Zepbound vs Mounjaro in the UK | AJ Hill Aesthetics UK

Mounjaro (Tirzepatide)

What is Zepbound aka Mounjaro aka Tirzepatide?

The well-publicised Semaglutide may be about to get some strong competition. Mounjaro is a weekly self–injectable pen used for weight loss. It contains tirzepatide which works by regulating blood sugar and energy balance levels, helping to reduce appetite and prevent cravings.

How does Mounjaro work?

The active ingredient in Mounjaro is called tirzepatide. Tirzepatide works on two different hormonal receptors: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). You may have heard of GLP-1 from other weight loss injections.

GLP-1 helps to regulate blood sugar levels, which in turn talks to the brain to make you feel less hungry and prevent cravings. It also slows down the emptying of the stomach to keep you feeling fuller for longer.

GIP regulates energy balance in brain and fat cells, enhancing the GLP-1 effect of suppressing your appetite and improving sugar control.

By mimicking the effects of both these naturally occurring hormones, Mounjaro has been shown to have greater weight loss potential than medicines that work on GLP-1 alone.

During clinical trials to evaluate the effectiveness of Tirzepatide when used for treating obesity, participants without diabetes lost on average 52lbs after 16 months - or 22.5 per cent of their weight - compared to those who took the placebo. The highest-dose of the weekly injection, known as tirzepatide (brand name Mounjaro), saw obese adults drop more than a fifth of their bodyweight in little over a year.

The latest study involved 2,539 adults, although none had diabetes

Volunteers given the highest dosage of tirzepatide lost 52lbs after 16 months - or 22.5 per cent of their weight - while those given weaker shots dropped between 35 and 49lbs.

Commenting on the latest study, Professor Sir Stephen O’Rahilly, Director of the Medical Research Council Metabolic Diseases Unit at Cambridge University, said: “The results of this trial are very impressive. Treatment of people with obesity with a weekly injection of tirzepatide produced weight loss similar to that seen with weight loss surgery. Blood tests showed improvements in all the markers of metabolic and cardiovascular health. This study, and recent similar reports of a related agent semaglutide, provide secure evidence that people with obesity can be effectively and safely treated using a medication that is based on the modification of naturally occurring hormones."

How do I use Mounjaro?

Just like Ozempic, Wegovy, Saxenda and Trulicity, you inject Mounjaro under the skin (subcutaneously) in your stomach area, thigh or upper arm once a week using an injection pen. Don’t worry, it’s actually much easier than it sounds and if we prescribe Mounjaro for you, we’ll provide you with full instructions on how to use it. You must follow a strict dosage increase schedule as advised by your healthcare provider.

The pen comes in a self-injectable pre-filled syringe, with a built-in glass vial containing the medication.

After each dose, you will visibly see a grey plunger moving along the glass vial from one end to the other. Please note that whilst the plunger will move towards the end of the glass vial with each dose, it will NOT fully reach the end of the glass vial - there will still be some medication / liquid left at the end of the glass vial, known as priming fluid, after all 4 doses are administered - this is NOT an extra 5th dose and it is present in the vial to ensure the pen is constantly primed prior to each dose being administered (please see picture below of how your pen should look after each dose, following the grooves/markings on the glass chamber):

What dose of Mounjaro would I need?

To allow your body to get used to the medicine and have the best chance for long-term success, you should follow the gently increasing dosage schedule as instructed.

Usually, you’ll start with a dose of 2.5 mg of Mounjaro, which will increase every four weeks (or as advised and if suitable for you) until you reach your maximum maintenance dose of 15mg. If you have previously used Mounjaro within the past 3 months and wish to order a higher dose than the starting dose of 2.5mg, we will require proof of previous usage uploaded via our Health Form or sent to us via email.

Would I be suitable to use Mounjaro?

You shouldn’t use tirzepatide if you’re pregnant, and you should stop taking Mounjaro at least one month before trying to get pregnant.

Mounjaro is not suitable in some medical circumstances, for example if you use some other diabetes medicines, have severe problems with digesting food, or have a history of pancreatitis or thyroid cancer. If you’re allergic to tirzepatide or any of the other ingredients in this weight loss injection treatment, you must not use Mounjaro.

It’s essential that you give us a full medical history and details of any conditions or other medicines you’re taking when you fill out our online questionnaire. This ensures we’re able to prescribe weight loss treatment that’s suitable and safe for you.

As Mounjaro is a new weight loss medicine available in the UK, it has been assigned a black triangle, which means it will be closely monitored for any adverse effects.

Are there any side effects?

Mounjaro can cause some side effects to occur. Very common ones are gastrointestinal in nature: nausea, vomiting, diarrhoea and constipation. These are mainly seen with dose increases, and tend to settle with time.

Other common side effects could include: fatigue, feeling lightheaded, excess wind (flatulence), gallstones, gastroesophageal reflux, injection site reactions, hair loss and hypoglycemia in patients with type 2 diabetes.

In rare cases, there can be serious side effects, such as:

Pancreatitis – if you develop severe abdominal pain, with or without persistent vomiting, this may be a sign of pancreatitis and you need to get medical help immediately.

Anaphylaxis – if you experience difficulty breathing, swelling of the face, lips or tongue and difficulty swallowing, you may be having a severe allergic reaction (anaphylaxis) and you must seek immediate medical help.

Please read the Patient Information Leaflet that comes with your medicine for full details of side effects and how to use Mounjaro.

How would I manage the side effects?

Common Mounjaro side effects should be mild and are likely to lessen or even disappear after your body gets used to the treatment. We understand that it’s still tough to live with these discomforts though and so we’ve put together some tips for managing these where possible:

Make sure to inject yourself with the treatment at the same time and day each week so your body has a regular interval between each dose
Stay hydrated, sipping water and other clear liquids if you’re experiencing nausea, vomiting or diarrhoea. It may also help to eat smaller meals more regularly and avoid anything that smells or tastes too strong
If you’re struggling with constipation, increase your fibre intake, stay well hydrated and try eating small fruits such as prunes, figs or grapes. Make sure you’re also getting regular activity, such as going on short walks
To ease a headache, spend time in a quiet space to relax, take a simple pain relief medicine like paracetamol, drink plenty of water, and try relaxation techniques such as meditation and DIY scalp massage

For more information on managing side effects and what to do if you experience more severe side effects, see our dedicated aftercare page for our customers.

How long until I see results?

Mounjaro should start working straight away, but it could take several weeks until it has a noticeable effect on regulating your blood sugar level and impacting your appetite and eating habits. The first few doses of Mounjaro are all about getting your body used to the medication and helping it adjust so that it can prepare for weight loss as you climb to the mid-to-higher doses. This is a rough month-by-month guide:

Month 1 - Clinical trials have suggested that up to 4% of body weight can be lost within the first 30 days, though everyone is different so it is important to remember that your loss may be more or less than this.

Month 2 - During month 2, studies have shown that from starting Mounjaro, participants can lose up to 6% of body weight.

Month 3 - This is the month where you should be able to start seeing a good result, with studies showing that participants can lose up to 9% of body weight by the end of the third month - however, as mentioned previously, this is individualised and your result may be more or less.

Month 4 - As your healthier habits and new routines start to become the norm, your weight loss has the potential to reach 11% of your starting weight. Your body should now be in the weight loss mode if you have continued to titrate up the doses.

Month 5 - Studies have shown up to 12% of weight loss can be achieved, dependent on dosing and other factors such as diet and exercise. For example, if your starting weight was 90kg, 12% loss would leave you at 79.2kg! That's an amazing 10.8kg (or 1 stone and 10lbs loss!)

Month 6 - Now that you're in the full swing of things, and you may now have reached the top dose, your journey does not end here. We can discuss a Maintenance (longer term) dosing regime and help you achieve your goals for the long run.

Can I switch from other weight loss medications to Mounjaro?

If you’re using Saxenda or Wegovy, you’ll need to wait 7 days before switching to Mounjaro. This is called the 'washout' period, and gives the body time for the first drug to leave the system. All patients using Mounjaro for the first time will start with 2.5mg. Keep in mind, Mounjaro may not be suitable for you (even if you're using another weight loss medicine). We’ll assess if it’s right for you during your consultation.

Which medicine is best?

Wegovy and Mounjaro are both weekly injection pens and work in similar ways to aid weight loss. Mounjaro has proven more effective in clinical trials, as it works on GLP-1 and GIP hormones, whereas Wegovy only works on GLP-1. However, Mounjaro is a new medicine in the UK so we don’t have as much safety data on it compared to other medicines in the long term. Deciding if or which medicine is right for you will depend on different factors, which we’ll assess during your consultation. If you’re already on Wegovy (or Saxenda) and losing weight, we recommend you keep using it. Keep in mind, weight plateaus are normal on your weight loss journey.

What do the results of Mounjaro show?

Tirzepatide has been mentioned in a lot of media articles since 2022. You can find a selection of them below:

Tirzepatide Powers 'Unprecedented' Weight Loss in Obesity Trial (medscape.com)

Tirzepatide new treatment option for people who are overweight or have obesity: SURMOUNT-1 clinical trial (medicaldialogues.in)

Focus On - tirzepatide, semaglutide (thepharmaletter.com)

Diabetes drug leads to notable weight loss in people with obesity – study | Medical research | The Guardian

Diabetes drug could be a game changer for obesity, new study shows (usatoday.com)

Tirzepatide Once Weekly for the Treatment of Obesity | NEJM

Game-changing drug can help Brits shed up to 52lbs, experts say (thesun.co.uk)

Why does UK based Mounjaro 2.5mg say it expires in May 2024?

The current batches of 2.5mg Mounjaro available in the UK have a printed expiry date of 05/2024. This was reviewed by Eli Lilly (the manufacturer) and the MHRA (the Medicines & Healthcare Products Regulatory Agency). The medication was found to be safe & effective to use until September 2024 as the shelf life is longer than initially realised.

Please see the MHRA's official announcement on the extension of the shelf life / expiry date for the 2.5mg Mounjaro:

MHRA Website Link

MHRA / Eli Lilly Official Communication Letter

My Mounjaro pen is stuck - what can I do?

This has been reported by several patients and we have started to see videos online appearing regarding this issue.

The pens can be a little temperamental and there could be several reasons why the pen is not administering a dose.

The following tips have been suggested by a pharmacist;

If the pen's is not turning fully to load your dose (e.g. showing "1" in the dose window):

Before turning/dialling up the dose, give the end of the dial a wiggle / tap on the side.
Whilst turning the dial to get to your dose, tap and wiggle the extendable dose dial as it extends outwards.

If you manage to turn the dose to display "1" in the dose window but the dose will not administer:

Please check the needle is screwed on straight (not at an angle)
Please check both caps have been removed from the needle
If still no administration, please change the needle for a new needle. Sometimes the needles can be occluded and not allow the medication to pass through.

Please also see the video below from a UK based doctor regarding how to fix some of the common faults found with the Mounjaro KwikPen. If you still need assistance, please get in touch with us.

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