cholesterol levels, despite the fact that almost half of the participants were already using cholesterol-lowering medication. These results highlight the potential of tesamorelin to reduce the risk of heart disease in people with HIV by effectively lowering harmful visceral abdominal fat and improving the cholesterol profile.

Tesamorelin improves fat distribution

Russo et al (2024) investigated how tesamorelin may help people taking integrase inhibitors (INSTIs), a common HIV therapy associated with fatty tissue changes [23]. The study involved 61 participants with HIV and liver fat problems, 38 of whom were taking INSTIs. Of these, 15 took tesamorelin (2 mg daily) and 16 received placebo for 12 months. Those taking tesamorelin reported a significant reduction in deep abdominal fat (visceral fat), with an average loss of 25 cm², compared to an average gain of 14 cm² in the placebo group. Tesamorelin users showed a significant reduction in liver fat with an average of 4.2%, compared to only 0.5% in the placebo group. There was also a slight improvement in the balance between trunk fat (chest and abdomen) and limb fat, helping to achieve a healthier body composition. Furthermore, Tesamorelin proved to be safe, without worsening blood sugar control. The incidence of side effects, including blood sugar issues, was similar in both the tesamorelin and placebo groups. This study confirms that tesamorelin is effective in reducing abdominal and liver fat in HIV-infected people on INSTI-based therapy. It provides important evidence that, even for those experiencing HIV drug-induced weight changes, tesamorelin remains a safe and beneficial option for improving overall body composition.

Tesamorelin improves cognitive function in older people

In a 20-week randomised, double-blind, placebo-controlled study by Baker et al (2012), researchers examined how tesamorelin affected memory and thinking skills in 152 older adults [24]. This study included both healthy participants (86 people) and people experiencing mild cognitive impairment (MCI, 66 people). The study assessed multiple aspects of cognitive performance, including executive function (skills related to planning, organisation and decision-making), verbal memory and visual memory. The results of this study showed significant improvements in overall cognitive performance among those receiving tesamorelin [24]. In particular, there were significant improvements in tasks involving executive functions and, to a slightly lesser extent, verbal memory. Importantly, these cognitive benefits were consistent across both groups, those with MCI and cognitively healthy participants, highlighting the broad potential of tesamorelin in supporting brain function. In addition to the cognitive benefits, participants treated with tesamorelin also experienced physiological improvements. Their levels of insulin-like growth factor-1 (IGF-1), an important hormone associated with cell growth and healthy ageing, increased by approximately 117%, yet remained within safe physiological ranges [24]. In addition, participants receiving tesamorelin showed a significant reduction in body fat, by an average of 7.4%. Interestingly, fasting insulin levels increased slightly (by about 35%) in MCI subjects, but still remained within normal limits, indicating that glucose control was not severely adversely affected. In terms of safety, mild adverse reactions were reported more frequently by those taking tesamorelin (68%) compared with the placebo group (36%). However, there were no serious adverse effects directly related to tesamorelin treatment [24]. Baker et al. found that daily injections of this GHRH analogue over a 20-week period provided significant cognitive improvements and beneficial physiological changes in older adults. Furthermore, in a complementary study by Friedman et al (2013), researchers examined the effects of tesamorelin on specific brain chemicals (neurotransmitters) associated with cognitive health [25]. The study involved 30 adults (17 with MCI and 13 cognitively healthy individuals) who also received daily injections of 1 mg tesamorelin or placebo for 20 weeks. The researchers measured neurotransmitter levels at three separate times (at the start of the study, week 10 and week 20) in three key brain areas: the dorsolateral frontal cortex (important for executive function), the posterior cingulate cortex (associated with memory and cognitive control) and the posterior parietal cortex (involved in spatial reasoning and attention). The results of this study provided interesting evidence of how tesamorelin affects the brain at a chemical level. Importantly, levels of gamma-aminobutyric acid (GABA), the main neurotransmitter responsible for calming excessive brain activity, increased significantly in all three brain regions measured [25]. This increase in GABA suggests enhanced inhibitory brain signalling, potentially helping the brain to function more smoothly and efficiently. Another neurotransmitter, N-acetylaspartylglutamate (NAAG), similarly increased in the dorsolateral frontal cortex. NAAG is also involved in stabilising brain signals, further supporting balanced brain activity. In addition, myo-inositol (MI) levels, a marker often elevated in conditions such as Alzheimer's disease and indicative of brain inflammation or stress, decreased significantly in the posterior cingulate region. This decrease in MI may reflect reduced cellular stress or inflammation in the brain [25]. It is noteworthy that levels of glutamate, a neurotransmitter involved in stimulating brain activity, did not change significantly, indicating that tesamorelin specifically enhances inhibitory rather than excitatory signals. Friedman et al. concluded that these findings provide the first strong evidence that tesamorelin therapy can positively modulate brain chemistry, potentially explaining the cognitive benefits observed in earlier studies [25]. These exciting results suggest that long-term tesamorelin therapy may become a valuable approach in promoting healthy cognitive ageing and potentially delaying or alleviating cognitive decline associated with ageing and MCI.

Tesamorelin reduces waist size in HIV patients

In another study, Ellis et al (2025) conducted a six-month, open-label trial involving 73 HIV patients with abdominal obesity and cognitive impairment [26]. They compared daily use of tesamorelin (2 mg) with standard care. The researchers found that tesamorelin significantly reduced waist circumference by approximately 2.7 cm compared to standard care. However, cognitive function improved only slightly in the tesamorelin group, and these changes were not statistically significant or better than standard care. Tesamorelin increased IGF-1 levels, but this did not correlate with improvements in cognitive function. The study authors concluded that tesamorelin is effective in reducing waist circumference in people living with HIV, but its effect on cognitive function remains uncertain and requires larger, long-term studies to better assess its potential role in improving brain health.

Pharmacokinetics of tesamorelin: how it behaves in the body

Tesamorelin is administered by subcutaneous injection and enters the bloodstream in small amounts after injection. The absolute bioavailability of tesamorelin is less than 4%, meaning that only a small proportion of the injected dose is actually absorbed and available to produce an effect [3, 27]. Despite this low absorption, the drug remains effective because it is designed to act rapidly and target specific hormonal pathways. Once it enters the bloodstream, tesamorelin is distributed throughout the body. The volume of distribution (which reflects how widely the drug spreads in the body) is about 9.4 litres per kilogram (L/kg) in healthy adults and slightly more, about 10.5 L/kg, in HIV-infected patients [3, 27]. This suggests that the drug has a relatively wide distribution, moving into tissues beyond the blood itself. Tesamorelin is rapidly cleared from the bloodstream, with a biological half-life of 26 minutes in healthy individuals and approximately 38 minutes in HIV-infected patients. This short half-life means that the drug does not remain in the body for too long, so it is usually taken once a day. Its plasma clearance, or elimination rate, is about 1060 litres per hour, indicating that the body processes and removes it quite rapidly [3, 27]. A study of population pharmacokinetics showed that age, body size, race and HIV status did not significantly affect how tesamorelin is absorbed or removed, meaning that the drug behaves similarly in different groups of people. Over the course of 14 days of repeated use, the body slightly adapted the way tesamorelin was absorbed, increasing the absorbed portion by approximately 13%, suggesting a slight adaptation without the need to change the dose [27]. In terms of metabolism, no formal human studies have determined exactly how tesamorelin is broken down in the body, but given its structure as a peptide, it is likely to be processed by enzymes that break down proteins into smaller components.

FDA approves Tesamorelin (Egrifta) for HIV-related lipodystrophy

On 10 November 2010. The US Food and Drug Administration (FDA) approved tesamorelin, marketed as Egrifta, as the first drug specifically indicated for the reduction of excess abdominal fat in HIV-infected adults with lipodystrophy [3]. Developed by Theratechnologies Inc. of Montreal, Canada, Egrifta is distributed in the US by EMD Serono.

Dosage of tesamorelin

The standard dosing regimen for tesamorelin is 2 mg injected subcutaneously once daily, usually in the abdominal region. Clinical trials have typically lasted between 6 and 12 months, and continued daily use is essential to maintain treatment benefit. According to Falutz et al (2008), discontinuation of therapy can lead to a reversal of the positive effect on abdominal fat reduction, indicating the importance of continuous adherence for sustained results.

Security and monitoring

Common adverse reactions observed in clinical trials include: injection site reactions (e.g. redness, itching), joint pain (arthralgia), pain in the extremities, peripheral oedema and myalgia. Tesamorelin may increase insulin-like growth factor 1 (IGF-1) levels and is associated with cases of glucose intolerance and hyperglycaemia. Regular monitoring of blood glucose and IGF-1 levels is therefore recommended. Consideration should be given to discontinuing the drug if patients develop persistent increases in IGF-1 levels or glucose intolerance.

Contraindications

Tesamorelin is contraindicated in pregnant women, people with known hypersensitivity to tesamorelin or mannitol, patients with active malignancies and people with disorders of the hypothalamic-pituitary axis, including those with hypophysectomy, hypopituitarism, pituitary tumours or surgery and radiation or head trauma.

What dose of tesamorelin should I take?

In virtually all controlled studies of tesamorelin - whether for hepatic steatosis (Fourman et al., 2020; Stanley et al., 2019) or HIV-related abdominal obesity (Falutz et al., 2010; Stanley et al., 2014) - the dose was 2 mg once daily, administered by subcutaneous injection.

How long does tesamorelin last?

In clinical trials, tesamorelin has shown consistent benefits in reducing both visceral and hepatic fat in people living with HIV. After 26 weeks (6 months) of daily treatment at a dose of 2 mg, HIV-infected adults experienced an average 11% reduction in visceral adipose tissue (VAT), as reported by Falutz et al (2010). During the same period, a separate study by Stanley et al. (2014) documented an average 2.0% decrease in liver fat. More pronounced effects were observed with longer use. According to Fourman et al (2020) and Stanley et al (2019), a relative reduction in liver fat of 37% was observed after 12 months in people with HIV and non-alcoholic fatty liver disease (NAFLD), as well as signs of slowed progression of fibrosis. Based on these results, a daily dose of 2 mg tesamorelin became the standard protocol. Measurable reductions in harmful fat deposits are typically seen after six months, while long-term use (up to 12 months) not only increases these reductions, but also results in beneficial changes in gene expression that may help protect against further liver damage and metabolic complications.

Does tesamorelin need to be stored in the fridge?

Tesamorelin in dry form can be stored at room temperature away from light. When dissolved with bacteriostatic water, it should be stored in the refrigerator.

How to take tesamorelin?

• Reconstitution: Add the diluent provided (bacteriostatic water) to 10 mg of lyophilised powder (3ml per 10ml), swirl gently to mix -. not shake.
• Dose collection: Take the prescribed volume ( for a 2 mg dose) into a syringe.
• Injection: Clean the selected area on the abdomen, pinch the skin, insert the needle at a right angle and inject slowly until all the drug has been administered.
• Disposal: Immediately dispose of needles and syringes in a suitable container

Where to inject tesamorelin?

Tesamorelin is administered by subcutaneous injection in the abdominal region:

• Choose a site around the navel, on the left or right side, avoiding scars, bruises or irritated skin.
• Change injection sites daily to minimise local reactions.
• Inject at an arrow-like angle under the surface of the skin, then dispose of sharp instruments as directed.

Can tesamorelin and ipamorelin be taken together?

While no randomised clinical trials have formally evaluated the combined use of tesamorelin (a GHRH analogue) and ipamorelin (a ghrelin-mimetic GH secretagogue), many peptide therapy clinics offer them in tandem to take advantage of complementary mechanisms - tesamorelin acting through GHRH receptors and ipamorelin through ghrelin receptors. Anecdotal reports suggest potential synergistic benefits in visceral fat reduction and muscle mass gain, but due to complex endocrine interactions and a lack of robust safety data, any combined regimen should only be pursued under close medical supervision. Tesamorelin and ipamorelin are peptides used to support fat loss, muscle health and anti-ageing, but they work through different biological pathways and have well-defined clinical profiles. Tesamorelin is an FDA-approved drug specifically designed to mimic growth hormone-releasing hormone (GHRH). It works by stimulating the pituitary gland to release more natural growth hormone (GH), which increases levels of IGF-1, a key hormone that promotes fat burning, muscle repair and metabolism. Tesamorelin is best known for its ability to target deep abdominal (visceral) fat, particularly in people with HIV-related lipodystrophy, and has also shown benefits in reducing liver fat, improving mitochondrial function and improving body composition. On the other hand, ipamorelin is a growth hormone stimulant that works by mimicking the hunger hormone ghrelin. It activates a different receptor than tesamorelin to stimulate GH release, without significantly affecting cortisol or prolactin levels, making it one of the milder, more selective GH-releasing peptides (GHRPs). Ipamorelin is often used in anti-ageing clinics and wellness programmes for those looking to improve sleep, recovery, skin quality and mild fat loss. Although it also raises GH levels, it has a milder and more balanced effect compared to more potent peptides or full GHRH analogues such as tesamorelin. When comparing the two, tesamorelin is more potent and targeted, particularly for clinical issues such as visceral fat and non-alcoholic fatty liver disease (NAFLD). It is supported by numerous human studies and is legally available by prescription. Ipamorelin is more commonly used off-label, often in combination with other peptides (such as CJC-1295 or sermorelin) for a broader growth hormone response. Although ipamorelin is popular for general wellbeing and anti-ageing, it does not have the same level of evidence or regulatory approval as tesamorelin.

Does tesamorelin increase testosterone levels?

Clinical studies have shown no direct effect of tesamorelin on serum testosterone levels. In phase 3 studies stratified according to baseline testosterone use, there were no significant changes in endogenous testosterone; the main hormonal effects of tesamorelin relate to GH and IGF-1 with no significant change in gonadal steroidogenesis

Use of Tesamorelin with TRT (testosterone replacement therapy)

Although tesamorelin and testosterone replacement therapy (TRT) work differently, they can have complementary effects when used together. Tesamorelin is a synthetic form of growth hormone-releasing hormone (GHRH), which stimulates the body to naturally produce more growth hormone, which in turn increases levels of IGF-1, a hormone important for fat metabolism, muscle growth and cell repair. On the other hand, TRT restores testosterone levels in men with low T, helping with energy, libido, strength, mood and fat distribution. Combining tesamorelin with TRT is a strategy used by some men to optimise hormonal balance, body composition and overall vitality. Combining tesamorelin with TRT has the potential to enhance the benefits of both therapies. For example, while TRT helps build lean muscle mass and improve strength, tesamorelin specifically targets visceral fat (harmful fat around the organs), which TRT alone may not reduce effectively. Studies have also shown that tesamorelin improves liver health, reduces inflammation and supports mitochondrial function, making it a useful supplement for those with metabolic problems or non-alcoholic fatty liver disease (NAFLD). Meanwhile, TRT enhances androgenic effects such as sexual function, mood stabilisation and bone density - areas where tesamorelin has limited effect. From a safety perspective, the use of both is generally considered to be well tolerated if properly monitored. Neither tesamorelin nor TRT has been shown to worsen insulin sensitivity or blood sugar control when dosed appropriately. However, both therapies may raise IGF-1 and red blood cell levels (TRT in particular raises haematocrit), so it is important to consult a doctor who can regularly monitor blood tests. Unmonitored use may increase risks, such as elevated IGF-1 levels, thickened blood or hormonal imbalance.

AOD9604 vs Tesamorelin

Tesamorelin and AOD9604 are used to reduce body fat, but work in different ways. Tesamorelin is a drug that helps the body produce more natural growth hormone. This stimulates a number of effects that help burn deep belly fat and improve liver health, particularly in people with HIV-related fat accumulation. In contrast, AOD9604 is a small part of the growth hormone molecule, specifically designed to focus only on burning fat without affecting growth or hormone levels such as IGF-1. This makes AOD9604 attractive to people who want to lose fat without the side effects of full growth hormone therapy. Tesamorelin has solid research behind it and is already FDA-approved, used mainly in HIV patients with excess abdominal fat (a condition called lipoarthropathy). Studies have shown that it can reduce deep abdominal fat by 11-18%, reduce liver fat by up to 37% and even slow liver scarring. It also improves muscle size and strength, increases energy at the cellular level and may improve brain function in older people. AOD9604 has shown similar benefits in early animal studies and short-term human studies, particularly in burning fat and supporting bone health, but has not been tested in such depth in humans. AOD9604 has also been tested for joint and cartilage protection, helping with conditions such as arthritis. In terms of safety, both compounds are well tolerated, but there are key differences between them. Tesamorelin slightly raises levels of IGF-1, a natural hormone associated with growth, but in studies it did not cause problems with blood sugar or insulin levels. AOD9604 is specifically designed not to raise IGF-1 or affect blood sugar levels, making it arguably safer for people at risk of diabetes. Studies have shown that AOD9604 did not cause serious side effects, even at higher doses. It does not accumulate in the body or damage DNA. Most of the side effects reported for both compounds are mild, such as redness at the injection site or mild headaches. Furthermore, Tesamorelin is now a prescription drug available as a daily injection under the name of Egrifta SV®, while AOD9604 is still considered experimental and is not approved by the FDA. It is only available for research or in some wellness clinics. Tesamorelin can be legally used by prescription, but AOD9604 is banned by sports organisations such as WADA because it is still in development.

Disclaimer

This article has been written for educational purposes and is intended to raise awareness of the substance under discussion. It is important to note that the article is about the substance in general - it is not a description of a specific product (chemical reagent). We are not suggesting the use of chemical reagents on humans - this is prohibited by law, for a product to be used for treatment it must be registered as a medicine. The information contained in the text is based on available scientific research and is not intended as medical advice or to promote self-medication. The reader should consult with a qualified health professional for all health and treatment decisions.      

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