How To Start Losing Weight: What You Need to Know Before You Begin

The start of a new year is when many people feel most motivated to make a change, and for a growing number that includes considering a weight loss injection like Mounjaro or Wegovy. If you have been thinking about it, taking that first step can feel significant, particularly when you are not quite sure what the process involves or what the first few weeks will actually feel like.

The good news is that starting treatment is more straightforward than many people expect, and knowing what to anticipate makes the whole thing far less daunting. This is a practical, clinician-led guide to getting started the right way: how to access treatment, what the starting dose looks like, what to expect in your first week, and how to set goals that are realistic and sustainable.

As with any prescription medication, GLP-1 treatment is not suitable for everyone, and a clinician needs to confirm it is right for you before you begin. But if it is a good fit, there has never been an easier time to get started safely.

How do you get started with weight loss injections?

Getting started with GLP-1 treatment is designed to be simple. It begins with a consultation and a review of your medical history, during which a clinician looks at your general health, any existing conditions, the medications you take, and whether you have any contraindications that would make treatment unsuitable.

Alongside this, your eligibility is assessed. This usually takes into account your BMI and whether you have any weight-related health conditions, as well as your wider medical picture. A clinician must confirm that treatment is appropriate before any prescription is issued, which is an essential safeguard rather than a hurdle.

Because the process is completed online with SwiftDoctor, it is often quick. For eligible patients, treatment can frequently begin within days rather than the weeks a traditional referral might involve, provided you meet the eligibility criteria for GLP-1 treatment.

What is the starting dose for Mounjaro or Wegovy?

Both medications are started at a low dose that is increased gradually over several weeks, a process known as titration. Starting low gives your body time to adjust and significantly reduces the likelihood of side effects, particularly the gastrointestinal ones that are most common early on. [1][2]

Mounjaro (tirzepatide) typically begins at 2.5 mg once weekly for the first four weeks, before increasing to 5 mg. From there, the dose can be increased in 2.5 mg steps no more often than every four weeks, up to a maximum of 15 mg, depending on response and tolerability. [1] However some patients remain on 2.5 mg if it’s effective for them.

Wegovy (semaglutide) usually starts at 0.25 mg once weekly and is increased every four weeks through a series of steps (0.5 mg, 1 mg, then 1.7 mg) to a maintenance dose of 2.4 mg, a process that takes around 16 weeks. [2]

Crucially, these are typical schedules rather than fixed rules. Dose increases are guided by a clinician based on how you are tolerating treatment and how you are responding, not by the calendar alone. If a dose does not feel comfortable, staying on it a little longer before stepping up is often the right call. It’s especially worth staying on the same dose if you are losing weight.

      "It's natural to want results as quickly as possible, but with weight loss medications, slower is often better. Starting on a low dose and increasing gradually gives the body time to adapt, which helps minimise side effects such as nausea and improves the likelihood that patients can stay on treatment long term. Sustainable weight loss isn't about reaching the highest dose quickly—it's about finding the lowest effective dose that delivers results while remaining comfortable and safe for the individual."

— Dr Saira Bano, GP & Co-Founder, SwiftDoctor

What can you expect in your first week?

The first week is mostly a period of gentle adjustment. Many people notice a subtle change in appetite quite early, often feeling satisfied with smaller portions or thinking about food a little less than usual. This tends to build over the following weeks rather than arriving all at once.

Some people also experience mild digestive side effects in the early days, most commonly nausea, and occasionally other gastrointestinal symptoms. These are usually mild, reflect your body adjusting to the medication, and tend to settle as you continue. [1][2]

A few practical habits, often discussed with patients, can help you feel more comfortable: eating smaller meals, avoiding rich or fatty foods around the time of your injection, and staying well hydrated. Most early side effects are mild and settle within a few weeks as your body adjusts.

How quickly will you start seeing results?

It helps to separate two things: how quickly the medication starts working, and how quickly you see changes on the scales. Most people notice appetite changes within the first week or two, well before any significant weight loss becomes visible.

Meaningful weight loss tends to build gradually over weeks and months rather than days. In clinical trials, measurable weight loss was seen from around the first month and continued to develop over the following year as the dose increased and the effects compounded. [3] This is a treatment that rewards patience and consistency, not a rapid fix.

Trying to rush the process, or judging your progress by someone else’s timeline, tends to lead to disappointment. Steady, sustainable progress is both more realistic and more durable, and realistic weight loss timelines usually span months rather than weeks.

How to set realistic goals when starting treatment

Setting the right goals from the outset makes a real difference to how you experience treatment. The most useful goals are based on gradual, sustainable progress rather than a race to a particular number, and certainly rather than comparing yourself to before-and-after stories online, which rarely reflect the full picture.

It also helps to remember that medication works best as part of a bigger picture. In the clinical trials behind these treatments, medication was always combined with a reduced-calorie diet and increased physical activity. [3][4] Paying attention to nutrition, movement and sleep tends to support the best and most lasting outcomes, and these habits become easier to build when appetite is more manageable.

Finally, goals are not fixed. They can and should be reviewed with your clinician as treatment progresses, taking into account how you are responding and how you feel. A goal that made sense at the start may sensibly evolve over time.

What support should you expect once you start treatment?

Starting treatment is just the beginning, and good ongoing support matters as much as the initial prescription. With SwiftDoctor, care does not stop once your first prescription is issued. Dose reviews and regular check-ins are built into the service, so your treatment can be adjusted as your body responds.

Just as importantly, having a clinician to speak to in the early weeks is reassuring. If side effects arise, or questions come up as you settle into treatment, you are not left to figure it out alone. This kind of support can make the difference between a smooth start and an unnecessarily difficult one.

The approach is judgement-free from day one, whatever your starting point or reasons for seeking treatment. If you would like to explore your options, you can find out more about our weight loss treatments.

Frequently asked questions

How quickly can I start weight loss injections after a consultation?

For eligible patients, treatment can often begin within days. Because the SwiftDoctor process is completed online, there is no lengthy waiting list, and once a clinician has confirmed treatment is suitable and issued a prescription, medication can be delivered discreetly to your door.

What is the starting dose of Mounjaro or Wegovy?

Mounjaro usually starts at 2.5 mg once weekly for four weeks before increasing to 5 mg if needed, with further increases up to a maximum of 15 mg over time. [1] Wegovy starts at 0.25 mg once weekly and is increased every four weeks if needed to a 2.4 mg maintenance dose. [2] Both start low deliberately, to reduce side effects.

Is it normal to feel sick in the first week of treatment?

Mild nausea is one of the most common early effects and reflects your body adjusting to the medication. [1][2] It is usually mild and tends to settle within a few weeks. Eating smaller meals, avoiding rich foods and staying hydrated can help. If nausea is severe or persistent, speak to your clinician.

How long before I see results after starting treatment?

Most people notice appetite changes within the first week or two, while visible weight loss builds more gradually. In trials, measurable weight loss was seen from around the first month and continued over the following months. [3] Focusing on steady progress rather than rapid change gives the most realistic expectations.

What should I eat when I first start weight loss injections?

There is no single required diet, but smaller, balanced meals tend to be more comfortable in the early weeks, especially if you feel any nausea. Prioritising protein and fibre, staying hydrated, and easing off rich or fatty foods around your injection can all help. Combining treatment with good nutrition also supports better long-term results.

Sources

[1] Electronic Medicines Compendium (eMC), "Mounjaro 2.5 mg solution for injection: Summary of Product Characteristics" (Eli Lilly), https://www.medicines.org.uk/emc/product/15484/smpc

[2] Electronic Medicines Compendium (eMC), "Wegovy 0.25 mg–2.4 mg solution for injection: Summary of Product Characteristics" (Novo Nordisk), https://www.medicines.org.uk/emc/product/13616/smpc

[3] Wilding JPH et al., New England Journal of Medicine, "Once-Weekly Semaglutide in Adults with Overweight or Obesity" (STEP 1), https://doi.org/10.1056/NEJMoa2032183

[4] Jastreboff AM et al., New England Journal of Medicine, "Tirzepatide Once Weekly for the Treatment of Obesity" (SURMOUNT-1), https://doi.org/10.1056/NEJMoa2206038