Experts have pinpointed exactly why slimming jabs may trigger one bizarre side effect: a drop in sex drive. 

Once aimed at diabetes patients, drugs like Mounjaro and Wegovy are now famous for bringing about rapid weight loss by reducing appetite.

The side effects of these injections have been extensively discussed, including symptoms like nausea and constipation, with severe cases leading to potentially life-threatening organ damage.

Now, doctors have warned that the medication may also have another awkward and unsexy consequence—patient’s libidos to plummet. 

But a lack of intimacy may not be triggered by unpleasant side effects like constipation, bloating or crushing fatigue, they say.

An increasing number of experts suggest that the medication could reduce libido due to its effect on certain brain chemicals.

The injections promote weight loss by replicating the actions of a hormone released in the gut post-meal—GLP-1; research has demonstrated they also impact dopamine release.

Dr. Ryan Sultan, an assistant professor of clinical psychiatry at Columbia University, informed Medscape: ‘Sex is also driven by motivation and reward, and there is significant overlap in the neuronal networks responsible for food and sexual drives.

Now, doctors have warned that the medication may also have another awkward and unsexy consequence—patient’s libidos to plummet

‘When we take GLP-1s, we are essentially dampening the internal processes that drive us to address our evolutionary needs. 

‘By inhibiting the pathways that drive us towards food acquisition, we are subsequently affecting the overlapping systems that drive us to have sex.’

Dr. Bronwyn Holmes, a physician and hormone expert at US weight loss clinic Eden, commented: ‘These drugs are believed to suppress dopamine-driven reward signals, which assist in reducing food cravings and other compulsive behaviors.

This indirectly influences mood and motivation, which is beneficial for weight loss but might affect other activities driven by reward, such as intimacy or alcohol consumption.

‘In most cases, libido or mood-related side effects are reversible after stopping the medication. 

‘However, the timeline and completeness of reversal vary based on the individual and the presence of other contributing factors.’

One British study published last year in QJM: An International Journal of Medicine found new patients on the drug may experience cognitive changes in their decision-making, partly from the calorie deficit the drug induces, as well as the effects of GLP-1 on brain function.

‘This isn’t as far-fetched as it might sound,’ the researchers said.

The researchers found that females between the ages of 20 and 59 who had sex less than once a week were at a 70 per cent increased risk of death within five years 

There are, however, no large-scale studies to suggest how common these changes are, or whether they affect certain groups of people more than others.

Dr Kent Berridge, a professor of psychology and neuroscience at the University of Michigan, previously told the Daily Mail that having sex with a partner, thinking of having sex with them and seeing them would normally trigger sexual desire, ‘just like drug use triggers desire for drugs’.

‘But if you’re suppressing [dopamine activation] a little bit and cutting down those mountain peaks, sexual desire is a natural peak, so that would be plausible.

‘It may be partly acting right on the nucleus accumbens [the brain structure known for its role in pleasure, reward and addiction], because there are receptors there.’

At least half a million NHS patients and some 15 million patients in the US are now thought to be using weight-loss jabs, which can help patients lose up to 20 per cent of their body weight in just a few months.

And the numbers using them privately are even higher.

The health service currently prescribes Wegovy to around 35,000 patients at specialist weight management clinics.

Mounjaro, meanwhile, has been available in similar clinics since March and as of this month, GPs are also able to prescribe it.

The drug warning also comes amid concern about a global sex crisis—or rather, lack of sex crisis.

One recent survey revealed more than a quarter (27 per cent) of Britons are now having less sex than they used to, with one in six admitting they haven’t got frisky the entire year.

According to a Royal College of Occupational Therapists poll of 2,000 adults last year, men and women typically only have sex 46 times a year — once every eight days.

But some have far less frequent amorous activity, with a tenth reported having sex less than once a year.

Sex and intimacy have been linked to several health benefits, including improving the condition of your heart, reducing stress and even boosting mental health.