Tesamorelin

A laboratory copy of the hormone the brain uses to tell the pituitary gland to release growth hormone. The chain itself is the 44-amino-acid human growth hormone releasing factor, GRF(1-44), which can be read directly in the UniProt entry P01286 for the human hormone. What makes it a medicine rather than the plain hormone is a small fatty chain — a six-carbon trans-3-hexenoyl group — bolted onto the tyrosine at the start of the chain, which is why published papers call it a stabilised analogue. The sequence field is left empty for that reason: the bare one-letter code would describe unmodified GRF, a molecule that behaves differently, and the register does not print a string that names the wrong thing. Sold in the United States as Egrifta, then Egrifta SV, and since 25 March 2025 as Egrifta WR.

Sold as

Injection under the skin of the belly, once a day.

Legal status in the EU

Not an approved medicine in the EU. The application was submitted to the European Medicines Agency on 31 May 2011 and withdrawn on 21 June 2012 while under review; the agency's medicine page still records the status as "application withdrawn", and it has never been resubmitted. It is an approved prescription medicine in the United States, where it has been on sale since November 2010 and where the current product is Egrifta WR. It is prohibited in sport at all times, in and out of competition, and named by name in section S2.2.4 of the WADA 2026 Prohibited List among GHRH analogues alongside CJC-1293, CJC-1295 and sermorelin.

It grips the same receptors on the pituitary gland as the body's own releasing hormone, with about the same strength in a laboratory dish, and the gland puts out more growth hormone — still in natural bursts, not a flat stream. Growth hormone then makes the liver release IGF-1, the growth signal that reaches muscle, bone and fat, and it also drives fat breakdown, with the deep fat behind the abdominal wall the most responsive store. The compound itself does not linger: half of an injected dose has left the blood in about 8 minutes, and under 4 per cent of what is injected reaches the bloodstream at all, which is why it is injected daily.

Part of the bodyWhat happensHow it is knownKind of evidence

Fat deep inside the belly, around the organs

This is the one thing it is approved for. The fat it moves is not the layer you can pinch — it is the fat packed in behind the muscle wall, around the liver and the gut. In the first big trial that fat fell by 15.2 per cent over 26 weeks while it grew by 5.0 per cent in people on a dummy injection. In the second it fell by 10.9 per cent against 0.6 per cent. The fat under the skin of the belly and the fat on the arms and legs did not change. If the injections stop, the fat comes back: people switched to a dummy injection for the second half of a year regained most of what they had lost.

Measured by CT scan in two randomised trials with dummy-injection groups, 412 and 404 adults with HIV, 26 weeks each, with a further 26 weeks in which some people were switched to a dummy injection without knowing.

Measured in people

Source [03]Source [04]Source [12]

The growth signal in the blood (IGF-1)

Growth hormone makes the liver release IGF-1, and IGF-1 is what actually reaches muscle, bone and fat. It goes up a great deal. In the first trial it rose by 81 per cent while falling 5 per cent on the dummy injection. It rises far enough to leave the normal range for many people: after 26 weeks, 47 per cent of people treated were above the normal band by more than two standard deviations and 36 per cent by more than three, an effect already visible at 13 weeks. The product information tells doctors to measure IGF-1 during treatment and to consider stopping if it stays that high. What prolonged high IGF-1 does to a person is stated in the label itself as unknown.

Measured in blood in both randomised trials, 816 adults in total, and reported in the approved US product information for the 26-week and 52-week points.

Measured in people

Source [02]Source [03]

The liver

Fat inside liver cells falls. In a 12-month trial in people with HIV whose livers already held too much fat, the fat fraction dropped by about a third more than on a dummy injection, and 35 per cent of people treated ended below the 5 per cent threshold that defines a fatty liver, against 4 per cent of those on the dummy injection. A smaller six-month trial found the same direction. What is not known is whether this changes the scarring that makes a fatty liver dangerous: the trial took liver samples, but it was designed to measure fat, and its own authors wrote that further studies are needed for the tissue question.

Measured by magnetic resonance in a randomised trial with a dummy-injection group, 61 adults with HIV and fatty liver disease, 12 months, and in an earlier randomised trial of 50 adults over 6 months.

Measured in people

Source [14]Source [15]

Blood sugar

Growth hormone works against insulin, and this shows. Over the first 26 weeks, 5 per cent of people treated crossed the line into diabetes as measured by a long-term blood sugar test, against 1 per cent on the dummy injection — a rate a little over three times higher. Average blood sugar did not shift much and most people's numbers stayed where they were, but the label tells doctors to check blood sugar before starting and to keep checking. A separate 12-week trial in 53 people who already had type 2 diabetes found no worsening of their control at either amount tested, and that trial was paid for by the manufacturer.

Measured in 543 treated adults and 263 on a dummy injection over the first 26 weeks of the two randomised trials, and separately in a 12-week randomised trial of 53 people with type 2 diabetes.

Measured in people

Source [02]Source [16]

Joints, hands and swelling

The body holds on to more fluid, and that is what most people actually feel. Joint pain, aching muscles, swollen ankles, pins and needles, numb patches and carpal tunnel syndrome — a pinched nerve at the wrist that makes the hand tingle and weaken — all turned up more often on tesamorelin than on the dummy injection. The label describes these as either passing or clearing up when treatment stops.

Counted in 543 adults given tesamorelin and 263 given a dummy injection over the first 26 weeks of the two randomised trials.

Measured in people

Source [02]

The immune system

About half the people who take it make antibodies against it. That figure was 50 per cent at 26 weeks and 47 per cent at 52. Among the people who had an allergic-type reaction, 85 per cent had them. Roughly 60 per cent of the people who made antibodies made ones that also stuck to the body's own growth hormone releasing hormone. In the trials this did not blunt the effect: the fat reduction and the IGF-1 rise were the same in people with and without antibodies, and at 52 weeks only 10 per cent had antibodies that blocked the drug in a test tube. Six months after stopping, 18 per cent of those who had them still did.

Measured by blood test in the two randomised trials at 26 and 52 weeks, and reported in the approved US product information.

Measured in people

Source [02]

Body weight and the fat you can pinch

Nothing happens. This is the most misunderstood fact about the compound, and the label states it flatly: it is not a weight-loss medicine, because it is weight-neutral. Over 26 weeks the difference in body weight between tesamorelin and a dummy injection was four hundred grams in one trial and two hundred grams the other way in the other, and neither was a real difference. Waist measurement fell by 2 centimetres more than on the dummy injection in one trial and 1 centimetre in the other. Fat under the skin of the belly, and fat on the arms and legs, did not move.

Measured in 816 adults across the two randomised trials with dummy-injection groups, 26 weeks.

Measured in people

Source [02]Source [04]

Thinking and memory

Two trials looked and disagreed. In 152 adults aged 55 to 87 — 66 of them with mild memory trouble — 20 weeks of a smaller nightly injection produced a measurable improvement in thinking, driven mostly by tests of planning and mental flexibility. In 73 people with HIV and a large waist, six months of the full daily amount produced no difference from usual care at all. The second trial was open — everyone knew who was getting what — had no dummy injection, and its authors said plainly that it was too small to settle the question.

One randomised trial with a dummy-injection group, 152 older adults, 20 weeks; one open randomised trial against usual care with no dummy injection, 73 adults with HIV, 6 months.

Studies in people disagree

Source [18]Source [19]

The pituitary gland, at the base of the brain

Tesamorelin latches onto the gland that makes growth hormone — a pea-sized gland under the brain — and tells it to release more. In a laboratory dish it grips that gland's receptors about as strongly as the body's own hormone does. The natural rhythm is kept: growth hormone still comes out in bursts, and in 13 healthy men two weeks of daily injections made both the bursts and the background level bigger rather than flattening them. The compound itself is gone almost at once. Half of an injected dose has cleared the blood in about 8 minutes, and less than 4 per cent of what is injected ever reaches the bloodstream at all.

Receptor binding measured in a laboratory dish; the burst measurements come from 13 healthy men aged around 45 who had blood taken through the night before and after two weeks of daily injections. The clearance figures are from the approved product information.

One small study

Source [02]Source [13]

Muscle

There is something here, and it is smaller and shakier than the way tesamorelin is sold online would suggest. Lean body mass — muscle, organs and water together, not muscle alone — rose by about 1.2 to 1.3 kilograms over 26 weeks against roughly no change on the dummy injection. A later re-analysis of the scans from the same two trials found the trunk muscles were slightly bigger and denser, by fractions of a square centimetre. But that re-analysis compared only the people whose deep belly fat had actually fallen by 8 per cent or more against everybody on the dummy injection, which is no longer a fair coin toss. No published study has tested anyone's strength, or measured what happens to a limb muscle in someone who lifts weights.

Lean body mass measured in both randomised trials at 26 weeks. The muscle size and density figures come from an exploratory re-analysis of CT scans from those trials, 193 responders against 148 people on a dummy injection.

One small study

Source [02]Source [17]

Two randomised, dummy-controlled trials of 412 and 404 adults with HIV measured the same thing over 26 weeks: the deep fat inside the belly fell 15.2 per cent while rising 5.0 per cent on the dummy injection in the first, and fell 10.9 per cent against a fall of 0.6 per cent in the second. Body weight did not change in either, and the fat under the skin did not change. The US regulator approved it on 10 November 2010 on that basis. Europe's regulator, given the same data, reached the opposite conclusion: Ferrer Internacional withdrew the EU application on 21 June 2012 after the CHMP formed a provisional opinion against it, on the grounds that lipodystrophy fat could not be told apart from ordinary obesity in practice, that the fat reduction had not been shown to be clinically meaningful, that the IGF-1 rise was a major safety concern, and that no long-term safety data had been supplied. Two studies designed after approval to settle the open questions — a ten-year cohort of 391 people measuring new cancers, and a randomised trial of 129 people measuring diabetic eye disease — were both terminated in August 2018 with no results posted. The sequence field is null on purpose: the 44-residue chain is human GRF(1-44), verified letter by letter against UniProt P01286, but the molecule carries a trans-3-hexenoyl group on its first residue, so the plain code would describe a different substance.

The compound itself is gone within minutes — half of a dose has left the blood in about 8 minutes — but what it sets off lasts much longer. IGF-1 is already far above where it started by week 13. Deep belly fat falls steadily through the first 26 weeks and then stops falling: a second 26 weeks of treatment held the loss rather than adding to it. Liver fat was measured at 12 months. Nothing is permanent. People switched to a dummy injection at week 26 had regained 16 to 22 per cent of the fat by week 52, and the label's own account is that the effects do not outlast the treatment. Nobody in a controlled study has been followed for longer than a year.

What was measuredWhat happenedIn whomHow it is known

Fat deep inside the belly, around the organs

Fell 15.2 per cent while rising 5.0 per cent on a dummy injection, over 26 weeks. In the measurements the regulator used, that is a fall of 27 square centimetres against a rise of 4, a difference of 31 square centimetres (95 per cent confidence interval 24 to 39).

412 adults with HIV and excess belly fat, 86 per cent of them men, average age 48; 273 received tesamorelin and 137 a dummy injection. Neither they nor the staff knew which.

Measured in people

Source [02]Source [03]

Fat deep inside the belly, in the second trial

Fell 10.9 per cent — 21 square centimetres — against 0.6 per cent, or 1 square centimetre, on a dummy injection, over 26 weeks. Smaller than the first trial, in the same direction.

404 adults with HIV and excess belly fat, run between January 2007 and October 2008; 270 received tesamorelin and 126 a dummy injection.

Measured in people

Source [02]Source [04]

What happens when you stop

The fat comes back. People kept on tesamorelin for a second 26 weeks held roughly steady — no further loss, but no regain. People secretly switched to a dummy injection at week 26 regained 22 per cent in one trial and 16 per cent in the other. Over a full year of continuous treatment the total reduction settled at about 18 per cent below where people started.

207 and 177 adults who had completed 26 weeks on tesamorelin, re-randomised without being told to either continue or switch to a dummy injection for a further 26 weeks.

Measured in people

Source [02]Source [12]

Body weight

No difference. Weight fell 0.4 kilograms on tesamorelin and did not move on the dummy injection in the first trial; in the second it rose 0.5 kilograms against 0.3. Neither gap was real. The approved label states in its own limitations that the medicine is weight-neutral and is not indicated for weight loss.

816 adults with HIV across both randomised trials, 26 weeks.

Measured in people

Source [02]

IGF-1, the growth signal growth hormone works through

Rose 81 per cent while falling 5 per cent on a dummy injection. In the regulator's figures that is a rise of 107 to 108 nanograms per millilitre against a change of −15 to +3, from starting levels around 150 to 160. After 26 weeks, 47 per cent of people treated were more than two standard deviations above the normal band for their age and sex, and 36 per cent were more than three.

816 adults with HIV across both randomised trials, 26 weeks; the standard-deviation figures cover everyone treated, with 52-week figures from those who continued.

Measured in people

Source [02]Source [03]

Blood fats

Triglycerides fell by 50 milligrams per decilitre while rising by 9 on the dummy injection, and the ratio of total to good cholesterol fell 0.31 while rising 0.21. Both differences were solid. Over 52 weeks the triglyceride improvement held, while good cholesterol slipped slightly.

412 adults with HIV in the first randomised trial over 26 weeks, followed to 52 weeks in the extension.

Measured in people

Source [03]Source [12]

Fat inside the liver

Fell about 37 per cent further than on a dummy injection over 12 months — in absolute terms 4.1 percentage points of the liver's weight (95 per cent confidence interval 0.7 to 7.6). After a year, 35 per cent of people treated no longer met the definition of a fatty liver, against 4 per cent of those on the dummy injection.

61 adults with HIV whose livers held at least 5 per cent fat, split one to one between tesamorelin and a dummy injection for 12 months. Neither they nor the staff knew which.

Measured in people

Source [14]Source [20]

Developing diabetes

5 per cent of people on tesamorelin crossed into the diabetic range on a long-term blood sugar test in the first 26 weeks, against 1 per cent on a dummy injection. The risk over time was 3.3 times higher (95 per cent confidence interval 1.4 to 9.6). Everyone started at the same average level.

543 adults given tesamorelin and 263 given a dummy injection across the two randomised trials, first 26 weeks. People who already had diabetes had been excluded from those trials.

Measured in people

Source [02]

Lean body mass

Rose 1.3 kilograms in the first trial and 1.2 in the second, against a fall of 0.2 kilograms and essentially no change on the dummy injection. Lean body mass is everything that is not fat — muscle, organs, bone and body water together — so this is not a measurement of muscle.

816 adults with HIV across both randomised trials, 26 weeks.

Measured in people

Source [02]

Thinking and memory

The two trials point different ways. In 152 older adults, 20 weeks of a nightly 1 milligram injection improved overall cognition against a dummy injection, with the clearest gain in planning and mental flexibility and a hint of one in verbal memory. In 73 people with HIV, six months of the full 2 milligram daily amount produced no difference against usual care — both groups drifted upward and the gap between them was nowhere near significant.

152 adults aged 55 to 87, of whom 66 had mild memory trouble, over 20 weeks with a dummy injection. And 73 adults with HIV and a large waist over 6 months, open-label against usual care with no dummy injection.

Studies in people disagree

Source [18]Source [19]

Size and density of the trunk muscles

Slightly bigger and slightly denser: the rectus and psoas muscles gained about half a square centimetre of cross-section, and all four trunk muscle groups gained 1.6 to 4.9 units of density on the scanner's scale. The comparison is not a fair one, because the tesamorelin side included only the people whose deep belly fat had already fallen by 8 per cent or more.

193 people who responded to tesamorelin against 148 people on a dummy injection, from scans taken in the two randomised trials at 26 weeks. 87 per cent men.

One small study

Source [17]

New cancers, and diabetic eye disease

Never reported. Two studies were set up to answer exactly these two questions after approval — a ten-year follow-up of 391 people whose main measure was time to a new cancer, and a randomised trial of 129 people with diabetes whose main measure was whether their eye disease got worse. Both were terminated in August 2018 and neither has posted a result. The registry gives no reason for either.

391 adults with HIV in the cancer cohort, 2013 to 2018; 129 adults with HIV and diabetes in the eye trial, 2012 to 2018.

Claimed, never tested

Source [10]Source [21]

Most of what people feel comes from the body holding on to fluid: joint pain (13 per cent against 11 on a dummy injection), swollen ankles and aching muscles (6 against 2), pins and needles (5 against 2), numb patches (4 against 2) and occasional carpal tunnel syndrome. Reactions where the needle goes in affected 1 in 4 people against about 1 in 7 on the dummy injection. Around 5 per cent developed diabetes within 26 weeks against 1 per cent on the dummy injection, a risk 3.3 times higher (95 per cent CI 1.4 to 9.6). IGF-1 rose above the normal band by more than two standard deviations in 47 per cent of people at 26 weeks. About half made antibodies against the drug, and in about 3 in 5 of the people who did, those antibodies also stuck to the body's own releasing hormone. It is forbidden in active cancer, in pregnancy, in anyone whose pituitary control has been disrupted, and in anyone allergic to it. No lifetime cancer study in animals has ever been done, and the human study set up to answer the cancer question was terminated without a result.

EffectWhat it feels likeHow often

Developing diabetesSerious

Growth hormone works against insulin, so a medicine that raises growth hormone can push blood sugar up. The label tells doctors to check blood sugar before starting and periodically after, and to consider stopping in anyone who develops diabetes without a clear benefit from treatment. It also says to watch the eyes of people who already have diabetes, because raised IGF-1 may worsen the eye damage diabetes causes. The trial that was set up to test that eye question was terminated without posting a result.

5 in 100 people over the first 26 weeks, against 1 in 100 on a dummy injection.

Source [02]Source [21]

Reactions where the needle goes in

Redness, itching, pain, irritation, swelling, hives and bruising at the injection site. It is the single commonest complaint on the medicine, and the label tells people to move the injection around the belly and to avoid scars, bruises and the navel. The injection is a daily one, indefinitely, which is why this matters more than the numbers suggest.

1 in 4 people, against about 1 in 7 on a dummy injection. Counted more narrowly, 17 per cent against 6 per cent.

Source [02]

Joint pain

The gap is small but it belongs to a cluster the label groups together as fluid retention: aching joints, aching muscles, swollen ankles and a pinched nerve at the wrist. The label describes them as passing, or as clearing up when the injections stop.

13 in 100 people, against 11 in 100 on a dummy injection.

Source [02]

Swollen ankles and legs, and aching muscles

Fluid gathering in the tissues. Carpal tunnel syndrome — the pinched wrist nerve that makes a hand tingle and weaken — turned up in about 1 in 100 people on tesamorelin and in nobody on the dummy injection.

6 in 100 people each, against 2 in 100 on a dummy injection.

Source [02]

Pins and needles, and numb patches

Part of the same fluid-retention picture: tissue swelling presses on nerves. It is reported as a nuisance rather than a lasting problem in the trials, though nobody was followed beyond a year.

5 in 100 and 4 in 100 people respectively, against 2 in 100 on a dummy injection for each.

Source [02]

Allergic-type reactions

Itching, redness, flushing, hives and rash. The label tells anyone who suspects one to stop the injections and get medical help at once. Among the people who had one, 85 per cent had made antibodies against the drug.

4 in 100 people in the trials.

Source [02]

Antibodies against the drug, and against your own hormone

In the trials this did not stop the drug working: fat reduction and IGF-1 response were the same with or without antibodies, and only 10 per cent of people had antibodies that blocked it in a laboratory test at 52 weeks. What it means to carry antibodies that cross-react with your own hormone for years is not something these trials could answer — the longest ran 52 weeks, and 18 per cent of people were still antibody-positive six months after stopping.

About 1 in 2 people at 26 weeks, and roughly 3 in 5 of them made antibodies that also stuck to the body's own growth hormone releasing hormone.

Source [02]

Anything to do with cancer

The medicine raises growth hormone and IGF-1, both of which are growth signals, and the label bans its use in anyone with an active cancer for that reason. It also tells doctors to weigh the higher background cancer risk that comes with HIV before starting, and to stop at any sign of a cancer returning. Tesamorelin did not damage DNA in the standard laboratory tests. That is not the same as knowing what years of raised IGF-1 do.

Not measured. No lifetime cancer study in animals has ever been done with tesamorelin, and the ten-year human follow-up designed to answer the question was terminated with no result posted.

Source [02]Source [10]

Anything that takes longer than a year to appear

The medicine is meant to be taken indefinitely — stop and the fat returns — but nobody has been followed in a controlled study for longer than a year. The European regulator listed the absence of long-term safety data as one of its reasons for not approving it. The label also warns that giving growth hormone to people who are critically ill has increased deaths, and tells doctors to consider stopping tesamorelin in anyone in that state.

Not measured. The longest randomised treatment period is 52 weeks, and the 12-month liver trial.

Source [02]Source [05]

These are the amounts the studies below gave their participants, and they are here as facts about those studies. They are not a recommendation, not a starting point and not a range to pick from. What a person should take, if anything, is a question for a doctor who knows them.

The two trials the approval rests on — Falutz and colleagues 2007 and 2010, deep belly fat in adults with HIV and lipodystrophy, against a dummy injection

2 mg injected under the skin once a day.

26 weeks, followed by a further 26 weeks in which people were secretly re-assigned to continue or to switch to a dummy injection.

Source [03]Source [04]Source [22]

The approved products themselves. The amount on the label is not the amount used in the trials, because later formulations deliver the same exposure from a smaller injection

EGRIFTA SV: 1.4 mg once a day. EGRIFTA WR, approved 25 March 2025 and now replacing it: 1.28 mg once a day. Both under the skin of the belly.

Indefinitely, for as long as a doctor judges the benefit worth it. The label tells doctors to weigh continuing in anyone whose deep belly fat has not fallen.

Source [01]Source [02]

Stanley and colleagues 2019 — fat inside the liver, in adults with HIV and fatty liver disease, against a dummy injection

2 mg injected under the skin once a day.

12 months, followed by 6 months in which everyone received tesamorelin and knew it.

Source [14]Source [20]

Baker and colleagues 2012 — thinking and memory in older adults with and without mild memory trouble, against a dummy injection

1 mg injected under the skin by the participant, 30 minutes before bedtime, once a day. Half the amount used in the HIV trials.

20 weeks, with a further 10 weeks of measurement after stopping.

Source [18]Source [23]

Clemmons and colleagues 2017 — whether it upsets blood sugar control in people who already have type 2 diabetes, against a dummy injection. Paid for by the manufacturer

1 mg or 2 mg injected under the skin once a day, in separate groups, against a dummy injection.

12 weeks.

Source [16]

What people report

• Whether shrinking the deep belly fat makes anyone healthier — no trial has measured heart attacks, strokes or deaths, and the European regulator gave this as a reason for not approving it.
• Whether it raises the risk of cancer: the ten-year follow-up study set up to answer that, in 391 people, was terminated in 2018 with no result posted, and no lifetime cancer study in animals has ever been done.
• Whether it makes diabetic eye disease worse: the randomised trial of 129 people set up to answer that was also terminated in 2018 with no result posted.
• What happens after a year. No controlled study has run longer, and the medicine is meant to be taken indefinitely.
• Whether it adds any strength — never measured, in any study.
• Whether it does anything for anyone without HIV who simply has a large waist: every trial of the deep belly fat was run in people with HIV.
• Whether it helps a fatty liver in someone who does not have HIV: both trials that measured liver fat were run in people with HIV.
• Whether it changes liver scarring, as opposed to liver fat.
• Whether it improves thinking. One trial in 152 older adults said yes and one in 73 people with HIV said no, and neither was big enough to settle it.
• What carrying antibodies against your own growth hormone releasing hormone for years does — about 3 in 5 people who make antibodies make that kind, and nobody has been followed past 52 weeks.
• What it does in children — never studied, at any amount.
• What it does in people with kidney or liver problems, or in older people — the label states the drug's behaviour in all three has not been established.
• How it behaves in people who already have diabetes over more than 12 weeks: the phase 3 trials excluded them, and the one trial that included them was short and paid for by the manufacturer.
• Whether women respond differently: 84 to 86 per cent of the people in the two main trials were men, and no result has been reported separately for women.
• What is in vials sold online as tesamorelin, which is a different question from what is in the licensed product.
• Whether it interacts with anything beyond the two medicines tested — only simvastatin and ritonavir have been formally checked.

Does tesamorelin work?

For the one thing it is approved for, yes, and the effect has been measured properly. In two trials of about 400 people each, the deep fat inside the belly fell by around 15 per cent and 11 per cent over six months, while it rose or stayed flat in people injecting a dummy. It does not make you lighter and it does not touch the fat you can pinch. Europe's regulator accepted that the fat shrank but was not persuaded this made people healthier, which is why the medicine is approved in the United States and not in the EU.

Source [03]Source [05]

Is tesamorelin legal?

It depends where you are and how you got it. In the United States it is a prescription medicine, sold as EGRIFTA WR, approved only for reducing excess belly fat in adults with HIV who have lipodystrophy. In the European Union it is not an approved medicine at all — the application was withdrawn in June 2012 and never resubmitted — so nothing sold as tesamorelin in Europe is a licensed product. Buying it as a research chemical online is a different thing again from being prescribed it, and in sport it is banned outright.

Source [01]Source [06]Source [07]

What are the side effects of tesamorelin?

The common ones are joint pain, reactions where the needle goes in, swollen ankles, aching muscles, pins and needles and numb patches — most of them caused by the body holding on to extra fluid. About 1 in 20 people developed diabetes during the first six months of the trials, against 1 in 100 on a dummy injection. About half the people taking it make antibodies against it, which in the trials did not stop it working. It must not be used by anyone with an active cancer or during pregnancy.

Source [02]

Tesamorelin vs CJC-1295 — what is the difference?

Both copy the same brain hormone, and that is where the similarity ends. Tesamorelin is an approved medicine: it went through two randomised trials of about 400 people each, has a public label anyone can read, and clears the blood within minutes, so it is injected every day. CJC-1295 was abandoned by its developer after a participant died in its only trial in patients, has never been approved anywhere, and in its long-acting form stays in the blood for over a week. Nothing about CJC-1295 has been measured in a person beyond hormone levels in blood — no muscle, no fat, no strength.

Source [02]Source [24]

Does tesamorelin build muscle?

Nobody has tested that properly. What the trials measured was lean body mass — muscle, organs, bone and body water lumped together — which rose by about 1.2 kilograms over six months, some of which is simply the extra fluid the medicine makes you hold. A later re-analysis of the same scans found the trunk muscles were slightly bigger and denser, but it compared only the people the drug had already worked for against everybody on the dummy injection, which is not a fair test. No published study has measured anyone's strength on it.

Source [02]Source [17]

Is tesamorelin a weight loss drug?

No, and its own label says so. Under limitations of use it states that the medicine is not indicated for weight loss management because it is weight-neutral. Across 816 people in the two trials, body weight moved by less than half a kilogram in either direction and no differently from a dummy injection. What it shifts is one specific fat store, the fat packed in behind the abdominal wall — and it shifts that only for as long as you keep injecting.

Source [02]Source [12]

Can you buy tesamorelin?

In the United States, with a prescription, as EGRIFTA WR. In the EU there is no licensed product to buy, because it was never approved there. Vials sold online as tesamorelin for research are outside all of that: nobody has checked what is in them, and a 2026 review in Sports Medicine describes exactly this parallel market in peptides sold direct to patients without regulatory oversight. This register does not link sellers and does not tell anyone how to use anything.

Source [06]Source [25]

Is tesamorelin banned in sport?

Yes, at all times, in and out of competition. The 2026 prohibited list names it by name under section S2.2.4, among growth hormone releasing hormone and its analogues, alongside CJC-1293, CJC-1295 and sermorelin. A laboratory method sensitive enough to find it in urine was published in 2021 — although that paper also notes that accredited anti-doping laboratories had not actually found these substances in samples up to then, despite evidence that athletes use them.

Source [07]Source [26]

Why was tesamorelin rejected in Europe?

It was not formally rejected — the company withdrew the application in June 2012 once it became clear the committee would not approve it. The published reasons were four: doctors would not be able to tell the belly fat of lipodystrophy apart from ordinary obesity; the threshold the company proposed for who should get it was not well enough supported; the fat reduction had not been shown to bring any actual health benefit; and the large rise in IGF-1 was called a major safety concern because high IGF-1 is linked to cancer risk and to worsening diabetic eye disease. The committee also noted that no long-term safety data had been provided for a medicine meant to be taken indefinitely.

Source [05]Source [27]

Does tesamorelin help with fatty liver?

In people with HIV, the fat in the liver did fall — by about a third more than on a dummy injection over a year, with 35 per cent of people treated dropping below the threshold for a fatty liver against 4 per cent on the dummy. That is one trial of 61 people. Whether it changes the scarring that makes a fatty liver dangerous is not settled; the trial's own authors said longer studies were needed. It is not approved for liver disease anywhere.

Source [14]

1. [01]EGRIFTA WR (tesamorelin for injection) US prescribing information, DailyMed — indication, dose 1.28 mg daily, contraindications, and the description of the 44-amino-acid GRF chain with its hexenoyl group (2025)
2. [02]EGRIFTA SV (tesamorelin for injection) US prescribing information — full clinical studies, adverse reaction and immunogenicity tables (2019)
3. [03]Falutz and colleagues, metabolic effects of a growth hormone-releasing factor in patients with HIV (N Engl J Med 2007;357:2359-70; 412 patients, VAT −15.2% vs +5.0%) (2007)
4. [04]Falutz and colleagues, effects of tesamorelin in HIV-infected patients with abdominal fat accumulation, with a safety extension (J Acquir Immune Defic Syndr 2010;53:311-22; 404 patients, VAT −10.9% vs −0.6%) (2010)
5. [05]Questions and answers on the withdrawal of the marketing authorisation application for Egrifta (tesamorelin), EMA/CHMP/475021/2012 (2012)
6. [06]Egrifta, European Medicines Agency medicine page — status: application withdrawn (2012)
7. [07]WADA World Anti-Doping Code International Standard, Prohibited List 2026 — section S2.2.4 names tesamorelin (2026)
8. [08]UniProt P01286 (SLIB_HUMAN, somatoliberin) — FASTA showing the 44-residue GRF chain YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL
9. [09]Drugs@FDA, BLA 022505 (Theratechnologies) — original approval recorded 10 November 2010 (2010)
10. [10]Ten-year prospective cohort safety study of subjects exposed to EGRIFTA, primary outcome time to malignancy (NCT01579695, 391 participants, TERMINATED, no results posted) (2018)
11. [11]EMA press release EMA/431454/2012, 26 June 2012 — Ferrer Internacional withdraws its marketing authorisation application for Egrifta; states that the application was submitted to the Agency on 31 May 2011 (2012)
12. [12]Falutz and colleagues, long-term safety and effects of tesamorelin over 52 weeks (AIDS) (2008)
13. [13]Stanley and colleagues, effects of a GHRH analog on endogenous GH pulsatility and insulin sensitivity in healthy men (J Clin Endocrinol Metab, free full text) (2011)
14. [14]Stanley and colleagues, effects of tesamorelin on non-alcoholic fatty liver disease in HIV, a randomised double-blind multicentre trial (Lancet HIV, free full text) (2019)
15. [15]Stanley and colleagues, effect of tesamorelin on visceral fat and liver fat, a randomized clinical trial (JAMA, free full text) (2014)
16. [16]Clemmons and colleagues, safety and metabolic effects of tesamorelin in patients with type 2 diabetes (PLoS One, free full text) (2017)
17. [17]Adrian and colleagues, tesamorelin decreases muscle fat and increases muscle area in adults with HIV (J Frailty Aging, free full text) (2019)
18. [18]Baker and colleagues, effects of growth hormone-releasing hormone on cognitive function in adults with mild cognitive impairment and healthy older adults (Arch Neurol, free full text) (2012)
19. [19]Ellis and colleagues, effects of tesamorelin on neurocognitive impairment in persons with HIV and abdominal obesity (Journal of Infectious Diseases) (2025)
20. [20]Tesamorelin Effects on Liver Fat and Histology in HIV (NCT02196831, completed, results posted) (2019)
21. [21]Trial of whether EGRIFTA increases development or progression of diabetic retinopathy (NCT01591902, terminated, no results posted) (2018)
22. [22]TH9507 in Patients With HIV-Associated Lipodystrophy (NCT00123253, 412 participants, completed, no results posted) (2007)
23. [23]SMART: Somatotrophics, Memory, and Aging Research Trial (NCT00257712, completed; the registry records 151 participants and the published paper 152) (2012)
24. [24]FDA briefing document for CJC-1295-related bulk drug substances, Pharmacy Compounding Advisory Committee, 4 December 2024 (2024)
25. [25]Mendias and Awan, safety and efficacy of approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance (Sports Medicine) (2026)
26. [26]Memdouh and colleagues, advances in the detection of growth hormone releasing hormone synthetic analogs (Drug Testing and Analysis) (2021)
27. [27]Ferrer Internacional withdraws its marketing authorisation application for Egrifta (tesamorelin), European Medicines Agency news (2012)