Tesofensine: Doses, Evidence and the Nine-Day Half-Life
Tesofensine turns up in weight-loss discussions filed alongside peptides, which is the first thing to correct: it is not a peptide, and the way it behaves in the body has more in common with a long-acting stimulant than with anything you would reconstitute in a vial. It has real human trial data, a specific and unusual pharmacokinetic profile, and a regulatory status that vendors routinely overstate. This guide covers what was actually dosed, what came out of it, and where the drug legally stands in 2026.
What Tesofensine Actually Is
Tesofensine, originally coded NS2330, is a small-molecule triple monoamine reuptake inhibitor. It blocks the transporters that clear dopamine, norepinephrine and serotonin from the synaptic cleft, so all three neurotransmitters remain active longer. That is a central nervous system mechanism, and appetite suppression is downstream of it rather than the design goal.
The drug was developed first for Alzheimer disease and then for Parkinson disease. The ADVANS study tested it in advanced Parkinson disease with motor fluctuations, and a separate randomised trial ran it in early Parkinson disease at 0.25, 0.5 and 1.0 mg daily. The neurological programs did not deliver, but weight loss showed up consistently enough across them to justify a dedicated obesity program. That history explains the dose ladder: the obesity trial reused doses already characterised in CNS work.
It is worth being blunt about the category error this causes. Because tesofensine is sold by the same gray-market vendors who list BPC-157 and TB-500, buyers often assume peptide-like assumptions apply: short half-life, subcutaneous injection, mild systemic footprint. None of those hold here. For an orientation to the drugs it actually competes with, see our peptides for weight loss overview.
Tesofensine Dosage: What Was Studied
Three doses have human obesity data, all taken orally once daily. The table below is the trial ladder, not a recommendation, and the evidence column is the part to read first.
| Daily dose | Mean weight loss at 24 weeks | Notes |
|---|---|---|
| Placebo + diet | 2.0% | The diet program alone accounts for this |
| 0.25 mg | 4.5% | No significant blood pressure change |
| 0.5 mg | 9.2% | Dose carried forward; heart rate +7.4 bpm |
| 1.0 mg | 10.6% | Small efficacy gain, worse tolerability |
The step from 0.5 mg to 1.0 mg buys about 1.4 percentage points of weight loss. That is the clearest argument in the dataset against dose escalation, and it is why 0.5 mg became the development dose rather than the maximum tested.
Two things the trials do not tell you. There is no published titration schedule for obesity comparable to the step-ups used with compounded semaglutide, because the fixed doses were assigned from the start. And there is no data past 24 weeks in the Phase 2 program, so questions about durability, weight regain and tolerance have no answer.
The Phase 2 Trial in Detail
The pivotal obesity evidence is a randomised, double-blind, placebo-controlled trial of 203 adults with obesity across five Danish obesity management centres, published in The Lancet in 2008. Participants took placebo or tesofensine at one of the three doses once daily for 24 weeks with a diet program. 161 people, 79 percent, completed.
The authors framed the 0.5 mg result as potentially double the weight loss of the drugs approved at that time, with the explicit caveat that efficacy and safety needed confirmation in Phase 3. That caveat is doing a lot of work in 2026, because the comparison class changed underneath it. In 2008, doubling the available drugs meant beating orlistat and sibutramine. Against today’s GLP-1 medications, a 9.2 percent result is mid-table.
A Phase 3 program of roughly 372 patients was later run through a Mexican partner and reported approximately 10 percent mean weight loss at 24 weeks. That the number reproduced is genuinely a point in the drug’s favour. It is also the extent of the confirmatory evidence.
The 220-Hour Half-Life and Why It Matters
Tesofensine has a terminal half-life of about 220 hours, roughly nine days, with low total body clearance after oral dosing. Its N-desmethyl metabolite NS2360 is the only metabolite found in human plasma and lasts longer still, approximately 374 hours or sixteen days, contributing 31 to 34 percent of parent exposure at steady state.
Three practical consequences, none of which show up in vendor copy:
- Steady state takes weeks, not days. Plasma levels keep climbing for well over a month on a fixed daily dose, so early tolerability is a poor predictor of how the drug will feel at week six.
- Stopping is slow. Discontinuing because of insomnia or a racing heart does not produce relief the next day. Meaningful clearance of the parent compound takes several weeks and the metabolite longer.
- Missed doses matter far less than with a short-acting drug, and doubling up to compensate is straightforwardly a bad idea, since the accumulated exposure has nowhere to go.
This is the single largest behavioural difference between tesofensine and the injectable peptides people compare it to. A weekly GLP-1 washes out in about five weeks; a reconstituted research peptide often clears in minutes to hours. A drug that keeps accumulating for a month rewards patience and punishes self-titration.
Side Effects and the Cardiovascular Signal
Reported adverse events in the Phase 2 trial were dry mouth, nausea, constipation, hard stools, diarrhoea and insomnia. Dry mouth and insomnia are direct consequences of monoamine reuptake inhibition and are the usual reasons people stop.
The cardiovascular finding is more consequential. At 0.5 mg, heart rate rose 7.4 beats per minute versus placebo, a statistically significant difference, while systolic and diastolic blood pressure did not change significantly at 0.25 or 0.5 mg. A sustained resting heart-rate increase of that size is not trivial in a population that frequently already has hypertension or metabolic disease.
The developers took that signal seriously enough to build a fixed combination of tesofensine with the beta-blocker metoprolol, developed under the name Tesomet and studied in hypothalamic obesity and Prader-Willi syndrome. Designing a combination product specifically to counteract your own drug’s heart-rate effect is an honest admission of where the risk sits. For general context on drug side effects in this category, see our peptide side effects guide.
Regulatory Status in 2026
Tesofensine is not approved by the FDA for any indication. It is not an approved obesity drug in the United States, and there is no compounding pathway for it, since a substance with no US approval and no monograph does not qualify.
In Mexico, the picture is more advanced but frequently misdescribed. The regulator COFEPRIS issued a favourable technical opinion in 2023, which the sponsor stated plainly was neither a market authorisation nor a rejection, but one step in the review of a new molecule. Following further interaction with the regulator, the applicant revised and planned to resubmit the dossier. As of this writing, the accurate statement is that tesofensine has been under active review in Mexico with a favourable interim opinion, not that it is approved there. Anyone relying on that distinction should verify the current status directly, because it can change without the vendor pages changing.
Everything sold to US buyers as tesofensine capsules or tablets sits outside the approved supply chain, with the identity, purity and dose accuracy problems that implies. Compare that to the approved options on our FDA-approved peptides list.
Tesofensine vs GLP-1 Medications
| Tesofensine | Semaglutide 2.4 mg | Tirzepatide | |
|---|---|---|---|
| Class | Triple monoamine reuptake inhibitor | GLP-1 receptor agonist | GIP/GLP-1 dual agonist |
| Route | Oral, once daily | Subcutaneous, weekly | Subcutaneous, weekly |
| Mean weight loss | ~9-10% at 24 weeks | ~15% at 68 weeks | ~21% at 72 weeks |
| US approval | None | Approved | Approved |
| Main drawback | Heart rate, insomnia, 9-day half-life | GI side effects, cost | GI side effects, cost |
These are cross-trial comparisons across different populations, durations and eras of trial design, so the percentages are indicative rather than head-to-head. No trial has ever run tesofensine against a GLP-1 directly.
The strongest argument people make for tesofensine is that it is a tablet. That argument aged badly in April 2026, when orforglipron was approved as the first oral small-molecule GLP-1 receptor agonist for weight management. There is now a legal, prescribed, oral option, which removes the main practical reason to source an unapproved one. See our orforglipron guide and which GLP-1 is best for weight loss.
Who Should Stay Away From It
A monoamine reuptake inhibitor with a nine-day half-life carries interaction risk that a peptide does not. Anyone taking an SSRI, SNRI, MAO inhibitor, tricyclic, stimulant ADHD medication or triptan is combining serotonergic or catecholaminergic drugs with a long-acting one, and the accumulation makes the exposure hard to unwind if something goes wrong.
Existing tachycardia, arrhythmia, uncontrolled hypertension, coronary disease, glaucoma, and a history of insomnia or anxiety disorders are all reasonable reasons to rule it out. So is pregnancy or trying to conceive, since the compound persists for weeks after the last dose.
The Bottom Line
Tesofensine has better human evidence than most things sold through research-chemical channels: a properly designed 203-person randomised trial published in a major journal, a dose-response relationship, and a Phase 3 program that reproduced the effect size. That puts it well above the typical gray-market compound.
It also has no US approval, a nine-day half-life that makes mistakes slow to correct, a documented heart-rate increase significant enough that its own developers built a beta-blocker combination around it, no data beyond 24 weeks, and an efficacy figure that now sits below two approved injectables and alongside an approved oral. The evidence is real. The case for choosing it over a prescribed alternative in 2026 is much weaker than the evidence alone suggests.
Frequently Asked Questions About Tesofensine
No. Tesofensine is a small-molecule triple monoamine reuptake inhibitor, closer in kind to a stimulant antidepressant than to anything on a peptide vendor list. It blocks the transporters that clear dopamine, norepinephrine and serotonin from the synapse. Peptides like semaglutide and tirzepatide are large chains of amino acids that act on gut hormone receptors and have to be injected. Tesofensine is an oral tablet. The two categories share a shelf in the gray market and almost nothing else, which matters because the side-effect profile and the drug interaction risks come from the stimulant side of pharmacology, not the GLP-1 side.
The Phase 2 obesity trial randomised 203 adults to placebo or tesofensine at 0.25 mg, 0.5 mg or 1.0 mg once daily for 24 weeks alongside a diet program. The 0.5 mg arm is the dose the developers carried forward, because 1.0 mg produced more weight loss but a worse tolerability and cardiovascular picture. Once daily is not a convenience choice: the half-life is roughly nine days, so dosing more often would stack exposure without adding effect.
Over 24 weeks with diet, mean weight loss was 2.0 percent on placebo, 4.5 percent at 0.25 mg, 9.2 percent at 0.5 mg and 10.6 percent at 1.0 mg. That was a Phase 2 result in 203 people, 79 percent of whom completed. The later Phase 3 program run in Mexico, roughly 372 patients, reported about 10 percent at 24 weeks, which is consistent. For scale: semaglutide 2.4 mg produced about 15 percent at 68 weeks and tirzepatide about 21 percent, so tesofensine is not in the same efficacy tier as the top GLP-1s despite the way it is often marketed.
About 220 hours, roughly nine days. The active N-desmethyl metabolite NS2360 is longer still at approximately 374 hours, around sixteen days, and sits at 31 to 34 percent of parent exposure at steady state. Two practical consequences follow. It takes weeks of daily dosing to reach steady state, so judging the drug after one week tells you very little. And if you stop because of a side effect, the drug is still in you for well over a month.
No. Tesofensine has never been approved in the United States for obesity or anything else. It began life as NS2330, a candidate for Alzheimer disease and Parkinson disease, and was redirected to obesity after weight loss showed up consistently in those CNS trials. Anything sold as tesofensine to a US buyer today is unapproved, and the capsules and tablets circulating through research-chemical vendors carry no verified identity or dose.
Not in the sense that word usually carries. Mexico’s regulator COFEPRIS issued a favourable technical opinion in 2023, which the developer described explicitly as neither a market authorisation nor a rejection but a step in the review of a new molecule. The applicant subsequently revised the dossier after further interaction with the regulator. Treat any vendor claim of Mexican approval as a claim about a procedural milestone, not a finished authorisation, and check the current status yourself before relying on it.
Heart rate, yes. In the Phase 2 trial the 0.5 mg dose increased heart rate by 7.4 beats per minute versus placebo. Neither the 0.25 mg nor the 0.5 mg dose produced a significant rise in systolic or diastolic blood pressure. That cardiovascular signal is why the drug has been studied in combination with the beta-blocker metoprolol, a fixed combination given the development name Tesomet, specifically to blunt the heart-rate effect in hypothalamic obesity and Prader-Willi syndrome populations.
The adverse events reported most often in the Phase 2 trial were dry mouth, nausea, constipation, hard stools, diarrhoea and insomnia. Dry mouth and insomnia are the signature of monoamine reuptake inhibition and are the two most likely to make someone stop. The long half-life compounds the insomnia problem: a dose taken too late in the day cannot be cleared overnight. Add the heart-rate effect above, and the practical risk profile is that of a long-acting stimulant.
Different mechanism, different evidence base, different regulatory reality. Semaglutide and tirzepatide are approved GLP-1-based injectables with large Phase 3 programs and cardiovascular outcome data behind them, producing roughly 15 and 21 percent mean weight loss respectively in obesity trials. Tesofensine is an unapproved oral monoamine reuptake inhibitor with a 24-week Phase 2 result near 9 to 10 percent and no outcome data. If the appeal is that it is oral, note that orforglipron, an oral non-peptide GLP-1 receptor agonist, was approved in April 2026 and is a legal prescription route to the same goal.
There is no human trial of tesofensine combined with semaglutide, tirzepatide or any other GLP-1 agonist, so nobody can tell you the effect size or the safety margin of that combination. The theoretical concern is not the weight loss, it is the overlap: both suppress appetite and both cause nausea, and tesofensine adds a heart-rate increase and a nine-day half-life on top. Combining an unapproved stimulant with a prescription injectable is the kind of decision that needs a prescriber who knows about both, not a forum protocol.