Tesofensine

Tesofensine is a drug taken by mouth ^[12]. It blocks the brain from taking back three chemical messengers: noradrenaline, dopamine and serotonin ^[5]. Chemical messengers carry signals between nerve cells. It is also called NS-2330 ^[17].

A drug company first tested it for brain diseases such as Alzheimer's disease ^{[12] [16]}. It did not help them, but some people lost weight they did not mean to lose ^[12]. The company then tested it as a pill for obesity ^[12]. A later company tested it combined with another drug, metoprolol, for rare kinds of obesity ^{[3] [9]}. One of these is hypothalamic obesity: fast weight gain after injury to the hypothalamus, a part of the brain ^[9].

Tesofensine has no approved use in the US: FDA says it is not eligible for use in pharmacy compounding ^[1]. That means no pharmacy may lawfully make drugs from it. It does not mean a seller may offer it for people, and FDA says a company that sent it to pharmacies broke federal law ^[1]. Checked 26 October 2026.

A pharmacy may make a drug from a bulk ingredient only in three cases ^[2]. The ingredient has an official quality standard, is part of an FDA-approved drug, or is on a list FDA keeps ^[2]. FDA's 2025 letter puts tesofensine among ingredients that are not eligible ^[1].

In 2021, FDA gave orphan drug status to tesofensine combined with metoprolol ^{[3] [4]}. Orphan status marks a drug being developed for a rare disease ^[3]. The two uses were Prader-Willi syndrome and hypothalamic obesity ^{[3] [4]}. That is not approval: both FDA records say the combination is not approved for these uses ^{[3] [4]}.

A 2009 review says FDA backed plans for larger obesity trials of tesofensine ^[12]. A 2008 news report says its maker was seeking approval in the US and Europe ^[16]. Backing a trial plan, or seeking approval, is not approval.

The evidence grade is moderate-human: one controlled trial in obese adults, published in full, found more weight loss than a dummy pill over 24 weeks ^[5]. That trial later drew an expression of concern from its journal, so the main result is in question ^[6].

In that trial, 203 obese adults in Denmark went on a low-calorie diet ^[5]. They took tesofensine or a dummy pill for 24 weeks ^[5]. People on tesofensine lost between 4.5% and 10.6% of their weight, against 2.0% on the dummy pill ^[5]. The authors said larger trials must confirm the results ^[5].

In 32 overweight or obese men, two weeks of tesofensine cut appetite ^[7]. They lost 1.8 kg more than men on a dummy pill ^[7]. In another trial, tesofensine made people feel fuller, but the effect faded as weight came off ^[8]. In 21 adults with hypothalamic obesity, tesofensine with metoprolol led to 6.3% more weight loss than a dummy pill over 24 weeks ^[9]. That trial was small, and its main goal was to look for harms ^[9].

In obese rats, tesofensine cut food intake and weight and changed brain dopamine ^{[10] [11]}. When the rats stopped it, they ate more and gained weight again ^[11]. These are animal results, not results in people.

No pharmacy may lawfully make tesofensine, and FDA has approved no use of it ^{[1] [3]}. There is no legal route to it in the US today.

The three studies of it in our sources took place in Denmark and ended by 2020 ^{[13] [14] [15]}. Any open trial appears in the trials block below, with the date the official registry was last checked.

One way of getting tesofensine shows up in federal records: pharmacies that make it although the law does not allow it ^[1]. In December 2025, FDA sent a warning letter to a Florida company that sells drug ingredients ^[1]. FDA says the company sent tesofensine to pharmacies that wanted to make drugs from it ^[1]. FDA says tesofensine may not be used that way, so the company broke federal law ^[1].

FDA also found the company did not check its suppliers well ^[1]. It said the drug ingredients the company handled were adulterated ^[1]. Adulterated means not made under the quality rules the law requires ^[1]. Our sources hold no federal record of other ways tesofensine reaches people.