Key points
- Semaglutide 2.4 mg (Wegovy) is licensed and NICE-recommended for adolescents aged 12 and over with obesity in the UK
- The STEP TEENS trial showed approximately 16 per cent BMI reduction over 68 weeks in adolescents
- Prescribing must be through specialist paediatric or adolescent weight management services, not GPs
- Parental or guardian involvement is required for patients under 16
- Treatment should be combined with dietary, physical activity and behavioural support
- The side effect profile is similar to adults, with gastrointestinal symptoms being most common
Childhood obesity in the UK: the scale of the problem
Childhood and adolescent obesity is a major public health challenge in the United Kingdom. According to the National Child Measurement Programme, approximately one in three children leaving primary school in England are overweight or obese. By the time they reach secondary school, obesity prevalence continues to rise.
Adolescent obesity is not merely a cosmetic concern. It is associated with significant physical and psychological morbidity, including type 2 diabetes, fatty liver disease, sleep apnoea, musculoskeletal problems, depression, anxiety, low self-esteem and bullying. Research consistently shows that obesity in adolescence persists into adulthood in approximately 80 per cent of cases, making early intervention essential.
Until recently, treatment options for severe adolescent obesity were limited to lifestyle interventions (diet, exercise and behavioural therapy) and, in rare cases, bariatric surgery. The approval of Wegovy for adolescents has added a pharmaceutical option to the treatment pathway.
The STEP TEENS trial
The evidence supporting Wegovy for adolescents comes primarily from the STEP TEENS trial, a randomised, double-blind, placebo-controlled study published in the New England Journal of Medicine.
Trial design
- Participants: 201 adolescents aged 12 to 17 years with obesity (BMI at or above the 95th percentile for age and sex) or overweight with at least one weight-related comorbidity
- Treatment: Semaglutide 2.4 mg weekly injection versus placebo, both combined with lifestyle intervention
- Duration: 68 weeks of treatment plus a 7-week follow-up period off treatment
- Primary endpoint: Change in BMI from baseline
Key results
| Outcome | Semaglutide 2.4 mg | Placebo |
|---|---|---|
| BMI change at 68 weeks | −16.1% | +0.6% |
| Body weight change | −14.7% | +2.8% |
| Achieved 5% or more weight loss | 72.5% | 17.7% |
| Achieved 10% or more weight loss | 61.8% | 8.1% |
| Achieved 20% or more weight loss | 36.8% | 3.2% |
| Waist circumference reduction | −7.0% | +2.8% |
Clinical significance: A 16 per cent BMI reduction in adolescents is transformative. For a teenager with a BMI of 35, this would mean a reduction to approximately 29, moving them from severe obesity to the overweight category. This level of weight loss improves cardiometabolic risk factors, physical function and psychological wellbeing.
What happened after stopping treatment?
During the seven-week follow-up period after stopping semaglutide, participants began to regain weight. This is consistent with findings in adults and underscores the chronic nature of obesity. It suggests that many adolescents may need ongoing treatment to maintain their weight loss.
NICE guidance for adolescents
NICE has issued technology appraisal guidance recommending semaglutide 2.4 mg (Wegovy) for weight management in adolescents aged 12 years and over. The key eligibility criteria include:
- Age 12 to 17 years at initiation
- BMI corresponding to an adult BMI of 35 or above (using age and sex-specific BMI centile charts) with at least one weight-related comorbidity, or BMI corresponding to an adult BMI of 40 or above
- Lifestyle interventions (diet, physical activity, behavioural therapy) have been tried and have not achieved adequate weight loss
- Prescribing through a specialist paediatric or adolescent weight management service with a multidisciplinary team
- Treatment must be combined with ongoing lifestyle support, not used as a standalone therapy
BMI centiles in children: Because children are still growing, BMI is interpreted using age and sex-specific centile charts rather than the absolute BMI thresholds used for adults. A BMI at or above the 95th centile is classified as obese; at or above the 98th centile is classified as severely obese. Specialists use conversion tables to determine the equivalent adult BMI for treatment eligibility.
NHS pathway for adolescent prescribing
The pathway for a teenager to access Wegovy through the NHS involves several steps.
Step-by-step process
- GP assessment: The young person's GP identifies obesity and discusses referral to specialist services
- Referral to tier 3 service: The GP refers to a specialist paediatric weight management service (tier 3). Waiting times vary significantly by region.
- Multidisciplinary assessment: The specialist team (typically including a paediatrician, dietitian, psychologist and specialist nurse) conducts a comprehensive assessment
- Lifestyle intervention: An initial period of structured lifestyle intervention is required before pharmacotherapy is considered
- Prescribing decision: If lifestyle intervention is insufficient, the multidisciplinary team discusses semaglutide as an option with the young person and their family
- Dose titration: Wegovy is started at 0.25 mg weekly and titrated up over 16 to 20 weeks to the target dose of 2.4 mg
- Monitoring: Regular follow-up appointments to assess weight, growth, side effects and psychological wellbeing
- 12-month review: Treatment efficacy is formally reviewed. If there is no clinically meaningful response, stopping treatment is discussed.
Risks and side effects in adolescents
The safety profile of semaglutide 2.4 mg in the STEP TEENS trial was broadly consistent with the adult safety data, but there are specific considerations for adolescent patients.
Common side effects
- Nausea: Reported by approximately 42 per cent of adolescents on semaglutide (versus 14 per cent on placebo). Usually mild and transient.
- Vomiting: Approximately 27 per cent (versus 5 per cent on placebo)
- Diarrhoea: Approximately 17 per cent
- Abdominal pain: Approximately 12 per cent
- Headache: Approximately 10 per cent
Specific adolescent concerns
- Growth and development: There is no evidence from the STEP TEENS trial that semaglutide adversely affects linear growth or pubertal development. However, long-term data beyond 68 weeks is limited, and ongoing monitoring of growth is recommended.
- Bone health: Rapid weight loss in adolescents raises theoretical concerns about bone mineral density. Adequate calcium and vitamin D intake should be ensured.
- Mental health: Adolescence is a vulnerable period for mental health. Weight management treatment should include psychological support. The STEP TEENS trial did not show an increase in depression or suicidal ideation, but vigilance is important.
- Eating disorders: Screening for disordered eating should be part of the assessment process. GLP-1 medications should not be prescribed to adolescents with active eating disorders such as anorexia nervosa or bulimia.
- Gallbladder problems: Rapid weight loss increases the risk of gallstones. Adolescents should be advised to report any right-sided abdominal pain.
Important for parents: Wegovy is a prescription-only medicine that should only be prescribed by specialist services. It is not appropriate for teenagers who simply want to lose a few pounds for cosmetic reasons. It is indicated for clinically significant obesity with associated health risks. Do not purchase GLP-1 medications from online sources for your child without specialist medical supervision.
Parental consent and family involvement
The decision to start Wegovy in a teenager is a collaborative one involving the young person, their parents or guardians, and the multidisciplinary clinical team.
- Under 16: Parental or guardian consent is legally required. The young person should also be involved in the discussion and give their assent (agreement).
- 16 to 17 years: The young person can legally give their own consent to treatment. However, involvement of parents or guardians is strongly encouraged by clinical guidelines.
- Gillick competence: In rare cases, a young person under 16 may be assessed as having sufficient understanding and maturity to consent independently (Gillick competence). This would be assessed by the treating clinician.
Family involvement extends beyond consent. The lifestyle modifications that support Wegovy treatment — dietary changes, regular physical activity and behavioural strategies — are most effective when adopted by the whole family. Parents play a crucial role in creating an environment that supports long-term weight management.
Private prescribing for teenagers
Some private weight loss clinics in the UK offer semaglutide for adolescents. However, this should only be considered if the private service has appropriate paediatric expertise, a multidisciplinary team and a clear clinical governance framework. NICE and the Royal College of Paediatrics and Child Health emphasise that prescribing weight management medications to adolescents requires specialist oversight.
Parents considering private treatment should verify that the prescribing clinician has paediatric experience and that the service offers ongoing monitoring, dietary support and psychological assessment.
Long-term considerations
Obesity is a chronic condition, and the evidence from both adolescent and adult trials suggests that weight regain occurs when GLP-1 therapy is discontinued. This raises important questions about the duration of treatment in young people.
- Some adolescents may need long-term treatment to maintain weight loss
- The optimal duration of treatment is not yet established
- Transition planning from paediatric to adult weight management services is important for continuity of care
- Lifestyle habits established during adolescence provide the foundation for long-term weight maintenance