Description
What is Mounjaro?
Mounjaro is a prescription-only medication that has been licensed in the UK for weight loss treatment. It is a self-injectable pen containing the active ingredient Tirzepatide. This weight loss injection suppresses appetite and lowers calorie intake.
How does Mounjaro work in the body?
It works by acting on two hormones in the body: GLP-1 and GIP, both of which are released in the gut after eating.
Mounjaro (tirzepatide) mimics the functions of these hormones, and:
- Slows down gastric emptying
- Sends signals of fullness to the brain
- Regulates insulin production
These functions result in less food intake which ultimately leads to weight loss.
What receptors does Mounjaro affect?
Mounjaro (tirzepatide) is a dual-agonist weight loss medication, meaning it binds itself to the cell receptors of two hormones:
- Glucagon-like peptide-1 (GLP-1)
- Glucose-dependent insulinotropic polypeptide (GIP)
GLP-1 controls blood sugar while GIP controls the brain signals that regulate appetite. The combined effect leads to reduced appetite and prolonged feeling of fullness.

Mounjaro KwikPen Summary
| Dose Frequency | Once weekly injection |
|---|---|
| Active Pharmaceutical Ingredient | Tirzepatide |
| Drug Family | GLP-1 and GIP receptors agonist |
| How Mounjaro Works | Mounjaro KwikPen works as an appetite suppressant by mimicking a hormone which makes people feel fuller. Mounjaro also affects metabolism and helps regulate energy balance. |
| Maximum Weight Loss | Up to 20% after 17 months* |
| Available Strengths | 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg & 15mg |
How Effective Is Mounjaro?
Mounjaro is quite effective for weight loss. In clinical trials, people lost up to 20% of their body weight on the highest dose i.e. 15mg within 72 weeks. Most adults (91%) can also expect to lose at least 5% of their body weight when using Mounjaro.
It is more effective than any other GLP-1 weight loss medication. Below is the image demonstrating the results of Mounjaro after 72 weeks of consistent injection.
-16%
-21.4%
-22.5%Note: This information is in accordance with a clinical study comparing a 72-week trial with placebo results.
Mounjaro (KwikPen) Dosage
Use the weekly dose plan below to understand how your Mounjaro injections are taken.
2.5 mg Mounjaro (Starting)
The starting dose of Mounjaro is 2.5 mg. A 2.5 mg prefilled pen costs £210.00 that consists of 4 doses, lasting for 4 weeks.
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5 mg Mounjaro (Continuation Dose)
After the starting dose, the first continuation Mounjaro dose is 5 mg. that consists of 4 doses, lasting for 4 weeks. This pen is used from week 5 to week 8.
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7.5 mg Mounjaro (Continuation Dose)
The second continuation dose of Mounjaro is 7.5 mg. A 7.5 mg pen that consists of 4 doses, lasting for 4 weeks. This pen is used from week 9 to week 12.
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10 mg Mounjaro (Continuation Dose)
The third continuation dose of Mounjaro is 10 mg. A 10 mg pen, that consists of 4 doses, lasting for 4 weeks. This pen is used from week 13 to week 16.
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12.5 mg Mounjaro (Continuation Dose)
The fourth continuation dose of Mounjaro is 12.5 mg. A 12.5 mg, that consists of 4 doses, lasting for 4 weeks. This pen is used from week 17 to week 20.
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15 mg Mounjaro (Maintenance Dose)
The maintenance dose of Mounjaro is 15 mg. A 15 mg pen that consists of 4 doses, lasting for 4 weeks. This pen is used from week 21 onwards, once the body has completely adjusted to the weight loss injection. This dose will continue for the remaining duration of your treatment.
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Mounjaro’s starting dose is 2.5 mg that gradually increases every 4 weeks until the highest dose 15mg is reached. The steady dose increase ensures that the body adjusts to the medicine well.
How To Self-Inject Mounjaro (KwikPen)?
Mounjaro (tirzepatide) is a self-injectable prescription weight loss medication. The Mounjaro pen uses a fine, low-pain needle and requires no manual medication push. To inject Mounjaro, press down on the dose knob until the dose window shows a 0, indicating the dose has been fully administered. Slowly pull the needle out of your skin.
Video Guide On How To Use The Mounjaro Pen (KwikPen) For Weight Loss
Watch this step-by-step video instructions on how to use the Mounjaro injection for weight loss. The video shows complete instructions for using the Mounjaro (tirzepatide) injection.
Where To Inject The Mounjaro Pen (KwikPen)
(Once a week on the same day)
Choose an area: Abdomen or thighs
Select a site for administering the injection.
Make four divisions on the site. Inject into one division per week.
When injecting into the abdomen ensure a 5 cm distance from the navel.
Who can use Mounjaro?
Mounjaro may be suitable for adults who have a BMI of 30 or higher, or a BMI of 27 or higher when they also have weight-related health conditions such as high blood pressure, pre-diabetes, high cholesterol or heart disease.
Can I use Mounjaro for Long-term?
The use of Mounjaro for weight loss varies based on individual health needs, treatment goals, and how well your body responds. For some, long-term use may be recommended to maintain weight loss or support ongoing blood sugar control. Others may be able to discontinue treatment once a healthy and stable weight is achieved.
How often should Mounjaro be taken?
Mounjaro is a once-weekly prescription weight loss treatment. The medication can be taken at any time of day, with or without food, as long as you follow a consistent schedule.
What happens if you miss a dose?
If you miss a dose, take it as soon as possible within four days of the missed injection. If more than four days have passed, skip the missed dose and resume your regular schedule. Maintaining consistency helps ensure the medication works effectively over time.
If you need to change the day of the week you take Mounjaro, make sure to leave at least 72 hours (3 days) between your last dose and the new schedule. After that, continue taking it once a week on the new day.
What happens if you stop the weight loss treatment Mounjaro?
After stopping Mounjaro weight loss treatment, you may notice a return in appetite, so you may not feel full as quickly after meals. This can make it easier to eat more than you did while on Mounjaro, which could lead to weight gain.
Continuing healthy habits, such as balanced nutrition and regular physical activity, can help maintain your weight after stopping the weight loss treatment Mounjaro.
What are the Mounjaro side effects?
After starting Mounjaro weight loss treatment, you may notice some side effects initially. The side effects usually go away once the body gets adjusted to the medication.

Refer to the Patient Information Leaflet for the complete list of side effects.
How to store Mounjaro at home?
You need to store Mounjaro injections in the refrigerator at a temperature between 2°C and 8°C, but never frozen. After removing them from the fridge, they can be kept at room temperature below 30°C for up to 21 days if needed.
Keep your pens in their original packaging to protect them from light, and always check the expiry date before use. Used pens and needles should be disposed of safely.
If you’re travelling, store your pens in a cool, insulated container and avoid exposing them to heat or direct sunlight.
What are Mounjaro warnings and risks?
Mounjaro has some safety points to be aware of, just like any prescription treatment. It should not be used if you have an allergy to tirzepatide or any of the ingredients in the pen.
Most people use Mounjaro without serious problems, but a small number of users may experience certain health issues. These are possible risks and do not affect everyone. They include:
- Pancreatitis (inflammation of the pancreas)
- Stomach-related symptoms, including slower stomach emptying
- Gallstones
- Allergic reactions in rare cases
- Digestive discomfort
- Low blood sugar, especially if taken with insulin or other diabetes medicines
If you ever notice anything unusual while using Mounjaro, it’s best to contact a healthcare professional for advice. Your clinician will review your medical history during the consultation to ensure Mounjaro is safe and suitable for you.
Mounjaro interactions with other medications
Mounjaro can increase the risk of hypoglycemia if taken alongside sulfonylureas, insulin, or other diabetes treatments. Therefore, our medical online consultation form asks about all prescription medications, over-the-counter drugs, or herbal supplements you are taking before starting Mounjaro for weight loss.
What if I cannot afford Mounjaro anymore? Are there any other alternatives?
The recent Mounjaro price hike may make it difficult for many patients to continue with the weight loss treatment. In that case, patients may switch to other alternatives.
All returning and new customers who wish to make a switch need to fill out our online consultation form that will be reviewed by one of our prescribers to check if switching to a new weight loss treatment is suitable for you.
- Wegovy: Once-weekly self-injectable weight loss treatment containing semaglutide. It mimics the hormone GLP-1, regulating blood sugar and appetite. The dose is gradually increased to a maintenance level of 2.4 mg. On average, people taking the maintenance dose can lose up to 10-15% of their starting body weight. Results may vary from person to person, depending on how well the body adjusts to the medication.
- Saxenda: Once-daily self-injectable weight loss treatment containing the active ingredient liraglutide. It is also a GLP-1 medication. The dose gradually increased over several weeks to reach a maintenance level, usually 3.0 mg daily. On average, it helps people to lose up to 10% of their body weight. Results can be different for everyone considering the different tolerance levels and health conditions. (Saxenda is currently unavailable due to the on-going high demand).
Where to buy Mounjaro in the UK?
You can order Mounjaro weight loss treatment through London Slimming Clinic by completing our free online consultation form, providing your medical information and medical history. Our UK-licensed prescribers will review your information to determine whether Mounjaro is safe and suitable for you. If approved, they will issue a prescription, after which your medication will be dispensed through a GPhC-regulated pharmacy and delivered to you discreetly at your provided address.
References & Guidelines:
- https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01200-X/abstract
- https://www.medicines.org.uk/emc/files/usermanual.15484.pdf/
- https://www.england.nhs.uk/ourwork/prevention/obesity/medicines-for-obesity/weight-management-injections/
- https://www.gov.uk/government/news/mhra-authorises-diabetes-drug-mounjaro-tirzepatide-for-weight-management-and-weight-loss
- https://pubmed.ncbi.nlm.nih.gov/35658024/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC4119845/
- https://clinicaltrials.gov/study/NCT04184622/
- https://www.medicines.org.uk/emc/files/pil.15482.pdf/















Ryker (verified owner) –
The overall experience was smooth, supportive, and effective—I highly recommend this store for anyone considering Mounjaro post-consultation with the doctor.
Zohar (verified owner) –
Delivery was fast and the product was exactly as described which gave me confidence to reorder after 3 months of use,
Max (verified owner) –
I was impressed with how quickly my order arrived and the discreet packaging gave me peace of mind after 3 months of use,
Camden (verified owner) –
Prices are fair compared to other online pharmacies and the quality of the medication is outstanding after 3 months of use,
Alan (verified owner) –
Delivery was fast and the product was exactly as described which gave me confidence to reorder after 3 months of use,
Hayden (verified owner) –
Prices are fair compared to other online pharmacies and the quality of the medication is outstanding after 3 months of use,
Mateo (verified owner) –
Delivery was fast and the product was exactly as described which gave me confidence to reorder after 3 months of use,
Owen (verified owner) –
I was impressed with how quickly my order arrived and the discreet packaging gave me peace of mind after 3 months of use,
Richard (verified owner) –
I felt confident knowing my prescription was reviewed by UK-licensed clinicians before approval post-consultation with the doctor,