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Getting started with weight loss medications

Starting a new medication can feel overwhelming, but you don’t have to navigate it alone. This guide was created to give you everything you need to feel informed and confident on your weight loss journey.

Dr Adam Abbs

Medical Director

The history of GLP-1s

While many people think of medications like Wegovy and Mounjaro as new, the class of medication that they belong to were originally developed as a type 2 diabetes treatment. The first medication was FDA-approved in 2005 and licensed for use in the UK in 2007. Researchers discovered that these drugs not only helped regulate blood sugar but also led to significant weight loss. Over time, newer GLP-1 treatments like liraglutide (Saxenda) and semaglutide (Wegovy) were specifically approved for obesity management.

How it impacts your body

GLP-1s work in the body by affecting multiple organs. They help to regulate appetite, metabolism, and fat storage.

This means that Mounjaro mimics two incretin hormones instead of just one. GIP also enhances insulin secretion after you eat and reduces appetite, which increases the effectiveness of Mounjaro.

Appetite suppression: Your treatment activates receptors in parts of the brain called the hypothalamus and brainstem to reduce your appetite and increase feelings of fullness. It also works on the dopamine dependent systems in the brain, reducing the desire to snack by reducing the rewarding effects.

This helps to reduce “food noise” which is an informal term which describes the feeling of constant food-focused thoughts, such as what to eat, when to eat, and how much to eat.

Slows digestion: Your medication slows down the rate at which food leaves your stomach, helping you stay fuller for longer.

Blood sugar regulation: After eating, your treatment enhances insulin secretion from your pancreas, helping to control blood sugar levels. Mounjaro also increases insulin sensitivity, which means your cells can respond more effectively to insulin. When cells respond effectively to insulin, they efficiently take up glucose from the bloodstream and help to keep blood sugar levels within a healthy range to reduce cravings.

How do I know which treatment is right for me?

This short video addresses the key differences between Wegovy and Mounjaro, as well as the benefits and considerations of each.

How Mounjaro works

Mounjaro contains the active ingredient tirzepatide, which mimics two naturally occurring hormones in your body, GLP-1 and GIP. These hormones are released after you eat to help manage blood sugar levels and appetite. They tell your body to release insulin when needed, slow the rate food leaves your stomach, and help you feel fuller for longer. By mimicking both GLP-1 and GIP hormones, Mounjaro helps support steady blood sugar control and reduces hunger, which can lead to weight loss when combined with healthy lifestyle changes.

In clinical studies, people using Mounjaro (tirzepatide 15mg) lost an average of around 21% of their body weight after 72 weeks, and up to 25% in some cases. (Based on results from the SURMOUNT-1 trial of adults with obesity.)

How Wegovy works

Wegovy contains semaglutide, which mimics the natural GLP-1 hormone your body releases after meals. GLP-1 helps regulate blood sugar levels, slow digestion, and reduce appetite. That way, it helps you feel satisfied with smaller portions and fewer cravings.

In clinical studies, people using Wegovy (semaglutide 2.4mg) lost an average of around 15% of their body weight after 68 weeks, and up to 20% in some cases. (Based on results from the STEP-1 trial of adults with obesity.)

Your first order should include

1 x medication pen
4 x disposable needles
Disposable alcohol wipes (Mounjaro customers only)
Sharps disposal box
Patient information leaflet
Welcome booklet

Storing your medication

Keep your medication in the fridge between 2-8°C before your first use and between doses.
Keep the pen cap on to protect the medication from light and contamination.
Track expiration dates and set reminders to replace your medication if needed.

Never store your medication in a freezer. If the medicine inside the pen gets frozen, do not use it even if you defrost it.

Getting ready to inject

Injecting your treatment for the first time might feel intimidating, but many patients find it to be a quick and easy process. Follow the instructions below to make it a seamless part of your weekly routine.

Pick your injection day

Wegovy and Mounjaro are administered once a week. Choose a day that works best for your routine and set a reminder on your phone or calendar. Staying consistent helps your body adjust and makes it easier to remember.

Choosing Friday or Saturday gives you time to manage potential side effects (like nausea or fatigue), and adjust your routine without workday stress. If weekends tend to trigger binge eating or overindulgence, injecting towards the end of the week (e.g., Thursday or Friday) can help curb weekend cravings, promoting more mindful eating habits.

On the other hand, some people prefer early-week injections (like Monday) to reinforce healthy habits and maintain structure throughout the week.

Make sure to read all the Patient Information Leaflet (PIL) provided with your medication. Understanding what to expect can make your journey smoother.

Mounjaro PIL Wegovy PIL

Your first injection

Injecting for the first time might feel daunting, but the needle is very small and many people feel little to nothing at all. That's completely normal, and it doesn't mean anything went wrong or that the dose didn't go in.

After you inject, run through these three checks to confirm your dose has been delivered:

The dose counter has returned to zero in the pen window
You held the pen against your skin for the full time (usually 5-6 seconds, but check the instructions of your specific pen)
The plunger has moved down inside the pen

If all of those things happened, your dose has been delivered. Not feeling pain or much sensation isn't a bad sign, it's actually how the pen is designed to work.

What you might notice afterwards

A few things are common after an injection and all of them are harmless:

A small drop of blood at the injection site. Press gently with a clean cotton pad or tissue for a minute or two.
A small raised bump under the skin that settles quickly on its own
Mild redness, slight itching, or a bruise that fades over a few days
A tiny droplet of liquid on the needle tip. This is residue from the tip of the needle.

None of these mean your dose hasn't worked or that anything has gone wrong. They're simply your body responding normally to an injection.

Why weight loss can stall (and why that's normal)

Week one: the scale moves. Week two: things slow down. Week three: suddenly… nothing.

This is one of the most common moments when people question whether or not their medication is working.

In reality, it's often a completely normal part of how the body adjusts.

Early weight changes are often influenced by water shifts and digestion changes. Around weeks two and three, your body is still recalibrating and adjusting appetite signals, slowing digestion, plus settling into a new rhythm.

During this time, appetite changes often happen before fat loss becomes obvious on the scale.

So a pause on the scale doesn't mean nothing is happening. It can simply mean your body is adapting to the medication and finding its balance.

Dose changes can sometimes help, but they're rarely the first or most helpful step. Often, the most powerful thing is simply giving your body a little more time.

Slower weight loss is the right kind of progress

Online, it can sometimes look like everyone else is losing huge amounts of weight overnight.

But most of those dramatic numbers are water weight or highlight-reel moments, not the full picture. In clinical studies, losing around 0.5–1 kg (1–2 lb) per week is considered meaningful, effective, and sustainable progress.

Weight loss that happens gradually tends to be easier for the body to maintain long-term. So if your progress feels slower than what you see online, that doesn't mean something is wrong. It often means your body is losing weight at a steady, sustainable pace.

And in the long run, that kind of progress is often easier to maintain.

You might see posts online from people saying they lost ten or fifteen pounds in a single week. It's helpful to understand what those numbers often represent.

Rapid early weight loss is usually mostly water, not fat. Losing one pound of body fat requires roughly a 3,500-calorie deficit. Losing several pounds of fat in a single week would require an extremely large calorie deficit that is unrealistic (and unhealthy) for most people.

There's also a "highlight reel" effect online. People who have dramatic results may be more likely to post about them. For every post celebrating a big drop on the scale, many more people are having steady, successful weeks that simply aren't shared.

Your journey is your own. Comparing it to someone else's best moments online rarely gives a fair picture.

What happens when i reach a healthy weight?

At MedExpress, achieving a healthy weight is just the beginning of your weight loss journey. Maintaining your success is equally important. We understand you might feel anxious at the thought of stopping weight loss medications once you reach a healthy BMI. The good news is that reaching your goal isn't the end of your journey; it's the beginning of maintaining your progress. That's why we continue to support you, even after you've achieved your goals. Rather than stopping medication automatically, our prescribers can continue to provide your weight loss medication for as long as you need to prevent weight regain.

We conduct regular check-ins to monitor your progress, adjust your treatment if necessary, and address any concerns you may have. This means you can feel confident in maintaining the results you have worked hard to achieve.

What is titration?

Titration is the process of gradually adjusting your medication dose over time. This helps your body get used to the treatment and can reduce potential side effects. It’s a safe and supported way to find the dose that works best for you.

It works with GLP-1 medications like Wegovy and Mounjaro by starting at a low dose and may be increased gradually if needed. At MedExpress, our clinicians review your progress regularly and will only adjust your dose if it’s safe, appropriate, and helping you make steady progress. We’ll keep you informed every step of the way with reminders and guidance designed to make treatment simple and supportive.

Finding your ideal dose

There’s no single “right” dose for everyone. Your clinician will work with you to find what feels best, balancing comfort, side effects, and results. Some people stay on a lower dose for longer; others move up over time. The goal is always the same: to help you feel well, manage side effects, and see sustainable progress at a pace that suits you.