Underwriting in the age of weight-loss medication

Today, weight-loss drugs are headline news – and a growing number of customers  are self-administering the jabs.

“Just 12 months ago, we saw these cases only occasionally,” says Fraser Ballantine, underwriting quality and risk manager at Zurich. “Now, they’re coming through far more frequently – and advisers are starting to want clarity on how the use of these drugs might affect their customers’ protection journey.”

Use of medicated weight-loss treatments has surged in recent months. According to IQVIA, a global health data and analytics company, there were around 1.5 million users in the UK as of March 2025¹.

“While some people still turn to traditional methods to lose weight, such as healthy eating and increasing exercise, the flood of social media posts showing dramatic body transformations has fuelled growing interest in weight-loss drugs,” says Ballantine.

For insurers, the health impact of obesity – and the benefits of tackling it – go well beyond appearance.

“Obesity is a major risk factor not only for type 2 diabetes, but also for heart attacks, strokes, certain obesity-related cancers and even dementia, so successful weight loss can have far-reaching health benefits,” Ballantine adds.

Known medically as GLP-1 receptor agonists, these drugs were originally developed to help diabetic patients control blood sugar. But clinical trials showing double-digit weight reductions quickly shifted the spotlight, with demand for their use in weight management far exceeding the original remit.

While NHS guidance still limits prescriptions to patients meeting strict obesity criteria, private access has surged.

“People are buying them from reputable high-street and online providers” says Ballantine. “The reality is that many customers are using these drugs without necessarily meeting the strict NHS eligibility thresholds.”

This shift means insurers must now adapt to disclosures that blur the line between medical treatment and lifestyle – and advisers need clarity on how they are assessed.

A positive stance

In clinical trials, GLP-1 drugs have helped patients lose 15-21% of their body weight. In practice, the results can be more modest.

A survey presented at the 2025 annual scientific meeting of the American Society for Metabolic and Bariatric Surgery in June showed an average weight loss of 4.7% for patients who took GLP-1 prescription medication for at least six months or 7% for those who took it for a year, compared to total weight loss of 24% for those who underwent bariatric surgery².

Nevertheless, insurers’ approach so far is largely constructive. “Generally speaking, we see the use of weight-loss medications as a positive,” Ballantine explains. “If someone is obese and they’re losing weight, the long-term health benefits are likely to outweigh the risks.”

Zurich has not yet added dedicated questions about weight-loss drugs to its applications, though this is under consideration. For now, disclosures are expected through existing questions.

The most relevant of these asks: ‘In the last two years have you had medication or treatment that lasted more than four weeks or have you been treated in hospital as an inpatient?’

Ballantine says: “If someone is taking weight loss medication, we’d expect to see it disclosed under this question.

“If a customer has chosen to use GLP-1 to improve other conditions such as high blood pressure, we’d also expect the high blood pressure to be disclosed on the application.”

Assessing risks

Mechanistically, GLP-1 drugs mimic hormones that regulate appetite and digestion. They slow stomach emptying and increase satiety, meaning users feel full more quickly and for longer.

“In simple terms, they reduce appetite,” Ballantine explains. “So far, the evidence shows that almost everyone loses weight while taking them. The challenge is what happens next – do they keep it off?”

NHS England restricts access to those with the greatest clinical need – usually a BMI of 40 or above (adjusted for ethnicity), alongside obesity-related conditions such as type 2 diabetes, high blood pressure, high cholesterol, cardiovascular disease or sleep apnoea³.

Treatment via the NHS also brings access to dieticians, psychologists and other weight-management specialists. So far, the majority of Zurich applicants have obtained the medication privately.

That distinction matters. Weight-loss injections are most effective when combined with structured support such as diet, exercise and psychological input. Without those elements, weight regain is common once treatment stops.

Cost is another factor that could affect sustainability. While these drugs are currently relatively affordable, price hikes can disrupt treatment. For instance, Eli Lilly, the manufacturer of Mounjaro, recently announced an increase of up to 170% – from £122 to £330 per month for the highest dose⁴. Such an increase could cause customers to discontinue treatment mid-course, increasing the likelihood of weight regain.

“That’s where our concern lies,” says Ballantine. “If people buy the drugs online without proper support or they can’t afford to continue taking them, there’s a higher chance that the weight will come back.”

Studies suggest many users regain at least half the weight once medication ends. As a result, underwriters typically assume some reversal when assessing BMI.

“We’ll usually add back around 50% of any weight lost in the past 12 months when we calculate BMI,” says Ballantine. “It’s a pragmatic approach, but it reflects what the evidence shows.”

For now, most applications involving weight-loss drugs are assessed manually, allowing underwriters to assess individual circumstances.

Certain cases require closer scrutiny, such as applicants continuing treatment with a BMI below 25, or those with a history of eating disorders, gastric surgery or significant mental health issues. “Those are the cases where we’d probably ask for medical evidence,” Ballantine adds.

Application implications

Because GLP-1 drugs are still relatively new in obesity treatment, long-term data is limited. Most safety evidence comes from their use in diabetes. Known risks include rare cases of pancreatitis and gastrointestinal issues, as well as loss of muscle mass and bone density leading to osteoporosis.

“There is a class action lawsuit in the US claiming side effects weren’t fully disclosed,” Ballantine notes. “It’s something we’re watching, but for now the evidence suggests the benefits outweigh the risks – especially for those at higher risk of diabetes or cardiovascular disease.”

For advisers and customers, the picture is largely positive. Sustained weight loss can mean not only application acceptance, but also lower premiums.

BMI remains the key rating factor, with loadings generally starting around 30.

“Someone with a BMI of 42 might previously have been declined,” Ballantine explains. “If they’ve brought that down to 32 with medication, suddenly they’re in the range where we can offer terms. That can transform adviser conversations and customer outcomes.”

For those able to maintain a reduced weight – showing their relationship with food has changed – the outlook improves further.

“If someone has stopped the medication and held a healthy BMI for at least six months, we’re more comfortable treating their new weight as stable,” he adds.

Key takeaways

For advisers, the growing prevalence of weight-management drugs means more customer conversations – and the need to handle them sensitively.

“For many people, this will be the first approach that’s ever worked for weight loss,” says Ballantine. “Weight can be a sensitive topic – customers may find it difficult to discuss, or they may be proud of what they’ve achieved. It’s important to have that conversation in an understanding and supportive way.”

Advisers should also reassure customers that insurers are engaging constructively with the trend – and outcomes are often more favourable than before.

“It’s not a barrier to cover,” Ballantine explains. “In many cases, it improves the customer’s insurability. What matters is sustainability – whether the weight loss can be maintained over time.”

When clients disclose use of these medications, advisers should capture key details:

• When and why the medication was started
• How much weight has been lost
• Whether treatment is ongoing
• Any side effects or complications

“The more accurate and complete the disclosure, the smoother the underwriting process will be,” says Ballantine.

The rise of GLP-1 weight-loss drugs is reshaping protection conversations, offering new opportunities for advisers to support clients’ health journeys while improving insurability.

“Ultimately, these drugs are here to stay,” Ballantine concludes. “We’re learning more all the time, but the direction of travel is clear: if they help customers reduce obesity and related health risks, that’s good news for insurers, advisers and customers alike.”

¹https://www.thepharmacist.co.uk/clinical/cardiovascular/around-1-5-million-uk-citizens-used-weight-loss-jabs-in-march-2025/
²https://asmbs.org/news_releases/head-to-head-study-shows-bariatric-surgery-superior-to-glp-1-drugs-for-weight-loss/
³https://www.england.nhs.uk/ourwork/prevention/obesity/medicines-for-obesity/weight-management-injections/
⁴https://www.bbc.com/news/articles/c5ylppp2vj9o