The short answer
Tesofensine is not a peptide. It is a small synthetic molecule — a substituted tropane, chemically related to older stimulant-type compounds — with a molecular weight of about 328 Da, roughly a tenth of semaglutide's. It contains no amino acids. It appears in peptide vendors' catalogues and in “peptide stack” discussions because it is sold as a research chemical for weight loss and is taken orally, but classifying it as a peptide is simply wrong, and the distinction matters for everything from how it is absorbed to what kind of side effects to expect.
What it actually is
Tesofensine (NS2330) was developed by NeuroSearch in Denmark in the 1990s as a treatment for Parkinson's and Alzheimer's disease. It is a triple monoamine reuptake inhibitor: it blocks the transporters that clear serotonin, noradrenaline and dopamine from synapses, raising all three. The neurological programmes failed, but participants lost weight, and the compound was repurposed for obesity. Its mechanism therefore has nothing in common with GLP-1 or incretin peptides, which act on gut-hormone receptors; it is closer to the appetite suppressants of the sibutramine era, which were withdrawn over cardiovascular risk.
| Tesofensine | Semaglutide | |
|---|---|---|
| Chemical class | Small molecule (tropane) | 31-residue lipidated peptide |
| Mass | ≈ 328 Da | ≈ 4,114 Da |
| Mechanism | Serotonin/noradrenaline/dopamine reuptake inhibition | GLP-1 receptor agonism |
| Route | Oral, daily | Subcutaneous weekly (or oral daily) |
| Approval (US/CA/EU) | None | Approved |
What the trials showed
The phase 2 TIPO-1 trial (Astrup et al., Lancet 2008; 203 adults with obesity, 24 weeks) reported placebo-subtracted weight loss of about 4.5%, 9.2% and 10.6% at 0.25, 0.5 and 1.0 mg daily — large for the time — with dose-related increases in heart rate and blood pressure, dry mouth, insomnia and mood-related adverse events. Those cardiovascular signals are the class problem for monoamine reuptake inhibitors and are the main reason development in the US and Europe stalled for over a decade. Later trials in Mexico led to a national approval there in 2024, but as of September 2026 tesofensine has not been approved by the FDA, Health Canada or the EMA.
Why it shows up in peptide catalogues
Grey-market vendors sell whatever weight-loss compounds have a following, and tesofensine's decade-old phase 2 numbers, oral dosing and unapproved status make it a natural fit next to retatrutide vials. The pairing creates a false impression that it belongs to the same pharmacological family. It does not: the incretin peptides have cardiovascular outcome trials showing benefit, while tesofensine's defining safety signal is cardiovascular. Anyone comparing the two is comparing a gut-hormone analogue with a stimulant-adjacent monoamine drug.
Status and what this page is not
Tesofensine is unapproved in the US, Canada and the EU, and material sold online as a “research chemical” is unlicensed and of unverified content. This page exists to correct a classification error, not to describe how to obtain or use anything, and it is not medical advice.
Sources and what they cover
These primary studies, official records and standards cover the topics linked below. The scope notes distinguish laboratory findings, human trials and regulatory records. This is a selected bibliography, not a systematic review or verification of every sentence; absence of a study here does not prove that no study exists.
- Astrup et al. (2008) — Tesofensine and bodyweight loss
Human trial of a small-molecule monoamine reuptake inhibitor; not a peptide study.
Relevant sections: The short answer · What it actually is · What the trials showed
- IUPAC Gold Book — peptides
Chemical terminology; no evidence of treatment effectiveness.
Relevant sections: The short answer
FAQ
Is tesofensine a peptide?+
No. It is a small synthetic molecule (about 328 Da) that inhibits serotonin, noradrenaline and dopamine reuptake. It contains no amino acids.
How does tesofensine work?+
By blocking the reuptake of three monoamine neurotransmitters, which suppresses appetite — a mechanism unrelated to GLP-1 peptides.
Is tesofensine approved?+
Not by the FDA, Health Canada or the EMA as of September 2026. It received a national approval in Mexico in 2024.
How much weight loss did tesofensine produce?+
About 10.6% placebo-subtracted at 1.0 mg daily over 24 weeks in the 2008 phase 2 trial, with increases in heart rate and blood pressure.
Can tesofensine be combined with peptides?+
No trial has tested that, and this site does not give combination or dosing guidance.