Tesofensine

A serotonin-noradrenaline-dopamine reuptake inhibitor originally developed for Parkinson's disease, later trialed for obesity. Never approved anywhere.

Tesofensine blocks the reuptake of all three monoamines — noradrenaline, dopamine and serotonin — so all three stay in the synapse longer. It was originally developed for Parkinson's disease and Alzheimer's, failed at both, and the weight loss seen incidentally in those trials is why it exists at all as a topic. Appetite suppression comes from the combined monoamine effect on hypothalamic feeding circuits. Blocking dopamine reuptake is also, unavoidably, the mechanism that gives stimulants their abuse potential and their cardiovascular effects.

A Phase 2 obesity trial reported weight loss but also increased heart rate and other adverse effects. Development continued intermittently (including combination programs) without reaching approval anywhere.

• MODERATE for weight loss in the sense that it works: a phase II trial reported substantial weight reduction over 24 weeks, larger than the obesity drugs available at the time.
• NONE SHOWN for anything else. It failed its original neurological indications, which is how it became available for repurposing in the first place.
• It has never completed phase III for obesity and is not approved in the US, EU or UK. It has been approved in Mexico under the brand Tesomet-adjacent naming for obesity in some contexts — approval in one jurisdiction is not a general safety verdict.
• The blocking issue was cardiovascular: dose-dependent increases in heart rate and blood pressure were consistently observed, and that signal is what has kept it from broader approval.
• Mood changes, irritability and sleep disturbance were reported, consistent with a triple monoamine reuptake inhibitor.

Orally active with a long half-life, so effects accumulate over days rather than acting dose-by-dose — which is precisely why the cardiovascular effects build rather than announce themselves. Human pharmacokinetics are reasonably characterised from the abandoned trial programme, which is more than most compounds in this section can say.

The trial record itself documents the profile: elevated heart rate, insomnia, dry mouth, mood effects — a stimulant-pattern profile from a stimulant-pattern mechanism. Combining it with other stimulants or thyroid compounds stacks cardiovascular load. An unapproved CNS drug with no approved-label safety framework.

• Anyone with cardiovascular disease, arrhythmia or uncontrolled hypertension
• Anyone taking an MAO inhibitor or other serotonergic drug
• Anyone with a psychiatric history, given the mood and agitation reports
• Anyone pregnant or breastfeeding
• Anyone buying it outside a jurisdiction where it is lawfully prescribed

• MAO inhibitors — the combination risk with any monoamine reuptake inhibitor is serotonin syndrome and hypertensive crisis, and this is the interaction to take most seriously.
• Other serotonergic drugs including SSRIs, SNRIs, triptans and tramadol.
• Any stimulant, including caffeine, where cardiovascular effects are additive.
• Blood-pressure medication, which it works against.

Documented interactions with other things people research. A compound not listed here does not mean the combination is safe — only that no specific interaction is on file.

• Heart rate and blood pressure — the specific signal that stalled its development, and it is dose-dependent.
• Mood, agitation and sleep, consistent with monoamine reuptake inhibition.
• Any cardiac symptom — chest pain, palpitations, fainting — as urgent assessment rather than something to track.
• What was actually purchased: it is not approved in most jurisdictions, so grey-market supply is unverified.

The long half-life means effects taper over days rather than stopping. Appetite returns, and weight regain after stopping any appetite-suppressing drug is the pattern across the whole category. No withdrawal syndrome in the dependence sense is established, though monoamine reuptake inhibitors as a class can produce discontinuation effects. Anyone whose blood pressure or heart rate rose during use should have that rechecked afterwards rather than assumed resolved.

US: not FDA-approved; not scheduled. Any product sold for human use is an unapproved drug.

Papers about this compound, not proof of the claims above. A title says what was studied, which is sometimes a negative result or a different question entirely.

• Expression of concern--effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trial
  Lancet, 2013
• Tesofensine, a novel antiobesity drug, silences GABAergic hypothalamic neurons
  PLoS One, 2024
• Tesofensine, a novel triple monoamine re-uptake inhibitor with anti-obesity effects: dopamine transporter occupancy as measured by PET
  Eur Neuropsychopharmacol, 2014

• Tesofensine, a monoamine reuptake inhibitor for the treatment of obesityCurr Opin Investig Drugs · 2009
• Tesofensine, a novel antiobesity drug, silences GABAergic hypothalamic neuronsPLoS One · 2024
• Tesofensine and weight lossLancet · 2009
• Tesofensine and weight lossLancet · 2009
• Weight loss produced by tesofensine in patients with Parkinson's or Alzheimer's diseaseObesity (Silver Spring) · 2008
• 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 ratNeuropsychopharmacology · 2010
• Expression of concern--effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trialLancet · 2013
• Tesofensine induces appetite suppression and weight loss with reversal of low forebrain dopamine levels in the diet-induced obese ratPharmacol Biochem Behav · 2013
• Tesofensine (NS 2330), a monoamine reuptake inhibitor, in patients with advanced Parkinson disease and motor fluctuations: the ADVANS StudyArch Neurol · 2008
• Under-reporting of adverse effects of tesofensineLancet · 2013
• Tesofensine, a novel triple monoamine re-uptake inhibitor with anti-obesity effects: dopamine transporter occupancy as measured by PETEur Neuropsychopharmacol · 2014
• Triple monoamine inhibitor tesofensine decreases food intake, body weight, and striatal dopamine D2/D3 receptor availability in diet-induced obese ratsEur Neuropsychopharmacol · 2012