What is BMI and why it matters here

BMI, or body mass index, is a simple calculation of weight and height. It is often used in healthcare to assess whether someone may be underweight, a healthy weight, overweight, or living with obesity.

A BMI between 18.5 and 24.9 is generally considered a healthy range. A BMI between 25 and 29.9 is seen as overweight. A BMI of 30 or above is classed as obese.

BMI is not perfect. It does not measure muscle, body fat, or account for different ethnic backgrounds. Still, it remains a widely used screening tool in weight management.

Mounjaro eligibility at a glance

In most UK clinics, Mounjaro may be considered if someone has a BMI of 30 or above. It may also be prescribed with a BMI of 27 or more if there are weight-related health conditions.

Examples include type 2 diabetes, high blood pressure, or sleep apnoea. These conditions raise health risks, so treatment may be offered at a lower BMI.

The final decision is always made by a clinician. They will look at your health history, current medicines, and personal goals before offering treatment.

If your BMI is close to the line

If your BMI is between 27 and 30, your overall health will be assessed. A clinician will check for risk factors like raised cholesterol, pre-diabetes, or high blood pressure.

Sometimes lifestyle support such as diet and exercise advice will be tried first. A recent pattern of weight gain or previous weight loss attempts will also be considered.

Your commitment to follow-ups and healthy habits will guide whether Mounjaro is the right choice for you.

Who should not use Mounjaro

Mounjaro is not suitable if you are pregnant, planning pregnancy, or breastfeeding.

It is not recommended for people with a history of pancreatitis or severe gastrointestinal disease. Those with a personal or family history of certain thyroid cancers or syndromes linked to thyroid tumours should also avoid it.

Anyone with unexplained symptoms or red flags will need further medical review before treatment.

Dosing and how it is stepped

Mounjaro is given as a once-weekly injection. Treatment usually begins with the lowest dose, such as 2.5mg, to allow the body to adjust.

If tolerated, the dose is slowly increased over several weeks to improve results. Gradual increases help reduce tummy-related side effects such as nausea.

This process, called titration, ensures that treatment is safe and more comfortable to continue.

What results to expect and when

The first changes noticed are often reduced appetite and fewer cravings. Weight loss usually develops over the following months.

Results are supported by a balanced diet rich in protein and fibre, regular sleep, and daily physical activity.

A review at 12 to 24 weeks helps track progress and adjust treatment if needed.

Side effects and simple fixes

Mounjaro may cause nausea, reflux, or constipation, especially at the start. Eating smaller meals, drinking more fluids, and adjusting dose timing can help.

If side effects are ongoing or severe, medical advice is needed. Never double up a missed dose without speaking to your clinician.

Your pre-consultation checklist

Before booking, it helps to prepare some details. Note your recent weight, height, and BMI.

Bring a list of your current medicines and any long-term health conditions. Share what weight loss strategies you have tried before and how they worked.

Consider your budget for treatment and whether you can attend regular follow-ups.

Frequently asked questions

Can I get Mounjaro if my BMI is under 27?

Usually not, unless there are significant health conditions.

Do I need to change my diet if I use Mounjaro?

Yes, healthy eating is still important for best results.

How long will I need to stay on it?

This depends on progress, goals, and clinical review.

What if I have type 2 diabetes?

Mounjaro may be suitable, but assessment is required.

Can I drink alcohol on Mounjaro?

Moderate alcohol may be safe, but check with your clinician.