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Tesofensine

B

lead outcome

Weight loss / obesity

grades vary by outcome ↓

Small molecule (non-peptide)

also called — Tesofensine · NS-2330 (original code)

weight management / obesity (appetite ↓ + energy expenditure ↑)CNS monoamine modulation(originally: neurodegeneration — modest)

The brain drug that lost weight by accident. Tesofensine is one of the register's best serendipity stories — and a mechanistic outlier. Beautiful facts: (1) it was built for Parkinson's and Alzheimer's, worked only modestly there, but made patients lose weight so consistently the whole program pivoted to obesity — a weight-loss effect that was discovered, not engineered; (2) it's a triple monoamine reuptake inhibitor — it raises dopamine, norepinephrine, AND serotonin at once (an antidepressant-style mechanism), utterly unlike the GLP-1/amylin drugs around it; (3) it loses weight two ways at once — cutting appetite and raising energy expenditure. It's a small molecule, not a peptide — with a real cardiovascular caveat.

In brief

Tesofensine (NS-2330) is a small-molecule triple monoamine reuptake inhibitor — it raises dopamine, norepinephrine, and serotonin at once — and its story is a gem of pharmacological serendipity. It was developed for Parkinson's and Alzheimer's, where it worked only modestly, but trial participants lost weight so reliably that the program pivoted entirely to obesity — a weight-loss effect discovered, not designed. A pooled analysis of neurology trials revealed the dose-dependent effect, and a Phase 2 obesity trial (Lancet 2008) showed ~10% weight loss in 24 weeks — about double the approved drugs of that era. Mechanistically it's an outlier here: it works centrally, on two fronts at once (appetite suppression via serotonin, energy expenditure via norepinephrine), rather than through gut incretin or amylin hormones. The honest caveats are real: it's a small molecule (not a peptide), unapproved, its mechanism is cousin to withdrawn appetite drugs (sibutramine), and it carries a cardiovascular signal (raised heart rate). And its headline "twice the weight loss" belongs to a pre-GLP-1 world — today's semaglutide/tirzepatide have reset the bar. So: a fascinating, twice-serendipitous CNS weight-loss drug with a genuinely interesting mechanism — but unapproved, cardiovascularly watchful, and overtaken by the incretin era.

Legal standing, by region

United States

not an approved obesity drug in major markets

not an approved obesity drug in major markets; investigational (reached Phase 2/3). Some regional/combination development has occurred, but no broad approval.

Evidence, by outcome

How we grade →

An honest grade per outcome — drawn from the evidence, not any catalogue. Hype and undemonstrated marketing claims grade low.

OutcomeEvidence base · effectGrade

Weight loss / obesity

Solid Phase 2 — but not Phase 3-confirmed for approval, and the "2×" was pre-GLP-1 (incretins now exceed it)

Phase 2 (Astrup, Lancet 2008): significant at all doses, ~10%/24 wk; "~2× era's drugs"

B

Energy expenditure + appetite (dual mechanism)

Genuinely dual-action; full human mechanism "unresolved"

Respiration-chamber (Sjödin 2010): ↑24-h EE, ↑fat oxidation, ↓appetite

B

Parkinson's / Alzheimer's (original use)

Failed to become a neuro drug — the reason it was repurposed

Four RCTs: limited efficacy

D

Cardiovascular safety

The key caveat — HR increase (mechanistic cousin to withdrawn sibutramine); needs careful CV monitoring

Phase 2: heart rate +~7 bpm (p=0.0001); BP not significantly raised at 24 wk

C

Tolerability

Stimulant-type AEs; dopaminergic component raises theoretical mood/dependence questions

Dry mouth, nausea, constipation, insomnia

C

Disclosure

Vallydia sells its own cosmetic serums, and some ingredients graded here belong to the same categories as those products. Grades are drawn from the published evidence by the method we publish, and applied to our own ingredients on the same terms — our copper-peptide serum is graded no more kindly than the peptides it competes with. We disclose the interest so you can weigh it.

Trade names shown here (for example Matrixyl, Argireline, Syn-Ake) are the property of their respective owners and are used only to identify the ingredient under discussion. Their appearance implies no affiliation with, or endorsement by, the proprietor.

Evidence changes

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Identity

a synthetic small molecule that simultaneously blocks the reuptake transporters for dopamine (DAT), norepinephrine (NET), and serotonin (SERT) — raising all three monoamine neurotransmitters in the brain. It acts centrally (in the brain), a mechanism completely different from the GLP-1/amylin/incretin peptides that dominate this register. Investigated for obesity — though that's not where it started.

Mechanism (as proposed)

tesofensine blocks all three monoamine transporters — SERT (serotonin), NET (norepinephrine), and DAT (dopamine) — increasing synaptic levels of each. The weight effects come from combining these: serotonin prolongs hypothalamic satiety signaling (reducing intake — the same broad pathway older appetite drugs used, but here one of three); norepinephrine drives adrenergic activation that raises energy expenditure; and dopamine modulates reward/food-craving circuitry (a stimulatory dopaminergic response in the nucleus accumbens and prefrontal cortex has been observed). So tesofensine attacks obesity from both the intake and the expenditure side — pharmacologically elegant, but also why it looks like an antidepressant-class mechanism (SSRIs/SNRIs/DRIs combined) rather than a metabolic-hormone drug, and why the cardiovascular and CNS side-effect profile needs respect. Its human weight-loss mechanism is officially "unresolved," an honest scientific footnote.

Chemical identifiers

Cross-reference identifiers for the authoritative external databases — not a recipe, and nothing about how to use it.

PubChem CID11370864

InChIKeyVCVWXKKWDOJNIT-ZOMKSWQUSA-N

SMILESCCOC[C@H]1[C@H]2CC[C@H](N2C)C[C@@H]1C3=CC(=C(C=C3)Cl)Cl

UNIIBLH9UKX9V1

ChEMBLCHEMBL3989690

DrugBankDB06156

via PubChem exact-name match (Tesofensine) · high confidence

Sources — 4 cited

01Astrup A, et al. Effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trial. Lancet 2008;372:1906-1913 (Phase 2; ~2× era's drugs; HR +~7 bpm).

02Astrup A, Meier DH, Mikkelsen BO, Villumsen JS. Weight loss produced by tesofensine in patients with Parkinson's or Alzheimer's disease. Obesity 2008;16:1363-1369 (the pooled neurology analysis that revealed dose-dependent weight loss).

03Sjödin A, et al. The effect of the triple monoamine reuptake inhibitor tesofensine on energy metabolism and appetite… Int J Obes 2010 (↑energy expenditure + ↓appetite; mechanism "unresolved").

04NeuroSearch/Saniona development history (NS-2330 → obesity pivot → Phase 3; tesofensine/metoprolol combination for heart-rate management). (Not an approved obesity drug in major markets; small molecule, not a peptide.)

Updated 2026-07-13 (status: Phase 2/3 investigational; the open questions are Phase 3 confirmation and cardiovascular safety — and whether any CNS-monoamine drug can compete with the incretin era)

Grades reflect the published evidence, not our interest. No dosing, reconstitution, or administration is published for research compounds — that restraint is deliberate.

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