Tesofensine (NS2330): SNDRI Small Molecule for Obesity#

Tesofensine is a small-molecule serotonin-noradrenaline-dopamine reuptake inhibitor (SNDRI), not a peptide, originally developed by NeuroSearch (Denmark) under the codename NS2330 and now advanced by Saniona for the treatment of obesity. In the 24-week Phase 2 obesity trial reported by Astrup and colleagues in The Lancet (2008; PMID 18950853; DOI: 10.1016/S0140-6736(08)61525-1)¹, tesofensine 1.0 mg produced approximately 12.8% mean total body weight loss at 24 weeks - roughly twice the magnitude reported for then-approved obesity drugs. Last verified June 2026.

What is Tesofensine?#

Tesofensine (development code NS2330) is a triple monoamine reuptake inhibitor that blocks the presynaptic reuptake of serotonin, noradrenaline (norepinephrine), and dopamine in the central nervous system¹. Originally synthesized at NeuroSearch in Denmark in the 1990s, it was first investigated as a treatment for Parkinson's disease and Alzheimer's disease, where it failed to meet primary efficacy endpoints. Subsequent Phase 2 obesity trials revealed an unexpectedly large weight-loss signal, redirecting clinical development toward metabolic indications¹.

Saniona acquired the program from NeuroSearch and has continued development primarily through a combination product called Tesomet - tesofensine paired with the cardioselective beta-1 blocker metoprolol, intended to mitigate the heart-rate increase seen with tesofensine monotherapy².

Tesofensine is administered orally, once daily. It is not a peptide and does not require subcutaneous injection.

Mechanism of Action#

Tesofensine inhibits the presynaptic reuptake of three monoamine neurotransmitters - serotonin (5-HT), noradrenaline, and dopamine - by binding to and blocking their respective transporters (SERT, NET, and DAT)¹. By preventing neuronal reuptake, tesofensine increases synaptic concentrations of all three neurotransmitters.

How Triple Reuptake Inhibition Drives Weight Loss#

The weight-loss effect appears to be mediated primarily through central nervous system pathways:

• Hypothalamic appetite suppression: Increased noradrenergic and dopaminergic tone in hypothalamic feeding centers reduces appetite drive
• Reward / hedonic eating modulation: Elevated dopamine signaling in mesolimbic pathways is thought to reduce the rewarding value of palatable food
• Energy expenditure: Sympathomimetic effects on noradrenergic tone modestly increase resting energy expenditure and heart rate

Preclinical work suggests the dopaminergic component is a strong driver of food intake reduction, distinguishing tesofensine from selective serotonin reuptake inhibitors (SSRIs) and serotonin-noradrenaline reuptake inhibitors (SNRIs), which have weaker effects on body weight¹.

Mechanism Contrast With Incretin Therapies#

Unlike semaglutide, tirzepatide, and retatrutide - peptide drugs that act peripherally through gut-derived hormone receptors (GLP-1, GIP, glucagon) - tesofensine acts centrally on monoamine neurotransmission. The two drug classes have non-overlapping mechanisms, raising the theoretical (but not clinically tested) possibility of combination use.

Research Overview#

The pivotal published evidence for tesofensine in obesity is the Phase 2 dose-ranging trial by Astrup et al., published in The Lancet in 2008 (PMID 18950853)¹. This 24-week randomised, double-blind, placebo-controlled study enrolled 203 adults with obesity at five Danish sites, randomising them to placebo or tesofensine 0.25 mg, 0.5 mg, or 1.0 mg once daily, all on a hypocaloric diet. Reported placebo-subtracted weight loss was approximately 4.5% at 0.25 mg, 9.2% at 0.5 mg, and 10.6% at 1.0 mg. Total body weight reduction in the 1.0 mg group was approximately 12.8% - a magnitude that, at the time, exceeded that of any then-approved anti-obesity drug¹.

Subsequent development by Saniona has focused on the combination product Tesomet (tesofensine + metoprolol) in obesity and in rare metabolic conditions including hypothalamic obesity and Prader-Willi syndrome². Topline results from Saniona's TIPO and exploratory studies have been disclosed via company press releases and conference presentations; peer-reviewed late-stage publications were not yet indexed in PubMed under verifiable trial identifiers as of June 2026.

Important Considerations#

• Investigational small-molecule drug - not FDA-approved for any indication as of June 2026
• Not a peptide; not interchangeable with GLP-1 receptor agonists
• Administered orally once daily; no injection involved
• Earlier development in Parkinson's disease and Alzheimer's disease did not meet efficacy endpoints
• Sympathomimetic side effects - especially heart-rate elevation and blood-pressure changes - are the principal safety concern and motivated the development of the Tesomet combination
• Material from research-chemical vendors is not pharmaceutical grade and is not legally usable in humans
• Mood and sleep-related effects (insomnia, irritability) are common and dose-dependent

Key Research Findings#

Effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trial, published in The Lancet (Astrup A et al., 2008; PMID 18950853)¹:

• 24-week Phase 2 trial in 203 adults with obesity randomised to placebo, 0.25 mg, 0.5 mg, or 1.0 mg tesofensine on a hypocaloric diet
• Placebo-subtracted weight loss of approximately 4.5% (0.25 mg), 9.2% (0.5 mg), and 10.6% (1.0 mg)
• 1.0 mg dose: approximately 12.8% mean total body weight reduction at 24 weeks
• Most common adverse events were dry mouth, nausea, constipation, hard stools, diarrhoea, and insomnia
• Heart rate increased by a mean of approximately 7-8 bpm at higher doses

References#

Related Reading#

• Tesofensine molecular structure and properties
• Tesofensine research studies and evidence
• Tesofensine dosing information
• Tesofensine side effects profile
• Tesofensine risks and legal status
• Semaglutide research guide
• Retatrutide research guide
• Tirzepatide research guide

Footnotes#

1. 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. The Lancet. 2008;372(9653):1906-1913. PMID: 18950853. DOI: 10.1016/S0140-6736(08)61525-1. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

2. Saniona AB. Tesofensine / Tesomet pipeline. https://saniona.com/pipeline/tesofensine. Accessed June 2026. ↩ ↩²