Two major warnings issued for weight loss jabs as experts reveal worrying side effects

Two major warnings have been issued over the use of weight loss jabs as experts have revealed the worrying side effects attached to the medicine.

Australia's medicines regulator The Therapeutic Goods Administration (TGA) has issued new recommendations for patients using GLP-1 receptor agonists, which include Ozempic, Wegovy, Saxenda, Trulicity and Mounjaro.

While these drugs can be an important tool for people struggling to manage their weight, they do also come with a number of side effects.

Now, it's important to note that Novo Nordisk, the manufacturer behind Ozempic and Wegovy, has highlighted that Ozempic is primarily meant for adults with type 2 diabetes rather than those looking to lose weight, while Wegovy and Mounjaro (the brand name for tirzepatide from Eli Lilly) can be prescribed by the NHS for weight loss.

Mental health concerns

The link between weight loss drugs and mental health is being examined (Peter Dazeley / Contributor / Getty Images)

The TGA is recommending that doctors should watch out for 'the emergence or worsening of depression, suicidal thoughts or behaviours, and/or any unusual changes in mood or behaviour' in patients taking GLP-1 drugs.

The fresh warnings come after a 2024 analysis of the World Health Organisation's adverse reaction database, which revealed that reports of suicidal ideation associated with semaglutide exceeded anticipated levels compared to other diabetes treatments.

Australia's database recorded 72 reports for suicidal ideation, six reports for depressional suicide, four reports of suicide attempt, two reports of completed suicide and one report of self-injurious ideation up to September.

With over two million semaglutide prescriptions subsidised in 2023-24, plus many more unsubsidized users, advisors noted the complicated relationship between mental illness and chronic endocrine conditions (related to glands and organs that produce hormones) but found insufficient evidence to prove causation.

Dr Terri-Lynne South, the chair of the Royal Australian College of General Practitioners’ specific interest group for obesity management, said: "We do think there might be a subgroup of patients who may be more vulnerable to a worsening of their mental health.

"At the moment, that seems to be people who might already have a past or current history of depression or anxiety or are on an antidepressant type medication."

She also noted that research on bariatric surgery patients shows rapid weight loss can be a 'real triggering event from a mental health point of view'.

Contraceptive concerns

(Matthew Horwood / Contributor / Getty Images)

The regulator also addressed contraceptive concerns with Mounjaro specifically.

After being unable to dismiss a possible link between the medication and reduced oral contraceptive effectiveness, the TGA now advises patients to either switch to non-oral contraception or supplement with barrier methods for four weeks after starting Mounjaro and following each dosage increase.

South explained that Mounjaro slows gastric emptying, potentially affecting how the body absorbs oral contraceptives. The regulator emphasises that no GLP-1 receptor agonist should be used during pregnancy.

"What that means is [the drug] delays the food and everything else that you eat actually coming through the digestive system, and therefore having an impact on the absorption of the oral contraceptive pill, and therefore possibly the effectiveness of the oral contraceptive pill," she said.

A Novo Nordisk Oceania spokesperson told Tyla: "Patient safety is a top priority for Novo Nordisk, and we take all reports about adverse events from the use of our medicines very seriously

"Semaglutide has been studied in robust clinical development programs, including SUSTAIN, PIONEER, STEP, SELECT, STRIDE, SOUL, FLOW and ESSENCE, with more than 54,000 participants having used semaglutide (in trials).

"Post marketing, semaglutide has resulted in more than 37 million patient years (meaning the total combined time all patients in a study are observed, often used to measure risk or outcomes over time).

"Considering the totality of evidence from clinical trials, post-marketing reports and observational studies, Novo Nordisk believes that the benefit-risk profile of semaglutide remains favourable.

"We remain committed to patient safety and transparency by maintaining up-to-date safety information and collaborating closely with health authorities and regulatory bodies worldwide."

Tyla has also contacted Eli Lilly for comment.

If you're experiencing distressing thoughts and feelings, the Campaign Against Living Miserably (CALM) is there to support you. They're open from 5pm–midnight, 365 days a year. Their national number is 0800 58 58 58 and they also have a webchat service if you're not comfortable talking on the phone.