If you’re reading this while deciding whether to start Mounjaro or Wegovy — or you’ve already had your first injection and feel a mix of hope and unease — you’re not alone. Over the past few years, the use of GLP-1 weight loss injections has increased dramatically, something that’s very visible day to day in community pharmacy.

As a pharmacist, what concerns me most isn’t the medication itself, but how often people start it with very little understanding of what it’s doing to their body or what the long-term plan looks like. Conversations usually focus on starting doses and titration schedules, while discussions about how — or whether — someone will come off the medication are often missing altogether.

I’m not anti–weight loss medication. I’ve seen how life-changing these drugs can be for people who’ve struggled with obesity or diabetes despite genuine lifestyle efforts. But I do believe medications work best as bridges, not destinations— tools that support change rather than replace it. And like any powerful tool, they come with trade-offs that are worth understanding before you begin

Mounjaro is frequently described as a “miracle drug.” While it can be life-changing for people with obesity or type 2 diabetes, it’s not without consequences. As someone who has never lived with obesity or diabetes, I don’t pretend to fully understand how difficult weight loss can be despite lifestyle changes.

At the same time, these medications can make weight loss feel more achievable by quieting appetite and changing hunger signals. If you’re thinking, “Once I lose the weight, I’ll feel more motivated to eat healthier and exercise,” you’re not alone — and for some people, that does happen. But it isn’t guaranteed.

This article isn’t about discouraging the use of Mounjaro or Wegovy. It’s about helping you understand what these medications do, what we don’t yet know, and why they may not be intended as lifelong treatments.

How Mounjaro Works in the Body

Our bodies are designed to maintain balance through complex feedback systems involving hormones and receptors. Two key hormones involved in appetite and glucose regulation are:

  • GLP-1 (glucagon-like peptide-1)
  • GIP (glucose-dependent insulinotropic polypeptide)

These hormones are naturally produced in the gut and act on multiple organs, including the brain, pancreas, stomach, and fat tissue.

Mounjaro (tirzepatide)

Mounjaro is a dual GLP-1 and GIP receptor agonist, meaning it activates both receptors simultaneously.

This leads to:

  • reduced appetite and increased satiety (via brain signalling)
  • slower gastric emptying
  • increased insulin secretion (glucose-dependent)
  • improved blood sugar control

GLP-1 is well known for its role in appetite suppression through direct action on appetite centres in the brain. GIP’s role is more complex — historically associated with fat storage — but when combined with GLP-1, it appears to enhance weight loss and metabolic outcomes. This dual action is likely one reason Mounjaro has shown greater weight loss than GLP-1–only medications.

That said, this mechanism is still being studied, and long-term effects remain uncertain.

How Wegovy Works

Wegovy (semaglutide) is a GLP-1 receptor agonist only.

It works by:

  • activating GLP-1 receptors in the brain to reduce appetite
  • slowing stomach emptying
  • increasing insulin secretion and reducing glucagon release

Wegovy has strong evidence for weight loss and cardiovascular benefit, particularly in people with obesity. However, compared to Mounjaro, average weight loss tends to be less pronounced, which is why Mounjaro is often perceived as “more effective.”

Metabolic and Long-Term Considerations

GLP-1–based medications have shown benefits in:

  • blood glucose control
  • insulin sensitivity
  • some lipid parameters

However, potential risks include:

  • nausea, vomiting, and gastrointestinal intolerance
  • gallbladder disease
  • rare cases of pancreatitis

Because these medications influence pancreatic function and lipid metabolism, it’s reasonable to have baseline blood tests, including cholesterol and triglycerides, before starting — and to monitor them during treatment.

While hypoglycaemia is uncommon when these medications are used alone, we still lack long-term data on:

  • prolonged pancreatic stimulation
  • changes in beta-cell mass
  • long-term hormonal adaptation

What Happens When You Stop Mounjaro or Wegovy?

When these medications are stopped, appetite typically returns, sometimes quite noticeably. The speed and extent vary between individuals.

People tend to transition more successfully when weight loss medications are used alongside lifestyle changes, including:

  • adequate protein intake
  • resistance or strength training to preserve muscle mass
  • sustainable eating patterns (not extreme restriction)

This doesn’t mean eliminating carbohydrates or exercising excessively — it means building habits that can survive without medication support.

Final Thoughts: Use With Intention

Mounjaro and Wegovy can be powerful tools — but tools work best when used intentionally, with a clear plan.

Before starting, consider asking:

  • What is my long-term plan?
  • What habits am I building while on this medication?
  • How will I come off it?

Understanding these medications before starting helps ensure they support your health — rather than quietly replacing it.

If you have questions or would like pharmacist-led guidance around Mounjaro or Wegovy, feel free to reach out at wanderingoose97@gmail.com.

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