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Hunger is the main reason most diets fail. When calories drop, appetite climbs, cravings get louder and energy dips, and sooner or later most people eat their way back. Tesofensine is an experimental drug that works on that problem directly: it changes the brain chemistry that drives appetite.
It was first developed for Parkinson’s and Alzheimer’s disease, but patients in those trials lost weight, and it was then tested as an obesity treatment. In a 24-week trial published in The Lancet, it produced clearly more weight loss than placebo, mostly by making people less hungry.
This guide covers how tesofensine works, what the human trials found (and what comes only from animal studies), the doses used in studies, its effect on heart rate and blood pressure, and why it is still not an approved medicine.
Key Takeaways
- Tesofensine is an experimental oral drug that blocks the reuptake of serotonin, noradrenaline and dopamine. Its main effect is a lower appetite.
- In the 24-week Lancet trial, people taking 0.5 mg or 1.0 mg daily with a reduced-calorie diet lost roughly 9-11% more body weight than those on placebo.
- It is taken by mouth once a day, not injected. Studies used 0.25-1.0 mg; the 1.0 mg dose added little weight loss over 0.5 mg but caused more side effects.
- Blood pressure did not rise at 0.25 mg or 0.5 mg in that trial, but resting heart rate went up by about 7 beats per minute at 0.5 mg. Long-term heart safety is unknown.
- It is not approved by the FDA or in Europe. What is sold online is labelled for research use, and no regulator checks its purity or dose.
What Is Tesofensine?
Tesofensine (development code NS2330) is an experimental drug first developed by the Danish company NeuroSearch to treat Parkinson’s and Alzheimer’s disease. Those programmes did not continue, but researchers noticed that patients lost weight during the trials, which led to its development as an obesity treatment.
Tesofensine is a triple monoamine reuptake inhibitor. It slows the reabsorption of three brain chemicals, dopamine, noradrenaline (norepinephrine) and serotonin, so more of each stays active. These chemicals help regulate appetite, mood, alertness and energy use. Raising all three makes people feel less hungry and fuller on smaller meals, which makes a calorie deficit easier to keep.
It is a small-molecule drug taken by mouth, not a peptide and not an injection. In trials it was given as a once-daily oral dose, and online it is usually sold as capsules. For the full compound profile, see our tesofensine compound page.
How Tesofensine Suppresses Appetite
Most of what is known about how tesofensine works comes from animal studies, so it helps to keep the two kinds of evidence apart.
Animal Data
In diet-induced obese rats, tesofensine reduced food intake and body weight, and the effect depended on noradrenaline and dopamine receptor pathways. A rodent study also found that it quiets GABA-releasing neurons in the lateral hypothalamus, a brain area that drives feeding. When those neurons are less active, animals eat less.
Human Data
In people, the measured effect is on appetite: trial participants reported less hunger and more fullness and ate less. A smaller study of energy metabolism in overweight men found that the weight loss came mainly from eating less; any rise in calories burned was small. Tesofensine is best understood as an appetite suppressant, not a fat burner.
Because it raises noradrenaline and dopamine, it does share some effects with stimulant drugs, most clearly a higher resting heart rate. That is covered in the safety section below.
Tesofensine in Clinical Trials: Results and Data
The key obesity study is a randomised, double-blind, placebo-controlled phase 2 trial published in The Lancet in 2008. It enrolled 203 adults with obesity, who took 0.25 mg, 0.5 mg or 1.0 mg of tesofensine, or a placebo, once daily for 24 weeks. Every group also followed a reduced-calorie diet.
| Group (24 weeks, with diet) | Weight loss compared with placebo | Notes |
|---|---|---|
| Placebo | About 2% of body weight lost | The reference group |
| Tesofensine 0.25 mg | About 4.5 percentage points more | Smallest effect |
| Tesofensine 0.5 mg | About 9 percentage points more | No rise in blood pressure; heart rate up about 7 beats per minute |
| Tesofensine 1.0 mg | About 10.5 percentage points more | Little extra over 0.5 mg; more side effects |
Two things stand out. The response was dose-dependent up to 0.5 mg, and the jump from 0.5 mg to 1.0 mg added little weight loss but more side effects. The trial also measured waist size and body composition, which improved along with body weight.
The authors described the weight loss at 0.5 mg and 1.0 mg as roughly twice what the obesity drugs approved at the time, such as sibutramine and orlistat, achieved. That is a comparison across separate trials, not a head-to-head study, and newer GLP-1 drugs have changed the picture since then.
The limits matter too. The trial ran for six months with about 200 people. It shows what happens to most people over months, not what happens to rare individuals or over years.
Doses Used in Studies, Timing and Combinations
Tesofensine has no approved dose because it is not an approved medicine. The figures below are the doses used in research and the doses people commonly report, not a recommendation.
| Item | Details |
|---|---|
| Route | Oral, once daily (tablet or capsule); not injected |
| Doses tested in the Lancet trial | 0.25 mg, 0.5 mg and 1.0 mg once daily |
| Trial length | 24 weeks |
| 1.0 mg dose | Little extra weight loss over 0.5 mg, more side effects |
| Commonly reported doses | 0.25-0.5 mg once daily |
| 8-12 week “cycles” with breaks | An online convention; not tested in trials |
| Long-term use | Not studied; long-term safety unknown |
Timing and the Long Half-Life
Tesofensine has a very long half-life, roughly a week or more in pharmacokinetic studies. Levels build up slowly over weeks of daily dosing and fall slowly after the last dose. That means the full effect of any dose takes weeks to show, side effects can appear late, and they can linger after stopping. It also means the time of day matters less than with short-acting stimulants, although people who sleep poorly on it often take it in the morning.
What Not to Combine It With
Tesofensine already raises heart rate. Adding other drugs that act on the same brain chemicals adds to that strain and raises the risk of interactions. Avoid combining it with:
- Stimulants and fat burners, including yohimbine, clenbuterol, high-dose caffeine and pre-workouts
- ADHD medicines and other stimulant drugs
- Antidepressants (SSRIs, SNRIs, MAO inhibitors), tramadol and other drugs that act on serotonin
- Other weight-loss drugs
Side Effects and Safety
In the Lancet trial, the most common side effects were dry mouth, nausea, constipation, hard stools, diarrhoea and insomnia. They were generally more common at higher doses, which is one reason the 1.0 mg dose looked like a poor trade. Our article on tesofensine side effects covers each one and how to manage it.
Heart Rate and Blood Pressure
Over 24 weeks, blood pressure did not rise at 0.25 mg or 0.5 mg. Resting heart rate did rise, by about 7 beats per minute at 0.5 mg. So tesofensine is not free of cardiovascular effects: it spares blood pressure at the lower doses in the short term, but it does speed up the heart.
That matters because of sibutramine, a serotonin-noradrenaline reuptake inhibitor for weight loss that was withdrawn from the US and European markets in 2010 after a large trial found more non-fatal heart attacks and strokes in people with existing cardiovascular disease. No trial has measured heart attacks or strokes on tesofensine over years, so its long-term heart safety is unknown.
Who Should Avoid It
- People with heart disease, an arrhythmia, high blood pressure or a previous stroke
- People with a history of depression, bipolar disorder, anxiety disorders, psychosis or eating disorders
- Anyone taking the drugs listed in the combinations section above
- Anyone who is pregnant, breastfeeding or under 18
Compared with approved options, the gap is large. GLP-1 drugs such as semaglutide are approved, made to pharmaceutical standards and backed by years of safety data. Our guide to the best peptides for weight loss covers those alternatives.
Where Tesofensine Is Sold
Tesofensine is not approved by the FDA or the European Medicines Agency, so it is not available on prescription in the US or Europe. It is sold by research-chemical vendors, labelled for research use only, and the rules on buying it differ by country. Check your local regulations first.
SwissChems and NextChems both list it. A certificate of analysis from independent testing gives some assurance about what a batch contains, but it does not make the product safe to take, and everything above about side effects still applies. Speak with a healthcare professional before using any weight-loss drug.
Pros
- Exceptional purity & testing (≥98%)
- Pharmaceutical-style packaging for stability
- Broad catalog across peptides & nootropics
- Strong reputation & consistency across years
Cons
- Some items frequently out of stock due to high demand
- Limited long-term data for some compounds
Pros
- Publishes analytical reports using methods including LC-MS/MS, HPLC-UV/MS, and GC-MS.
- Shipping coverage includes the US, Canada, Europe, South Asia, the Middle East, and other regions.
- Relatively competitive pricing.
Cons
- Customer-reported concerns regarding lost or delayed international shipments.
- Smaller research catalog than other brands on the market
The Bottom Line
Tesofensine produced real, dose-dependent weight loss in trials by curbing appetite, but it is an unapproved oral drug that raises heart rate and has no long-term safety data.
- In the 24-week Lancet trial, 0.5 mg and 1.0 mg daily with a reduced-calorie diet produced roughly 9-11% more weight loss than placebo; 1.0 mg added little over 0.5 mg but brought more side effects.
- It works mainly by lowering appetite through serotonin, noradrenaline and dopamine. It is taken by mouth, not injected, and its long half-life means effects build and fade over weeks.
- Blood pressure held steady at the lower doses over 24 weeks, but heart rate rose, long-term safety is unknown, and approved drugs such as GLP-1s have far more safety data behind them.
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