The World Health Organization published its first guidelines on obesity in children and adolescents on 7 October, as two separate documents: one for children up to the age of 9 and one for adolescents aged 10 to 19. Both put structured diet, physical activity and behaviour-change programmes at the centre of care. For children under 10, WHO advises against weight-loss medicines, bariatric surgery and weight-loss devices altogether. For adolescents, it says medicines, GLP-1 drugs included, should be considered only after a supervised lifestyle programme of at least six months has failed, and only where obesity has already caused complications.
What the guidelines recommend
For adolescents, WHO makes three strong recommendations: a structured dietary intervention supervised by health workers with nutrition knowledge, a physical activity plan, and behaviour-changing interventions such as cognitive behavioural therapy, self-monitoring and goal-setting. Each is rated strong even though WHO grades the evidence behind it as very low quality. Its reasoning is that the benefits are small, but so is the risk of harm.
The recommendation on medicines is weaker. WHO “suggests” drug treatment, a conditional recommendation resting on low-quality evidence, for adolescents who have an obesity-related complication. Its list includes type 2 diabetes, insulin resistance, uncontrolled high blood pressure, abnormal blood fats and mental health problems. The lifestyle programme that has to come first should run for at least six months, and prescribing should happen in a specialised multidisciplinary setting after an assessment of pubertal development, final adult height and psychological stability, with long-term follow-up.
The evidence comes from a Cochrane review WHO commissioned: 37 randomised trials, 25 of them in adolescents only. Of the 31 placebo-controlled trials, 14 tested metformin, six sibutramine, three orlistat and five GLP-1 drugs. Against placebo, over a median of 11 months, medicines lowered BMI by 1.80 points on average (95% confidence interval 1.24 to 2.36; 25 trials, 3,091 participants) and body weight by 5.47 kg (3.5 to 7.45 kg; 20 trials, 2,380 participants). Quality of life, on a 0-to-100 scale, showed no difference: 1.02 points higher, with an interval running from 1.94 lower to 3.98 higher. Stopping treatment because of side effects happened in 40 per 1,000 people on a drug and 23 per 1,000 on placebo, a risk ratio of 1.70 whose interval (0.90 to 3.22) is too wide to say whether that gap is real.
For children under 10, the recommendation against medicines is strong, on low-quality evidence. The review found no trials at all in children under 6, and eight in children aged 6 or older: seven of metformin and one of liraglutide. The recommendation against surgery and devices before 10 is also strong, and WHO grades the evidence for it as “no evidence”: the panel judged that the potential harm to growth and development justified a firm line without trials.
What it changes, and what is not known
WHO guidance is not binding on US doctors, and it is narrower than the US drug labels. The FDA label for Wegovy covers adolescents aged 12 and older with obesity, and the label for Saxenda covers those aged 12 and older with obesity who weigh more than 60 kg, in both cases alongside a reduced-calorie diet and increased physical activity. Neither label requires a failed six-month programme first, or an existing complication. WHO’s age line sits lower, at 10, but its conditions are stricter.
The pooled figures above also mix old and new drugs. Sibutramine was withdrawn from the US market in 2010, and metformin is not approved for weight loss. WHO’s pooled table gives no GLP-1-only figure; the guideline instead cites a 2025 network meta-analysis in which semaglutide outperformed the other medicines on percentage change in BMI. The adolescent trial evidence for semaglutide and liraglutide is covered in our drug overviews.
Almost every recommendation in both documents rests on evidence WHO itself rates low or very low. The drug trials lasted between three and 16 months, so they say little about effects on growth, puberty or weight regain over years, and only five placebo-controlled GLP-1 trials fed the review. The studies came mostly from high-income countries, while the guidelines are written for primary care in health systems worldwide. WHO describes the field of obesity medicines as rapidly evolving, and its recommendation does not name any specific product.
Sources: World Health Organization, “WHO issues first global guidelines on child and adolescent obesity”, news release, 7 October 2026; WHO guideline on the integrated management of obesity in adolescents (ISBN 978-92-4-012387-8), WHO, 2026; WHO guideline on the integrated management of obesity in children (ISBN 978-92-4-012339-7), WHO, 2026; FDA prescribing information for Wegovy and Saxenda, indications sections, via openFDA (label versions effective 23 April 2024 and 25 February 2026).
