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Small molecule drug (not a peptide)Human trialsNot FDA approved

Tesofensine

Tesofensine

Last reviewed October 27, 2026 · 16 sources · Written for general readers · Compare with another compound →

The bottom line

Tesofensine is a pill, not a peptide, that boosts three brain chemicals and caused real weight loss in trials, mostly by cutting appetite. It also raises heart rate, disturbs sleep, and its main obesity trial drew a formal expression of concern over how side effects were recorded. It is not FDA approved, and as of our search Mexico had not approved it either.

Where the evidence stands

What it is

Tesofensine is a small molecule drug taken by mouth. It is not a peptide. FDA's substance registry lists it under CAS number 195875-84-4.[1]

It was first tested in people with Parkinson's and Alzheimer's disease. Patients in those trials lost weight, so it was then developed for obesity.[2]

The Danish company Saniona licensed it to Medix for Mexico and Argentina. Medix ran phase 3 obesity trials and applied for approval in Mexico.[3][4]

It has also been tested as Tesomet, a pill that pairs tesofensine with metoprolol, a drug that slows the heart, for obesity caused by damage to the hypothalamus, the brain's appetite center.[5]

Name
Tesofensine (Tesofensine)
Other names
NS2330, NS 2330, Tesomet (combination with metoprolol)
Type
Small molecule drug (not a peptide)
CAS number
195875-84-4
Formula
C17H23Cl2NO
Molecular weight
About 328.3 g/mol

How it works

Tesofensine blocks the recycling of three chemical messengers in the brain: norepinephrine, dopamine and serotonin.[6]

  • Blocking recycling leaves more of these messengers active between nerve cells.[6]
  • In a two week study in men, it made people feel fuller and want to eat less, and it nudged up calorie burn at night.[7]
  • In obese rats, its appetite effect depended mostly on norepinephrine signaling through alpha1 receptors, with a smaller role for dopamine D1 receptors.[8]
  • It also raised heart rate in trials, a common effect of drugs that boost norepinephrine.[6][2]

Appetite loss seems to be the main driver of weight loss. The brain details come mostly from rat studies.

What the research shows

We keep animal and human evidence apart. A result in animals is a reason to study something in people, not proof that it works in people.

Animal and lab studies

Rat and mouse studies point to appetite control in the brain

  • In diet induced obese rats given the drug under the skin for 16 days, treated rats weighed clearly less than untreated rats, mostly because they ate much less.[8]
  • Blocking alpha1 adrenergic receptors almost fully reversed the drop in eating, and blocking dopamine D1 receptors partly reversed it. Blocking serotonin 2A and 2C receptors had no effect.[8]
  • A 2024 study found it caused more weight loss in obese rats than in lean rats, and in mice it quieted a group of GABA nerve cells in the lateral hypothalamus that drive feeding.[14]
  • In that study it caused little of the repetitive head movement seen with phentermine, a dopamine boosting diet pill, and it did not seem to change how mice perceived sweet taste.[14]

Limit: Rodent brain findings help explain the appetite effect but do not prove the same happens in people.

Human studies

Clear weight loss, but the key trial has data concerns

  • Obesity, 2008: 203 Danish adults with obesity who also dieted took a daily pill or placebo for 24 weeks. Weight fell about 4.5 to 10.6 percent depending on dose, versus 2 percent on placebo. About 79 percent finished.[6]
  • In that trial, dry mouth, nausea, constipation, hard stools, diarrhea and trouble sleeping were most common. Heart rate rose by about 7 beats per minute in one dose group.[6]
  • In 2013 The Lancet issued an expression of concern, a formal warning to readers, about that trial.[9] A Danish inspection found consent problems at one site and side effects that were not reliably recorded, though the main weight results matched the records.[10]
  • Short term, 2010: 32 overweight or moderately obese men took the pill or placebo for two weeks. Fullness rose, expected food intake fell, they lost about 1.8 kg more than placebo, and fat burning rose by about 18 grams a day. Total daily calorie burn did not change.[7]
  • Parkinson's and Alzheimer's: pooled data from four 14 week trials in about 970 patients showed up to about 3 percent weight loss with no diet program. Heart rate rose up to about 7 beats per minute, and blood pressure did not change.[2]
  • Advanced Parkinson's: in a 14 week placebo controlled trial, only some dose levels improved symptoms, and stomach and mental side effects rose at higher doses.[13]
  • Hypothalamic obesity: in a 24 week trial of 21 adults, Tesomet led to about 6 percent more weight loss than placebo. Trouble sleeping (50 percent versus 13 percent), dry mouth (43 percent versus 0) and headache (36 percent versus 0) were common, and one person had a serious worsening of anxiety.[5]
  • Abuse potential: 52 recreational stimulant users given single doses could feel its effects compared with placebo, but less than amphetamine. The authors judged its abuse risk to be low.[11]
  • Saniona says the phase 3 trials in Mexico confirmed the earlier results, but we did not find them published in a peer reviewed journal.[3]

Limit: Most trials were short, the main obesity trial has documented record keeping problems, and the phase 3 data are not published.

Claims check

The most common claims about this compound, and what studies actually found. Verdicts rate the evidence, not whether you should use it.

Causes major fat loss

Shown in people

In a 24 week placebo controlled trial of 203 adults with obesity who also dieted, people on the pill lost about 4.5 to 10.6 percent of body weight depending on dose, versus 2 percent on placebo.[6] Pooled data from 14 week trials in about 970 people with Parkinson's or Alzheimer's showed up to about 3 percent weight loss without a diet program.[2] The main obesity trial later drew an expression of concern over record keeping, though inspectors found the weight results matched the records.[9][10]

Crushes appetite

Mixed results

In a two week trial of 32 overweight or moderately obese men, the pill raised feelings of fullness and lowered how much people expected to eat, compared with placebo. They lost about 1.8 kg more than the placebo group even though the study tried to keep weight stable.[7] This was one small, short study, though appetite loss fits the weight results of the longer trials.[6]

Speeds up metabolism

Mixed results

In the same two week trial of 32 men, total calories burned over 24 hours did not differ from placebo. Calorie burn at night was about 4.6 percent higher, and the body burned about 18 grams more fat a day.[7] The authors judged appetite to be the bigger effect.

Gives energy without stimulant side effects

No benefit in trials so far

Trials show stimulant type effects. Heart rate rose by up to about 7 beats per minute, and trouble sleeping and dry mouth were common.[6][2] In 52 recreational stimulant users given single doses, it caused noticeable drug effects compared with placebo, though less than amphetamine.[11] WADA bans it as a stimulant during competition.[12]

Sharpens the brain and helps Parkinson's

Mixed results

It was first developed for Parkinson's and Alzheimer's.[2] In a 14 week placebo controlled trial in advanced Parkinson's, one dose level improved symptom scores and another cut daily off time by about 68 minutes, but the other doses had no clear effect, and stomach and mental side effects were more common.[13] We found no study testing it for focus or memory in healthy people.

Known risks and side effects

  • Faster heart rate. Heart rate rose by up to about 7 beats per minute in trials, which matters for people with heart disease.[6][2]
  • Sleep problems, dry mouth and anxiety. In one small trial, half the people on Tesomet had trouble sleeping and 43 percent had dry mouth, and one person had a serious worsening of anxiety.[5]
  • Side effects may be undercounted. Danish inspectors found that recurring problems such as headache, stress and depression were not reliably recorded in the main obesity trial.[10]
  • Stimulant effects and sport bans. Stimulant users could feel its effects after a single dose, and WADA lists it as a stimulant banned during competition.[11][12]
  • Unregulated online products. Tesofensine is not FDA approved and does not appear on FDA's compounding nomination list, so products sold online are unapproved and unchecked.[15]

Regulatory status

Today: Tesofensine is not FDA approved. In Mexico, Medix resubmitted its application to the regulator COFEPRIS in February 2025, and we found no announcement of approval since.[4] WADA bans it during competition as a stimulant.[12]

  1. The Lancet published the 24 week phase 2 obesity trial.[6]
  2. The Lancet issued an expression of concern about that trial.[9]
  3. The COFEPRIS committee gave a favorable opinion for obesity use.[3]
  4. Saniona said Medix still had not received approval in Mexico.[16]
  5. Medix resubmitted an updated application to COFEPRIS.[4]

Sources

  1. U.S. FDA and NCATS Global Substance Registration System (GSRS). Tesofensine, UNII BLH9UKX9V1. FDA GSRS
  2. Astrup A, Meier DH, Mikkelsen BO, Villumsen JS, Larsen TM. Weight loss produced by tesofensine in patients with Parkinson's or Alzheimer's disease. Obesity (Silver Spring). 2008;16(6):1363-1369. PMID 18356831
  3. Saniona AB. Tesofensine (pipeline page). Last modified February 8, 2024. Company page
  4. Saniona AB. Medix has resubmitted tesofensine application to COFEPRIS. Company release. February 20, 2025. Company release
  5. Huynh K, Klose M, Krogsgaard K, Drejer J, Byberg S, Madsbad S, et al. Randomized controlled trial of Tesomet for weight loss in hypothalamic obesity. Eur J Endocrinol. 2022;186(6):687-700. PMID 35294397
  6. Astrup A, Madsbad S, Breum L, Jensen TJ, Kroustrup JP, Larsen TM. Effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trial. Lancet. 2008;372(9653):1906-1913. PMID 18950853
  7. Sjödin A, Gasteyger C, Nielsen AL, et al. The effect of the triple monoamine reuptake inhibitor tesofensine on energy metabolism and appetite in overweight and moderately obese men. Int J Obes (Lond). 2010;34(11):1634-1643. PMID 20479765
  8. Axel AMD, Mikkelsen JD, Hansen HH. Tesofensine, a novel triple monoamine reuptake inhibitor, induces appetite suppression by indirect stimulation of alpha1 adrenoceptor and dopamine D1 receptor pathways in the diet-induced obese rat. Neuropsychopharmacology. 2010;35(7):1464-1476. PMID 20200509
  9. The Editors. Expression of concern: Effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients. Lancet. 2013;381(9873):1167. PMID 23561987
  10. Retraction Watch. Trial irregularities earn Lancet study of potential weight loss drug tesofensine Expression of Concern. April 9, 2013. News
  11. Schoedel KA, Meier D, Chakraborty B, Manniche PM, Sellers EM. Subjective and objective effects of the novel triple reuptake inhibitor tesofensine in recreational stimulant users. Clin Pharmacol Ther. 2010;88(1):69-78. PMID 20520602
  12. World Anti-Doping Agency. The 2026 Prohibited List. In force January 1, 2026. WADA 2026
  13. Rascol O, et al. Tesofensine (NS 2330), a monoamine reuptake inhibitor, in patients with advanced Parkinson disease and motor fluctuations. Arch Neurol. 2008;65(5):577. PMID 18474731
  14. Pérez CI, Luis-Islas J, Lopez A, et al. Tesofensine, a novel antiobesity drug, silences GABAergic hypothalamic neurons. PLoS One. 2024;19(4):e0300544. PMID 38656972
  15. U.S. Food and Drug Administration. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act. Updated May 14, 2026. FDA list
  16. Saniona AB. Update on tesofensine application. Company release. November 12, 2024. Company release
Medical disclaimer

This page is educational information only. It is not medical advice and does not replace care from a licensed medical provider. Do not use this page to decide whether to take any substance. Talk to a licensed medical provider first.

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