The United Kingdom will study whether the use of weight loss drugs could get people back to work.

UK Health Minister Wes Streeting announced last month that US drug manufacturer Eli Lilly will begin a five-year trial in Greater Manchester to test if the company’s weight loss drug could curb the UK’s unemployment crisis.

The announcement came a day after UK Prime Minister Keir Starmer hosted a summit to encourage investment in the UK, which was attended by Eli Lilly.

But what have weight-loss drugs got to do with unemployment and how will this work?

What is the weight loss drug experiment in the UK?

On October 14, Starmer hosted a summit to encourage investment in the UK. Attendees included David Ricks, the chair of US pharmaceutical giant Eli Lilly, who announced a 279-million-pound ($365.4m) investment in the UK. Further details about how this money would be spent have not been revealed.

Eli Lilly is the manufacturer of weight loss drugs Mounjaro and Zepbound.

About 3,000 residents of Greater Manchester will take part in the study that aims to observe the long-term effects of weight loss drugs. Further details of the study are not known yet.

According to the 2021 official health survey, about 25.9 percent of adults in the UK are obese, while another 37.9 percent are overweight. According to the World Health Organisation (WHO), a person with a body mass index (BMI) of more than 25 is considered overweight, and those with BMI of more than 30 are considered obese.

Obesity-related health issues cost the UK’s National Health Service (NHS) 11 billion pounds ($14bn) each year, UK Health Secretary Streeting said while announcing the Eli Lily study.

UK Chancellor of the Exchequer Rachel Reeves and Health Secretary Wes Streeting speak with members of staff at St George’s Hospital on October 28, 2024 in London, UK [Leon Neal/Pool via Reuters]

What is the unemployment rate in the UK?

The unemployment rate in the UK was 4 percent of all those aged over 16 who are actively seeking employment, as of August 2024, according to the UK parliament’s research archive, the House of Commons Library.

The unemployment rate has fallen over the last year, and 75 percent of people aged 16-64 were employed.

What have weight loss drugs got to do with unemployment?

There is also economic inactivity in the UK, which means people are not in jobs and are not actively searching for jobs. According to a UK Labour Market Statistics report published on October 15, there were 9.26 million economically inactive people aged 16 to 64 in the UK. The term “economically inactive” encompasses both those people aged over 16 who are actively seeking employment, and those who who are not seeking work or are unable to work. The latter includes students, retired people and those caring for others.

Between June to August 2024, 30 percent of people said they were economically inactive due to a long-term illness and 27 percent said it was because they were students. These numbers are around the same level they were the previous year.

The UK Labour Market Statistics report does not elaborate on whether obesity or diabetes were specific health issues that influenced economic inactivity.

The chief executive of unemployment charity Yes Manchester, Adam Green, told the BBC that obesity was not the main reason why some people were struggling to get employed, however.

“It’s a complicated area and very much observational data only,” Philip Newland-Jones, a consultant pharmacist in diabetes and endocrinology at University Hospital Southampton in the UK, told Al Jazeera.

“Studies show that those that are unemployed are more likely to be obese, and the longer you are unemployed the more likely you are to be obese. There is no strict causation attached to this and no absolute strong evidence that obesity is what has led to unemployment, or that it continues to hamper employment,” Newland-Jones said.

He added that he is unaware of any study that suggests that giving people weight loss drugs results in getting people back to work. “I presume this is the data that the UK government will look to generate with these trials in the hope that the cost of the medicines will be paid for by increased productivity, or increased GDP,” he said.

How do weight-loss drugs work?

Weight loss drugs essentially work by suppressing the appetite.

Denmark-based Novo Nordisk’s Wegovy and Ozempic are semiglutide injections while Mounjaro and Eli Lilly’s Zepbound are tirzepatide injections. These are the four main weight-loss drugs used around the world. Ozempic is mainly used in the US, Japan, the European Union, Canada and Australia; Mounjaro is prescribed in the US, UK, EU and Australia. They are prescription-only drugs, but can also be bought on the grey market on the internet.

Both semiglutides and tirzepatides suppress the appetite by mimicking a hormone called glucagon-like peptide-1 (GLP-1).

Both types of drugs are self-administered once a week from a pre-filled pen. They can be injected into the upper arm, thigh or stomach.

GLP-1 is an intestinal hormone, which the body naturally releases after eating food. The job of GLP-1 is to send a signal to the brain that the stomach is full.

Tirzepatides work with a second hormone in addition to GLP-1 called the gastric inhibitory polypeptide (GIP). This is naturally released by cells in the gut and is responsible for regulating blood glucose.

How much weight can you lose taking these drugs?

“People who used the largest dose of Mounjaro – 15 milligrams per week – lost as much as 21 percent of their body weight,” Dr Cecilia Low Wang, an expert on endocrinology, diabetes and metabolism was quoted saying in an article published by the United States-based University of Colorado healthcare system, UCHealth.

Dr Wang also quoted Food and Drug Administration (FDA) officials, saying people on tirzepatides like Mounjaro have lost more weight on average than those on semiglutides.

The FDA approved Mounjaro and Ozempic for use by patients with diabetes in 2022 and 2017, respectively, but has not yet done so specifically for weight loss. Wegovy and Zepbound were approved for weight loss in 2021 and 2023, respectively.

Is weight loss permanent if you take these drugs?

No. Quoted in the UCHealth article, Dr Low Wang explained: “Just like Ozempic and Wegovy, if you lose weight with Mounjaro, you likely will need to keep taking the medication forever to keep the weight off.”

US-based Fortune magazine quoted several doctors in July this year who said clinical trials had shown that when people stop taking weight-loss drugs, they gain back all the weight they lost within about a year.

Do weight loss drugs have side effects?

Yes, possibly.

For Mounjaro, common side effects include nausea, diarrhoea, decreased appetite, vomiting, constipation, indigestion and stomach pain, as listed on the drug’s website.

The website adds that for people with kidney problems, diarrhoea and vomiting may cause dehydration which can exacerbate the kidney problems. It stresses the importance of staying hydrated.

There is an additional set of safety warnings on the website. The safety warning pop-up says “Mounjaro may cause tumours in the thyroid, including thyroid cancer,” cautioning users of the medication to watch out for possible symptoms.

Additionally, serious side effects can include the inflammation of the pancreas – or pancreatitis – low blood sugar, serious allergic reactions, severe stomach problems, changes in vision and issues with the gallbladder.