How Does Mounjaro Work for Weight Loss

What Is Mounjaro?

Mounjaro, the brand name for tirzepatide, is a next generation injectable medication that is revolutionising the treatment of diabetes and obesity. It is part of a new class of drugs called dual GIP/GLP-1 receptor agonists. That means it replicates the impact of two hormones from the body, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP).

These hormones, which are released in the gut after a meal and promote regulation of blood sugar, insulin production, appetite and digestion, are widely believed to be at the centre of how bariatric surgery works. Through the action of these hormone receptors, Mounjaro provides a two-action treatment for both type 2 diabetes and obesity.

Is Mounjaro Approved in the UK?

Yes, Mounjaro is approved for medical use in the UK. It was first licensed for the treatment of type 2 diabetes but has since been approved for use in weight management in adult patients who are obese or overweight with comorbidities including hypertension, obstructive sleep apnoea or high cholesterol.

 

How Does Mounjaro Work?

Unlike any other existing weight loss drugs that either suppress people’s appetites or regulate their blood sugar, Mounjaro aims at both systems by mimicking the hormones GLP-1 and GIP. These are members of a class of compounds known as incretins, which assist the body to manage glucose after meals.

 

GLP-1 Effects

• Food-induced insulin secretion is promoted
• Inhibits glucagon, the hormone that increases blood sugar
• Slows down how long it takes for your stomach to empty and you feel full
• Signals the brain to lower appetite

GIP Effects

• Improves insulin increments and GLP-1
• Aids in the metabolism of fat to help the body break down fat stores.
• May enhance metabolism, but more studies are needed.

The combined effect of these actions is a superpower for controlling blood sugar levels and for long-term weight loss.

 

Mechanism of Action

The difference in tirzepatide is that it binds and activates both the GLP-1 and GIP receptors, much like the hormones themselves do when responding to food intake.

When you take Mounjaro:

• This allows appropriate increases in insulin to lower elevated blood sugar levels.
• Glucagon production is lessened, a factor that serves to moderate glucose levels
• Gastric emptying is slowed, which means you eat less by feeling fuller longer
• Appetite is also suppressed, making it easier to stick to a calorie restricted diet

The combination of effects results in:

• Fewer food cravings
• Lower calorie consumption
• Enhanced fat breakdown
• Reduced insulin resistance

Both of these mechanisms lead to clinically significant and durable weight loss.

 

Onset of Effects

Some people also describe having less of a desire to eat and eating less amounts in the big meals, typically after 1 to 2 weeks of using Mounjaro. Most people begin to lose weight and a noticeable weight reduction is seen within the first month.

 

Weight Loss Timeline

Clinical data suggests:

• 16% of their starting weight when having 5mg a week
• 21.4% of their starting weight when having 10mg a week
• 22.5% of their starting weight when having 15mg a week

Mounjaro makes a very slow, but steady loss of weight. It helps the body lose fat in a way that spares muscle and avoids big reduction in metabolic rate.

 

Factors That Influence Results

• Initial dose and how quickly the dose increases
• Consistency of use
• Dietary and physical activity patterns
• Baseline BMI and comorbidities
• Whether used in combination with other medicines, such as metformin

 

SURMOUNT-1 Trial

According to a key trial, those without diabetes lost 22.5% of their body weight over 72 weeks on the 15 mg dose. That is roughly equivalent to 23 kilogram weight loss in someone initially weighing 100 kg.

 

SURPASS Trials

Performed on people with type 2 diabetes:

• Had impressive reductions in HbA1c
• Reported sustained weight loss of 8 and 16% with dosing.
• Favourably compared to insulin and semaglutide

These findings indicate that tirzepatide might be more potent than currently available single-hormone GLP-1 drugs.

 

Semaglutide vs. Tirzepatide

Ozempic and Wegovy contain semaglutide, which is a GLP-1 receptor agonist. But it only mimics one hormone, one that suppresses appetite and enhances insulin sensitivity.

Tirzepatide gets half its name from its two hormone mimics and demonstrated more weight loss and better glucose control than the comparison drugs in head-to-head comparisons.

Semaglutide (Wegovy/Ozempic)

• Hormone activation: GLP-1 only.
• Max weight loss (avg): 13.7%.
• Effect on insulin sensitivity: Yes.
• Appetite suppression: Strong.
• Fat metabolism support: Moderate.
• Onset of noticeable results: 4 – 8 Weeks.

Tirzepatide (Mounjaro)

• Hormone activation: GLP-1 + GIP.
• Max weight loss (avg): Up to 20.2%.
• Effect on insulin sensitivity: Yes (greater impact).
• Appetite suppression: Stronger (dual action).
• Fat metabolism support: Enhanced via GIP.
• Onset of noticeable results: 2 – 4 Weeks.

Mounjaro weight loss injections are clinically more effective than GLP-1 based drugs though individual results do vary.

 

Common Side Effects

These side effects are usually mild and will go away as your body becomes accustomed to the medication, they include:

• Nausea
• Vomiting
• Diarrhoea
• Constipation
• Fatigue
• Decreased appetite
• Bloating

Less Common or Serious Side Effects

• Dizziness
• Injection site irritation
• Pancreatitis (rare but serious)
• Renal function decrease (patients with a history of kidney problems)

Medical supervision during treatment, particularly when increasing the maximum maintenance dose or when combining Mounjaro with other medicines including insulin, is necessary.

 

Conclusion

Mounjaro is one of the most important drugs in the field of obesity and type 2 diabetes . Through mimicry of two crucial hormones, it is a more holistic approach than past therapies. It not only regulates blood sugar, it also alters the way the body responds to food and hunger.

 

Who Can Take Mounjaro?

Mounjaro is suitable for adults who:

• Have type 2 diabetes, particularly if not well-controlled blood sugar
• Have a Body Mass Index (BMI) ≥30 (obese) or BMI ≥27 (overweight) with co-morbid conditions due to obesity.
• Tried lifestyle changes and other weight loss methods and need another option for their weight loss journey.

It is not recommended for:

• Children or teens
• Pregnant and nursing mothers
• Those who have ever had pancreatitis or certain thyroid cancers

Before you start tirzepatide, talk to your doctor about whether it’s a good fit for you as well as a personalised programme.

 

FAQs

• What is Mounjaro and how does it aid in weight loss?

Mounjaro is a drug that mimics two hormones naturally present in your body that tell you to stop eating and help keep your blood sugar stable. This makes you less hungry, eat less and lose weight slowly.

• How quickly can I expect to see weight loss results with Mounjaro?

Some people perceive a reduced appetite in the first two weeks. You may notice gradual average weekly weight loss, but bigger changes generally occur over several months, particularly if you remain consistent.

• Is Mounjaro approved for weight loss treatment in the UK?

Yes, Mounjaro is UK Approved for both type 2 diabetes treatment as well as weight loss. It is aimed at people who are overweight, or who have related health problems.

• What are the common side effects of Mounjaro?

The most frequent side effects are feeling sick (nausea), upset stomach, constipation and reduced appetite. These are usually mild and improve as your body gets used to the medicine.

• How does Mounjaro compare to other weight loss injections like Ozempic?

Mounjaro functions differently than Ozempic as well, addressing two hunger-regulating hormones instead of one. This would mean it could help some people lose more weight than other similar medications.