{"id":271842,"date":"2026-02-07T05:15:21","date_gmt":"2026-02-07T05:15:21","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/271842\/"},"modified":"2026-02-07T05:15:21","modified_gmt":"2026-02-07T05:15:21","slug":"everything-you-need-to-know-about-glp-1s-for-weight-loss","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/271842\/","title":{"rendered":"Everything you need to know about GLP-1s for weight loss"},"content":{"rendered":"

Glucagon-like peptide-1 (GLP-1) receptor agonists were touted as \u201cbreakthrough\u201d drugs<\/a>\u00a0in 2023 \u2014 and their popularity has soared since.\u00a0<\/p>\n

Around 2.5 million people each month<\/a>\u00a0accessed GLP-1s privately at the end of 2025, according to James Kingsland, chair of the\u00a0Digital Clinical Excellence (DiCE) network<\/a>\u00a0of primary care digital health providers. Data also show that more than 400,000 items of tirzepatide and semaglutide were dispensed on the NHS in October 2025\u200b1\u200b.\u00a0<\/p>\n

An estimated 3.3 million UK adults are expected to use weight-loss injections in 2026, according to a\u00a0YouGov poll commissioned by the National Pharmacy Association<\/a>. This article collates the latest evidence supporting GLP-1 use for weight loss, including trials in which they are being evaluated, while signposting to relevant articles from\u00a0The Pharmaceutical Journal\u00a0for detailed information related to their safe and effective use. It will be updated on a regular basis.<\/p>\n

What are GLP-1s?<\/p>\n

GLP-1 receptor agonists work by targeting GLP-1 receptors: increasing insulin, decreasing glucagon and delaying gastric emptying\u200b2\u200b.<\/p>\n

Originally developed for use in type 2 diabetes mellitus,\u00a0GLP-1s are increasingly being licensed for weight-loss<\/a>\u00a0and other cardiometabolic applications.<\/p>\n

Some newer drugs combine GLP-1 receptor agonists with other metabolic targets or additional mechanisms to achieve more effective weight loss. For example, tirzepatide (Mounjaro; Eli Lilly) combines a GLP-1 receptor agonist with a glucose-dependent insulinotropic polypeptide (GIP) receptor agonist.<\/p>\n

Figure 1 outlines the GLP-1 receptor agonists that can be prescribed in Great Britain for weight loss\u200b3\u201313\u200b.<\/p>\n

Figure 1: Which GLP-1s can be prescribed in Great Britain for weight loss?<\/p>\n

Two types of GLP-1 drug are no longer in use in the UK: exenatide (Bydureon BCise;\u00a0
AstraZeneca UK) 2mg\/0.85mL prolonged-release suspension for injection pre-filled pen was discontinued<\/a>\u00a0in October 2025, and lixisenatide (Lyxumia; Sanofi) 20 micrograms\/0.2mL solution for injection 3mL pre-filled disposable devices were\u00a0discontinued<\/a>\u00a0in 2023. Dulaglutide is currently only licensed for people with diabetes, as Trulicity (Eli Lilly)\u200b14\u200b.<\/p>\n

Other weight-loss drugs are currently in development or regulatory approval stages, including:<\/p>\n

Oral Wegovy, a once-daily 25mg semaglutide pill that was approved by the US Food and Drug Administration (FDA) in December 2025. In the \u2018OASIS 4\u2019 clinical trial, participants taking oral Wegovy recorded a mean body weight reduction of 13.6% after 71 weeks, compared with a 2.2% loss in the placebo group\u200b15\u200b;Once-daily GLP-1 pill\u00a0orforglipron (Eli Lilly)<\/a>, which, when taken alongside a healthy diet and exercise, resulted in a 7.5% weight loss over 72 weeks on the 6mg dose, 8.4% loss with 12mg of orforglipron, and 11.2% loss with 36mg of orforglipron, compared with a 2.1% loss with placebo\u200b16\u200b. A NICE committee is due to meet in July 2026\u00a0to discuss NHS use in England and Wales;Retatrutide (Eli Lilly) an injectable triagonist currently in phase III clinical trials that\u00a0adds a glucagon receptor agonist to its mechanism of action<\/a>, promising an even greater impact on weight loss\u200b17\u200b.What are the known side effects and safety concerns?<\/p>\n

Gastrointestinal side effects make up around half of the side effects reported to the MHRA via the Yellow Card Scheme for tirzepatide, semaglutide and liraglutide between 2020 and 2025 (43,475 out of 78,171 side effects; see Figure 2)\u200b18\u200b.<\/p>\n

Figure 2: Around half of GLP-1 side effects are gastrointestinal<\/p>\n

GLP-1s have previously been suggested to be linked to self-harm and suicidal thoughts, but the MHRA concluded in September 2024<\/a>\u00a0that the available data do not support a causal association between GLP-1s and\u00a0depression<\/a>,\u00a0suicidal ideation and suicide<\/a>, following a\u00a0review by the European Medicines Agency\u2019s pharmacovigilance risk assessment committee<\/a>\u200b19\u200b.<\/p>\n

Can GLP-1s cause pancreatitis?<\/p>\n

While the majority of side effects so far reported to the MHRA for tirzepatide and semaglutide are non-serious\u200b18\u200b, there are growing warnings about serious conditions, such as\u00a0acute pancreatitis<\/a>,\u00a0associated with GLP-1 use, although studies currently remain inconclusive\u200b20\u200b.\u00a0<\/p>\n

On 29 January 2026, the MHRA updated\u00a0product information\u00a0for GLP-1s and issued a\u00a0drug safety alert<\/a>\u00a0to highlight that acute pancreatitis is a\u00a0known but\u00a0infrequent\u00a0side effect that can be fatal, stressing that patients and clinicians should be alert to initial symptoms<\/a>, such as\u00a0severe, persistent\u00a0stomach\u00a0pain that may radiate to the back and may be accompanied by nausea and vomiting\u200b21\u200b.<\/p>\n

Between 2019 and 2025, 256 cases of acute and chronic pancreatitis associated with semaglutide use were reported to the MHRA\u2019s Yellow Card scheme, 4 of which had a fatal outcome\u200b22\u200b. Data also show that there were 8,887 cases of acute and chronic pancreatitis following tirzapatide use reported between 2023 and 2025, 13 of which had a fatal outcome\u200b23\u200b.\u00a0<\/p>\n

For liraglutide, there were 137 reports of\u00a0\u00a0acute and chronic pancreatitis made to the MHRA\u2019s Yellow Card scheme between 2020 and 2025, one of which had a fatal outcome\u200b24\u200b. Yellow Card reports for liraglutide more generally record a higher rate of serious adverse effects, but a lower total of reports overall, which may reflect less widespread use of the drug\u200b24\u200b.<\/p>\n

Acute\u00a0pancreatitis<\/a>\u00a0can be caused by gallstones or bile duct stones when they block the tubes leading from the pancreas to the stomach, which can be caused by rapid weight loss\u200b25\u200b. To investigate further,\u00a0the MHRA and UK Biobank<\/a>\u00a0are working together to understand if there is a genetic link between GLP-1s and drug-induced acute pancreatitis,\u00a0similar to that with immunosuppressant drug thiopurine<\/a>.<\/p>\n

Does GLP-1 use cause muscle loss and reduced bone density?<\/p>\n

GLP-1s are thought to cause\u00a0higher muscle loss\u00a0(25\u201339%) than non-pharmacological methods of weight loss, such as diet and exercise (10-30%)\u200b26\u200b.<\/p>\n

Excess body weight puts stress on the joints, increasing risk of fractures, but weight loss from calorie restriction is associated with reductions in bone mineral density (BMD) with increased bone turnover; however, emerging evidence suggests that GLP-1s may pharmacologically mitigate against the negative bone health impacts of weight loss\u200b27\u200b.<\/p>\n

Can GLP-1s affect the eyes?<\/p>\n

Analysis of GLP-1 side effects reported to the US FDA suggest an increased reporting of various eye disorders across both patients with diabetes and those without; however, a 2025 study concluded that further research is required to support these findings and confirm a biological causation\u200b28\u200b.<\/p>\n

In patients with diabetes, GLP-1 RAs have been linked to an\u00a0increased risk of age-related macular degeneration<\/a>, although the overall risk is still low.\u00a0But, in patients without diabetes, preliminary studies suggest GLP-1 use could be associated with lower risk, although more research is needed\u200b29,30\u200b.<\/p>\n

According to a review conducted by the European Medicine\u2019s Agency safety committee in 2025,\u00a0non-arteritic anterior ischemic optic neuropathy\u00a0is a very rare side effect of semaglutide<\/a>\u00a0that could affect 1 in 10,000 people\u200b31\u200b.<\/p>\n

Can GLP-1s be used in pregnancy?<\/p>\n

There are\u00a0not enough data to determine the impact of GLP-1 medicines on human pregnancies<\/a>\u00a0but, in\u00a0some animal studies<\/a>, GLP-1 medicines were found to be harmful to the unborn foetus\u200b32\u200b. Therefore, GLP-1s should not be used in pregnancy.\u00a0<\/p>\n

The\u00a0MHRA advises<\/a>\u00a0patients on all GLP-1s to use contraception while taking GLP-1 medicines (including an additional barrier method for patients starting or increasing tirzepatide who are using oral contraception), as well as for a defined \u201cwash-out\u201d period afterwards before trying to get pregnant (see Figure 3). GLP-1 drugs should not be used while breastfeeding\u200b33\u200b.<\/p>\n

Figure 3: How many months should GLP-1s be stopped before a pregnancy?What is current best practice when prescribing GLP-1s for weight loss?Switching GLP-1s<\/p>\n

Patients or clinicians might consider switching between weight-loss medications; for example, owing to adverse effects, patient preference, cost pressures or formulary decisions. There is little clinical guidance on this, so pharmacists must prioritise patient safety and, since there is no validated dose equivalence,\u00a0the safest approach is to start the new medication its lowest available dose then titrate gradually per standard schedule<\/a>.<\/p>\n

Stopping GLP-1s<\/p>\n

A 2025 study found that people who used weight-loss medication regained weight more rapidly, with an average monthly weight regain of 0.4kg compared with 0.1kg in those who followed behavioural weight management programmes\u200b34\u200b.\u00a0<\/p>\n

John Wilding, professor of medicine in the Department of Cardiovascular and Metabolic Medicine at the University of Liverpool,\u00a0said<\/a>\u00a0this was unsurprising, adding: \u201cObesity is a chronic disease that usually relapses when treatment is stopped.\u201d<\/p>\n

Tricia Tan, professor of metabolic medicine, diabetes and endocrinology at Imperial College London\/Imperial College Healthcare NHS Trust, said: \u201cThere is increasing evidence that structured exercise is important to prevent weight regain after cessation of weight-loss drugs,\u201d but noted that this was not discussed in the study.\u00a0<\/p>\n

Wraparound support in weight loss<\/p>\n

Experts have stressed the \u201cmulti-factorial\u201d causes of obesity and therefore the need for a multi-faceted approach, considering other factors like lifestyle, trauma and psychological support\u200b35\u200b.<\/p>\n

GLP-1s are only licensed for weight loss as an adjunct to a calorie-controlled diet and exercise, and should be offered as part of a holistic weight management service.<\/p>\n

In August 2025, the\u00a0National Institute for Health and Care Excellence\u00a0quality standard for overweight and obesity management<\/a>\u00a0was\u00a0updated to add<\/a>\u00a0that people who are stopping weight-loss medicines should be given advice for maintaining changes and support for improving their health and wellbeing<\/a>.\u00a0<\/p>\n

Inappropriate access to GLP-1s<\/p>\n

Concerns have been raised about patients accessing GLP-1s inappropriately; for instance, when they do not meet BMI eligibility criteria. To combat this, the General Pharmaceutical Council<\/a>\u00a0set out guidance in September 2024\u00a0that said pharmacies must:<\/p>\n

Not rely solely on an online questionnaire<\/a>\u00a0but use two-way communication between patient and prescriber;Independently verify the person\u2019s weight, height and\/or body mass index; for example through a video consultation, in-person, from the person\u2019s clinical records or by contacting another healthcare provider, such as the person\u2019s GP;Consider the person\u2019s wellbeing given that eating disorders, body dysmorphia and mental health issues can play a part in the reason for requesting these medicines;Carry out or signpost to appropriate ongoing monitoring;Advise on side effects\u200b36\u200b.<\/p>\n

Weight-loss advertising is also a concern: some providers have fallen foul of\u00a0the\u00a0Association of the British Pharmaceutical Industry<\/a> regulations that ban the promotion of prescription drugs to patients, while social media and affiliate advertising increases the risk of prescription-only-medication promotion, including\u00a0to teenagers<\/a>\u00a0and other vulnerable people.<\/p>\n

The demand for weight-loss medication also makes it a\u00a0potential hotspot for criminal activity<\/a>, with unregulated suppliers acting illegally and sometimes selling drugs that do not contain medication as labelled and put patients\u2019 health at risk. In 2025,\u00a0the MHRA reported the seizure of more than 5,000 illegally traded GLP-1 pens<\/a>.\u00a0<\/p>\n

A recent survey commissioned by LloydsPharmacy\u202fOnline\u202fDoctor (survey size n=2,000, of those 285 are\u00a0current\u00a0and active users of GLP-1s for weight loss and 216 have recently stopped) found that 28% (n=140) of those surveyed who were using or had previously used\u00a0weight-loss injections had\u00a0knowingly\u00a0bought from unlicensed sellers,\u00a012% (n=60) think they may have done, and 20% (n=100) bought drugs that are unlicensed and untested for weight loss\u00a0in the UK\u200b37\u200b.<\/p>\n

One-third (32%, n=91)\u00a0of those currently taking weight-loss jabs said they had not taken their medication as prescribed. Of those, 28% (n=25) reported \u2018microdosing\u2019\u00a0(taking a smaller amount of medication than prescribed\u00a0to make it last longer), 23% (n=21) reported combining residual medication to create an\u00a0additional\u00a0\u201cgolden dose\u201d and 32% (n=29) reported taking a\u00a0short\u00a0break\u00a0from the medication to\u00a0save money or\u00a0make the most of\u00a0life events,\u00a0such as weddings or holidays.<\/p>\n

This off-label use is corroborated by the ongoing \u2018Smoking Toolkit Study\u2019, which added questions around weight-loss jabs to its representative monthly surveys in January to March 2025 (5,893\u00a0total respondents). These revealed that 12% of weight-loss drug users (20 out of 171) were using medication not licensed for this purpose.<\/p>\n

The researchers also found that weight-loss medication use was higher among women than men (4.0% versus 1.7%) and higher among those of middle age (4.2% of 45 and 55-year-olds compared to 1.2% of 18-year-olds and 1.5% of 75-year-olds). Prevalence was higher among those who reported moderate or severe psychological distress in the past month (3.7% vs. 2.4% among those reporting no\/low distress) and \u2014 while usage levels were similar across social grades \u2014 interest in using drugs to support weight loss in future was greater among more typically disadvantaged groups (among whom obesity is more prevalent)\u200b38\u200b.<\/p>\n

2.<\/p>\n

Liu Q. Mechanisms of action and therapeutic applications of GLP-1 and dual GIP\/GLP-1 receptor agonists. Front Endocrinol (Lausanne). 2024;15:1431292. doi:10.3389\/fendo.2024.1431292<\/a><\/p>\n

5.<\/p>\n

Effect of Liraglutide on Body Weight in Non-diabetic Obese Subjects or Overweight Subjects With Co-morbidities: SCALETM \u2013 Obesity and Pre-diabetes. ClinicalTrials.gov. January 2018. Accessed February 2026. https:\/\/clinicaltrials.gov\/study\/NCT01272219<\/a><\/p>\n

6.<\/p>\n

Pi-Sunyer X, Astrup A, Fujioka K, et al. A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management. N Engl J Med. 2015;373(1):11-22. doi:10.1056\/nejmoa1411892<\/a><\/p>\n

8.<\/p>\n

Research Study to Look at How Well Semaglutide is at Lowering Weight When Taken Together With an Intensive Lifestyle Program (STEP 3). ClinicalTrials.gov. November 2021. Accessed February 2026. https:\/\/clinicaltrials.gov\/study\/NCT03611582<\/a><\/p>\n

9.<\/p>\n

Wadden TA, Bailey TS, Billings LK, et al. Effect of Subcutaneous Semaglutide vs Placebo as an Adjunct to Intensive Behavioral Therapy on Body Weight in Adults With Overweight or Obesity. JAMA. 2021;325(14):1403. doi:10.1001\/jama.2021.1831<\/a><\/p>\n

11.<\/p>\n

Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205-216. doi:10.1056\/nejmoa2206038<\/a><\/p>\n

13.<\/p>\n

Wharton S, Freitas P, Hjelmes\u00e6th J, et al. Once-weekly semaglutide 7\u00b72 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial. The Lancet Diabetes & Endocrinology. 2025;13(11):949-963. doi:10.1016\/s2213-8587(25)00226-8<\/a><\/p>\n

15.<\/p>\n

Wharton S, Lingvay I, Bogdanski P, et al. Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity. N Engl J Med. 2025;393(11):1077-1087. doi:10.1056\/nejmoa2500969<\/a><\/p>\n

16.<\/p>\n

Wharton S, Aronne LJ, Stefanski A, et al. Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment. N Engl J Med. 2025;393(18):1796-1806. doi:10.1056\/nejmoa2511774<\/a><\/p>\n

19.<\/p>\n

Bezin J, B\u00e9nard-Laribi\u00e8re A, Hucteau E, et al. Suicide and suicide attempt in users of GLP-1 receptor agonists: a nationwide case-time-control study. eClinicalMedicine. 2025;80:103029. doi:10.1016\/j.eclinm.2024.103029<\/a><\/p>\n

20.<\/p>\n

Ayoub M, Chela H, Amin N, et al. Pancreatitis Risk Associated with GLP-1 Receptor Agonists, Considered as a Single Class, in a Comorbidity-Free Subgroup of Type 2 Diabetes Patients in the United States: A Propensity Score-Matched Analysis. JCM. 2025;14(3):944. doi:10.3390\/jcm14030944<\/a><\/p>\n

26.<\/p>\n

Prado CM, Phillips SM, Gonzalez MC, Heymsfield SB. Muscle matters: the effects of medically induced weight loss on skeletal muscle. The Lancet Diabetes & Endocrinology. 2024;12(11):785-787. doi:10.1016\/s2213-8587(24)00272-9<\/a><\/p>\n

27.<\/p>\n

Gatto A, Liu K, Milan N, Wong S. The Effects of GLP-1 Agonists on Musculoskeletal Health and Orthopedic Care. Curr Rev Musculoskelet Med. 2025;18(10):469-480. doi:10.1007\/s12178-025-09978-3<\/a><\/p>\n

28.<\/p>\n

Murray M, Schifano F, Chiappini S, Corkery JM, Guirguis A. Potential Eye Disorders in People With and Without Type 2 Diabetes Mellitus Exposed to GLP-1 Receptor Agonists: An Examination of the FAERS (FDA Adverse Event Reporting System) Database. American Journal of Ophthalmology. 2026;283:279-290. doi:10.1016\/j.ajo.2025.12.015<\/a><\/p>\n

29.<\/p>\n

Shor R, Mihalache A, Noori A, et al. Glucagon-Like Peptide-1 Receptor Agonists and Risk of Neovascular Age-Related Macular Degeneration. JAMA Ophthalmol. 2025;143(7):587. doi:10.1001\/jamaophthalmol.2025.1455<\/a><\/p>\n

30.<\/p>\n

Ahuja AS, Paredes AA III, Young BK. Glucagon-Like Peptide-1 Receptor Agonists and Age-Related Macular Degeneration. JAMA Ophthalmol. 2025;143(12):999. doi:10.1001\/jamaophthalmol.2025.3821<\/a><\/p>\n

32.<\/p>\n

Qiao L, Lu C, Zang T, Dzyuba B, Shao J. Maternal GLP-1 receptor activation inhibits fetal growth. American Journal of Physiology-Endocrinology and Metabolism. 2024;326(3):E268-E276. doi:10.1152\/ajpendo.00361.2023<\/a><\/p>\n

34.<\/p>\n

West S, Scragg J, Aveyard P, et al. Weight regain after cessation of medication for weight management: systematic review and meta-analysis. BMJ. 2026;392:e085304. doi:10.1136\/bmj-2025-085304<\/a><\/p>\n

35.<\/p>\n

Beyond GLP-1: the next wave of weight-loss medication innovation. Pharmaceutical Journal. Published online 2025. doi:10.1211\/pj.2025.1.375713<\/a><\/p>\n

37.<\/p>\n

Almost half of weight-loss drug users modify doses, finds survey. Pharmaceutical Journal. Published online 2026. doi:10.1211\/pj.2026.1.396657<\/a><\/p>\n

38.<\/p>\n

Jackson S, Brown J, Llewellyn C, Mytton O, Shahab L. Prevalence of use and interest in using glucagon-like peptide-1 receptor agonists for weight loss: a population study in Great Britain. BMC Med. 2026;24(1):1. doi:10.1186\/s12916-025-04528-7<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Glucagon-like peptide-1 (GLP-1) receptor agonists were touted as \u201cbreakthrough\u201d drugs\u00a0in 2023 \u2014 and their popularity has soared since.\u00a0…\n","protected":false},"author":2,"featured_media":271843,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[33],"tags":[134,524,111,139,69],"class_list":["post-271842","post","type-post","status-publish","format-standard","has-post-thumbnail","category-medication","tag-health","tag-medication","tag-new-zealand","tag-newzealand","tag-nz"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/271842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=271842"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/271842\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/271843"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=271842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=271842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=271842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}