What Is Actually Approved

This gets discussed as though it were a grey area. For one medication it is not.

• ▪Semaglutide 2.4mg (Wegovy) — FDA-approved for adolescents aged 12 and over with obesity on 3 January 2023.
• ▪Liraglutide (Saxenda) — approved in this age group before semaglutide was.
• ▪Tirzepatide (Zepbound, Mounjaro) — not approved under 18 as of August 2026. The SURMOUNT-ADOLESCENTS and SURMOUNT-ADOLESCENTS-2 trials in 12- to 17-year-olds are ongoing.

That last distinction matters practically. A teenager prescribed tirzepatide is receiving an off-label prescription — which is lawful and can be entirely appropriate, but it means the dosing, the safety monitoring and the evidence base in that age group have not been through an FDA review. If a telehealth service offers tirzepatide to a 16-year-old without saying that, it is worth asking why not.

The Trial the Approval Rests On

STEP TEENS, published in the New England Journal of Medicine in 2022, is the study behind the approval, and it is worth knowing in some detail rather than as a headline.

It randomised 201 adolescents aged 12 to under 18, with a BMI at or above the 95th percentile for age and sex, or at or above the 85th percentile with at least one weight-related condition. The primary outcome, change in BMI at 68 weeks, was −16.1% in the semaglutide group against +0.6% on placebo. Seventy-three per cent of those on semaglutide lost 5% or more of their body weight — a result broadly comparable to what the adult trials produced.

What the Guidelines Say, and the Word That Gets Dropped

In January 2023 the American Academy of Pediatrics published its first comprehensive clinical practice guideline for the evaluation and treatment of children and adolescents with obesity. Its pharmacotherapy recommendation is that clinicians should offer adolescents aged 12 and over with obesity weight-loss pharmacotherapy, according to each medication's indications, risks and benefits, as an adjunct to intensive health behaviour and lifestyle treatment.

That guideline treats intensive behavioural and lifestyle treatment as the cornerstone of care, with medication added to it. In practice the behavioural component is the part that is hardest to access — it is time-intensive, often not covered, and frequently unavailable locally — which creates an obvious pressure to prescribe the medication alone because it is the part that can actually be obtained. That is a real-world gap between the guideline and what many families are offered, and it is worth naming when you are deciding.

The Concerns Specific to a Growing Body

Everything on our side effects guide applies. These are the additional considerations that exist because the patient is still developing.

Bone

Peak bone mass is largely accrued between roughly age 11 and the mid-twenties, and what is built in that window shapes fracture risk decades later. In adults, rapid weight loss — on the order of 14% or more over three to four months — has been associated with measurable declines in bone mineral density. Researchers have raised the concern that the same dynamic during the accrual window could matter more, and studies of bone development in adolescents on these medications are ongoing rather than concluded. Adequate protein, adequate calcium and vitamin D, and resistance exercise are the levers, and they are the same levers described in our piece on muscle loss.

Nutrition for growth, not just for activity

An adult eating far less is under-fuelling daily function. An adolescent eating far less is also under-fuelling growth and puberty. Appetite suppression is the mechanism of the drug, so the risk of an unbalanced or inadequate intake is structural rather than incidental — and our guide to nutrient deficiencies covers what tends to fall short first.

Eating disorders

This is the concern we would weight most heavily. Adolescence is when disordered eating typically emerges; appetite suppressants are known to be misused in this age group; and body-image pressure, social media and weight-sensitive sports — wrestling, gymnastics, dance, distance running — all raise the risk. A medication that makes eating less easier is not neutral in that context. Screening for disordered eating before and during treatment is not a formality, and a family history of eating disorders is a reason for a much more careful conversation.

Questions Worth Asking the Prescriber

• ▪Is this an approved indication for this medication at this age, or off-label?
• ▪What intensive behavioural and lifestyle support comes with it, and how do we access it?
• ▪How will growth, puberty and bone health be monitored, and how often?
• ▪What screening for disordered eating happens before we start, and what would prompt stopping?
• ▪What protein and micronutrient targets should we be aiming for, and will bloods be done?
• ▪What is the intended duration, and what is the plan when it ends?
• ▪What happens if it becomes unavailable or unaffordable partway through?
• ▪Does contraception need to be part of this conversation?

The Practical Side, Briefly

One mundane thing does need managing, and it is worth handling deliberately because of how loaded it can become. A teenager whose body is changing will outgrow clothes in the wrong direction, at an age when what you wear is not a trivial matter, and while their peers are outgrowing clothes in the usual one.

The principles from our piece on clothes and body image apply, with one addition specific to adolescents: keep clothing out of the reward economy. Buying something as a prize for a number on a scale ties self-image to weight in exactly the age group where that link is most dangerous. Replace things because they no longer fit, in the same matter-of-fact way you would for a growth spurt.

Tillys is one option for that — a US specialty retailer aimed at teens and young adults, selling skate, surf, streetwear and activewear clothing, footwear and accessories from brands including Vans, Billabong, Hurley and Volcom. Returns run 30 days from the order or purchase date, with items needing original condition, packaging and tags; online orders can be returned by post or in store but cannot be exchanged online, and several categories including sunglasses, watches, jewellery and clearance items are final sale.

Frequently Asked Questions

Where to Go Next

• ▪Nutrient deficiencies on a GLP-1 — what falls short first when intake drops, and what to monitor
• ▪Muscle loss on a GLP-1 — the protein and resistance-training case, which matters more here
• ▪Mental health support on a GLP-1 — including what regulators concluded about mood