Does Mounjaro target fanny fat? What the evidence shows

Step 1: understand how Mounjaro produces weight loss in the first place

Mounjaro is a dual GIP and GLP-1 receptor agonist, the only medicine of its kind licensed in the UK for weight management. It activates two gut-hormone receptors that regulate appetite and fullness, and it slows the rate at which the stomach empties. The result is that most people find they feel satisfied on considerably less food without having to consciously fight hunger.

That reduction in calorie intake is what drives fat loss. The body draws on stored energy reserves (fat) to make up the shortfall. This process happens systemically: your liver, visceral tissue (the fat wrapped around internal organs), subcutaneous fat (the layer under your skin), and fat deposited around the hips and lower body are all drawn on over time. You can learn more about how the treatment works on our Mounjaro overview page.

Tirzepatide is sometimes called the skinny jab, and our page on Mounjaro as a skinny jab explores what that label means in practice, though that shorthand does a disservice to what is a clinically complex medicine. It is worth reading past the headlines. What the SURMOUNT-1 trial, published in the New England Journal of Medicine, actually showed was an average body-weight reduction of around 20–21% at the highest dose over 72 weeks, a result that reflects whole-body fat reduction, not a cosmetic spot-reduction.

Step 2: understand why fat does not disappear from one place on command

Where your body stores fat, and which reserves it burns first, is almost entirely determined by genetics and hormones, particularly sex hormones. Women tend to carry more subcutaneous fat around the hips, thighs and lower abdomen; men more visceral fat around the waist. These patterns shift gradually with age and with weight change, but no medicine, exercise plan or diet changes the fundamental biology of where your body prefers to store energy.

This means that fat around the lower body (what some people call their fanny or hip fat) does reduce as total body fat falls. It just reduces as part of the whole, not in isolation. For some people, particularly women, this area may be one of the last to visibly change even as the scales move significantly. That is a normal biological pattern, not a failure of the treatment.

If you are noticing unexpected physical changes while on treatment, including any upper respiratory symptoms that feel connected, it is worth raising those with your prescriber rather than assuming they are unrelated.

Step 3: what the trial evidence says about waist circumference and body composition

The SURMOUNT programme enrolled thousands of adults across its trials, and secondary endpoints included waist circumference, not just total weight. Participants on tirzepatide saw meaningful reductions in waist measurements alongside overall weight loss, which reflects genuine reductions in both visceral and subcutaneous abdominal fat.

This matters clinically because visceral fat (the deep abdominal kind, not visible from the outside) is strongly associated with cardiovascular risk and metabolic conditions. Reducing it is one of the meaningful health benefits of significant weight loss, beyond appearance alone. The NICE appraisal of tirzepatide (TA1026) published in December 2024 reviewed this evidence base and recommended the medicine for eligible adults on the NHS, precisely because the health gains extend well beyond the number on the scales.

For context on what treatment costs in the private market, including what a legitimate price actually covers, our cost and pricing guide lays out what to expect and what questions to ask any provider.

Keep the pen in the fridge door between uses, some people find that simple routine prompt is enough to keep weekly injections consistent, which matters for the steady weight reduction the trials measured.

Step 4: what this means if you are considering Mounjaro

If your goal is to reduce body fat (including around the abdomen and lower body) Mounjaro is among the most effective licensed options currently available in the UK. The weight lost is real and substantial for many people in the trials. What it cannot do is guarantee that fat leaves a particular area first, or exclusively.

A prescriber assessing your suitability will look at your BMI, any weight-related health conditions, your medical history and your goals. Lower BMI thresholds may apply for some ethnic backgrounds under UK guidance. That conversation is the right place to set realistic expectations about how weight loss tends to unfold on this treatment.

If you want to understand the broader weight-loss treatment landscape in the UK before committing to a consultation, that is a reasonable place to start. Our clinical team at nume is made up of GPhC-registered Independent Prescribers who review every consultation personally, and if you are buying for someone else going through treatment, our funny Mounjaro gifts page has some thoughtful ideas for showing your support. Start your free consultation when you are ready, with no obligation beforehand.