Tesofensine

Key points

• Tesofensine is a once daily tablet, not a peptide, that blocks the reuptake of noradrenaline, dopamine and serotonin.
• It was first tested for Parkinson's and Alzheimer's disease, where weight loss was noticed as a side effect.
• A mid stage trial showed meaningful weight loss, but no large final stage obesity trial has been completed.
• It has no UK marketing authorisation, and it is banned in sport.

Quick facts

What it is

Triple monoamine reuptake inhibitor, oral (not a peptide)

Studied for

Weight loss and obesity

UK status

Not a licensed medicine; no UK marketing authorisation

Human evidence

One mid stage trial; no large obesity trial

In sport

On the WADA Prohibited List

How it works

By keeping more noradrenaline, dopamine and serotonin active in the brain, tesofensine mainly reduces appetite and increases the feeling of fullness. Its effect on how much energy the body burns is small. These are the same brain chemicals targeted by some other appetite medicines, which is also why it can affect mood, sleep, heart rate and blood pressure.

What the evidence shows

The main evidence is a mid stage trial in people with obesity, which reported around 9 percent weight loss over about six months, more than placebo. Beyond that there are the earlier studies in brain conditions. No large final stage obesity trial has been completed or published, and it has not been compared with modern medicines such as semaglutide.

What it does not settle

• There is no completed large obesity trial.
• Long term safety, and whether weight stays off, are unknown.
• Questions have been raised about how fully side effects were reported.

Side effects

Common

• Dry mouth, nausea and constipation.
• A faster heart rate, and trouble sleeping, anxiety or other mood effects.

Less common but serious

• It can raise heart rate and, at higher doses, blood pressure, so it is a concern for people with heart or blood pressure conditions.
• Its very long action means effects can continue after stopping, and products bought online are of unverified dose and quality.

Report any suspected side effect through the MHRA Yellow Card scheme.

UK legal status and access

Tesofensine has no UK marketing authorisation, so it is not a licensed medicine and is not offered by registered clinics or pharmacies. Products sold online as research chemicals or supplements have had no check on their safety, dose or purity.

Common questions