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Find answers to some of the most frequently asked questions about the SemaPen programme

Our Programme

Why choose the SemaPen Programme?

Most companies supplying Wegovy and Mounjaro online are pharmacy businesses.
We are different.

The SemaPen team is made up of trained weight management clinicians, not pharmacists supported by a GP or a dietician.

This gives you access to a multi-disciplinary team of weight management experts – doctors, psychologists, dieticians, and specialist nurses who have been helping patients achieve their weight loss goals for more than 20 years.

Unlike others, we can assess and signpost patients to a full range of treatments, from bariatric surgery through to weight loss pens like Wegovy or Mounjaro plus supportive care, psychological and dietary advice.

We believe this provides clients with an unrivalled level of assistance that’s delivered by real experts.

The SemaPen programme combines the latest and most effective medications with real-time monitoring using cloud-linked smart scales we supply as part of the programme. You don’t even have to remember to let us know – we are able to check if things are going well and intervene with helpful advice if they’re not.

You can contact us 24/7 online without the need to book appointments or online consultations. With great support from experts, our unique digital platform will help you reach your health goals.

Am I suitable for the SemaPen programme?

Wegovy (semaglutide) and Mounjaro (tirezepatide) are approved for use in adults with a BMI of 30 or higher, although there are certain medical conditions that would make treatment inadvisable.

This BMI cut-off is lowered to 27  for those who also have at least one weight-related condition.  Some examples include high blood pressure, type 2 diabetes, high cholesterol, sleep apnoea, gastro-oesophageal reflux, weight-related depression, or joint pain.  We will ask you about this as part of the onboarding process.

People of certain ethnic origins (Asian, Black Afro-Caribbean, Arabs) are more prone to developing type 2 diabetes and cardiovascular complications of obesity at lower BMIs than Caucasians and this may be taken into account when deciding if you are suitable for treatment with Wegovy or Mounjaro.

Complete our free, online medical questionnaire to determine whether you are suitable for the SemaPen programme.

Why do Wegovy or Mounjaro have to be given as an injection?

The active drug in Wegovy is semaglutide which is available to treat obesity in both tablet form (Rybelsus) and as an injection (Wegovy). The problem is that the results with the tablet are currently not nearly as good as when semaglutide is injected.

Mounjaro (tirezepatide) is also self-administered at home once a week. We’ll provide you with all of the equipment you need to do this, including ultra-fine needles and a sharps bin.

The injections are given just under the skin in the abdomen, arm, or upper thigh. You don’t have to be a doctor or a nurse to do this. We have a great weight loss injection training video by our nurse, Davina, that you can find here.

What is the difference between Ozempic and Wegovy?

Semaglutide has two main benefits. One is that it helps bring diabetes under control. The other is that it causes weight loss (especially at higher doses). The manufacturers of semaglutide obtained two separate licenses, one for each kind of treatment. Semaglutide used to treat diabetes is branded Ozempic, but when it is used under a license to treat obesity, it is branded Wegovy.

Whilst both Ozempic and Wegovy contain the same active ingredient, semaglutide, Ozempic is not available at the higher 1.7mg and 2.4mg doses that have been shown to be the most effective doses for weight loss.

At SemaPen, we made a conscious decision not to offer Ozempic for weight loss, and we felt this was unethical profiteering, which predictably led to a shortage of the drug for patients who needed it to treat their diabetes.

What is the difference between Wegovy and Mounjaro?

Wegovy is designed to mimic a single hormone in the body (GLP-1), while Mounjaro does a dual job by mimicking two hormones (GLP-1 and GIP) that help with blood glucose levels and weight loss. Despite their different approaches, both medications are administered once a week.

How do I get in touch with you? Can I get to speak to a SemaPen expert face to face?

Yes.  The SemaPen app gives you access to our specialists using SMS, WhatsApp, and an online chat function. We are automatically alerted by our system if things are not going according to plan and will reach out to you with help.

However, if you feel you need some extra support with your diet or your relationship with food and would value a confidential 30-minute one-to-one online consultation with one of our dieticians or psychologists, we can also set this up for you. These face-to-face private consultations are chargeable and can be booked through your personal dashboard on the SemaPen app.

Why is it necessary to stay on the treatment for 12 months?

The weight loss injections will start to work within a week of starting treatment, so you may be tempted to think it would be OK to take it for just a few months and then stop. This is a bad idea for three reasons.

1. You will not have benefited from the most powerful effects of the treatment, because you’ll still be on a weaker pen.
2. You will almost certainly regain some of the weight you’d lost, and quite quickly.
3. You probably won’t have your head in the right mindset that acknowledges the need for lifestyle change to achieve a durable, long-term result. This is crucial.

Try not to think of the treatment as a short-term quick fix, but more of a means to help you improve your long-term emotional and physical well-being.

Can I spread the cost of treatment?


We only ask you to pay 1 month at a time, so this helps spread the cost of the 12-month course of treatment.

And remember, you can cancel at any time if you feel the SemaPen program is not for you.

Are there any charges for early cancellation?

If you cancel your subscription within the first 3 months, we will recover the cost of the Withings smart scales that we supplied to you when you joined the programme, along with a fee (£30) to cover our admin and distribution costs.

If you cancel after 3 months, there are no cancellation charges to pay, and you are free to keep the smart scales.

What happens if I go on holiday? Can I pause my subscription?


You will receive your next weight loss pen automatically about a week before the current pen runs out.
This may enable you to take the new pen on holiday with you and continue your treatment.
We provide you with a travel card that explains to the authorities why you will be carrying needles and the pen.

If you are going away for an extended period (or you wish to stop while you are away), you can pause your subscription by logging into your personal dashboard on the SemaPen app.

When you restart, you can select a lower dose than before to give your body a chance to get used to the medication again.

Tell me about the Money-Back Guarantee

We are so confident that the treatment will help you that we are prepared to offer refunds to people who complete the 12-month SemaPen Program and who do not lose at least 5% of their starting body weight.

To qualify for a refund, you need to have demonstrated that you have engaged with the programme (for example, by registering the smart scales and using them regularly), that you have responded to the advice our support team gave when they interacted with you; and that you have followed the monthly treatment schedule without any gaps in treatment. The amount refunded will be proportionate to how much weight loss you achieved. Full details can be found in our T&Cs.

Can people with diabetes go on the SemaPen Programme?

Yes, but some special precautions are needed for patients taking insulin, sulphonylureas, and DPP4 inhibitors (see below).

The main worry is the risk of severe low blood sugar (hypoglycaemia) when the drug is taken together with other diabetes treatments that reduce blood sugar, such as insulin, sulphonylureas (e.g., gliclazide and glipizide) or another GLP1 agonist with a similar action to Wegovy/Mounjaro. Unpredictable low blood sugars could risk injury through falls and make daily activities such as driving or operating machinery hazardous. For this reason, we currently do not allow patients on insulin or sulphonylureas to join the SemaPen programme.

Another class of diabetes drugs known as DPP4-inhibitors (these drugs usually end in ‘gliptin’) work by preventing the breakdown of GLP1, so concurrent use with Wegovy or Mounjaro is not recommended.

If you want to join the SemaPen programme and are taking a DPP4 inhibitor, please ask your GP or diabetes nurse to stop it, and put you on a safe alternative such as metformin, if possible.

Is the SemaPen Programme suitable for teenagers and adolescents?

The SemaPen Program is currently not available to people under the age of 18, but this is a service we hope to introduce in the future.

We believe there is a real need for effective intervention to help young people who are living with obesity.
Clinical trials show that semaglutide used in combination with lifestyle intervention is a safe and effective treatment in adolescents aged 12 to <18 with a BMI above the 85th percentile and at least one weight-related medical condition [6].

Those taking semaglutide for a year lost 12 cm more off their waistline and almost 17% more bodyweight than others who received lifestyle intervention and a placebo (dummy) injection.

[6] Weghuber D et al (2022) “Once-weekly semaglutide in adolescents with obesity” New England Journal of Medicine

Can I get Wegovy on the NHS?

Wegovy and Mounjaro have been approved for use on the NHS but few centres are currently able to prescribe it, whilst decisions are awaited about how it will be delivered and funded.

Furthermore, NICE has advised that NHS patients must have a BMI greater than 35 and at least one weight-related medical condition such as type 2 diabetes [5]. It is only under exceptional circumstances that the NHS will prescribe weight loss injections to people with a BMI of 30-35, even if they do have medical conditions.

These criteria are significantly stricter than those possible under the Wegovy and Mounjaro licenses, which allow self-funded treatment for patients with a BMI as low as 27- 30.


How long will it take for me to receive my weight loss pen and scales?

Your medication should arrive within 1-3 working days from placing the order.

Your scales are expected to ship within 1-3 working days of your order being placed.


What should I do if my scales or medication don’t arrive, or if they arrive damaged?

When you complete the onboarding process, we arrange for the digital scales manufacturer to ship directly to you and for medication to be dispensed and shipped to you via our pharmacy partner, who in turn arranges delivery with a courier.  In the unlikely event of a prolonged delay in delivery, loss of items, or transit damage to your order, please contact our Customer Services Department immediately using the SemaPen app and we will arrange for replacements to be issued if the courier is at fault.

Please note that failure to take delivery of goods we send you or providing incorrect delivery details may result in a loss of goods without a refund entitlement.


How much weight am I likely to lose?

A 15% reduction in starting weight after 12 months was seen in a major research study of people who increased physical activity (150 minutes of walking a week), reduced their food intake by 500 kcal a day, and took Wegovy for a year [1].

In a similar trial, people who took Mounjaro saw weight loss of over 21%, although Mounjaro was also associated with transient hair thinning and reduced efficacy of the contraceptive pill. [2]

Remember, 15- 21% weight loss was the average outcome (see lost more, and some less) using medication in combination with a closely monitored support programme.

This is why the 12-month SemaPen programme gives you a much better chance of success than just buying the injections without a proper support.

[1] Wilding, J.P.H. et al. (2021) “Once-weekly semaglutide in adults with overweight or obesity,” New England Journal of Medicine, 384(11)

[2] Tirzepatide Once Weekly for the Treatment of Obesity | NEJM

What happens when the medication is stopped?

Weight regain is common.

Clinical studies show that if Wegovy is taken for 12 months and then stopped, a year later people have regained 2/3 of the weight they’d lost on the treatment [3].

The implication of this is that because obesity is a chronic condition, Wegovy and Mounjaro will need to be taken long-term, just like any other treatment for chronic conditions like arthritis.
We will discuss cost-effective solutions to continue on the medications and minimise weight regain with you towards the end of your SemaPen programme.


[3] Wilding JH et al (2022) “Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension”, Diabetes, Obesity and Metabolism (24).

I've heard weight loss injections don't work as well if you have diabetes - is that right?

Unfortunately, that’s correct.

The major clinical trials proving the value of semaglutide [1] and tirzepatide [2] for weight loss did not include any patients with diabetes.
Other studies looking at how the drugs worked in those with diabetes still showed good weight loss, but less than that seen in patients without diabetes  [4].

[4] Davies M et al (2021), “Semaglutide 2.4mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2)” The Lancet (397)

How does Mounjaro make you lose weight?

See ‘How does Wegovy make you lose weight?’

Like Wegovy, Mounjaro also promotes the beneficial effects of GLP-1, but it also promotes the action of a second hormone called GIP.

This gives an extra boost to weight loss, but GIP also tends to counteract nausea, which is a common side effect observed when taking GLP-1 -like drugs.

How does Wegovy make you lose weight?

Wegovy (semaglutide) is almost (94%) identical to GLP1, a natural hormone that is released by the body after eating.

GLP1 is one of several hormones that regulate food intake and appetite – the body’s way of stopping us from putting on too much weight.

In today’s fast-food, less physically active environment, it’s easy to see how this natural defense against obesity can be overwhelmed.

By mimicking the effect of GLP1, Wegovy targets a specific region in the brain responsible for appetite control, reducing feelings of hunger. It also slows stomach emptying, which makes you feel full for longer because you are full! Furthermore, Wegovy has beneficial effects on blood sugar and insulin levels, which also help control the desire to eat.

So it’s no surprise that people taking Wegovy find it much easier to decrease their calorie intake by reducing portion size and eating less often.


My Mounjaro Pen has an expiry of May-2024, can I still use it?

Yes, the shelf life of Mounjaro® 2.5mg KwikPen® has been extended from 9 months to 14 months based on new stability data. This extension was approved by the MHRA on March 25, 2024. Therefore, your Mounjaro® 2.5mg KwikPen®, which has a printed expiration date of 05-2024 on the carton and pen, can now be used until October 2024. 

Will I lose all enjoyment of food if I take weight loss injections?

Absolutely Not!

The treatments don’t alter the taste of food, they work by suppressing your appetite.  You will also start to feel full much sooner than normal. This dual action makes it much easier for you to avoid snacking and to control the size of your main meals.

You can still enjoy the pleasure of lovely food, but the injections put you in control, so you can moderate your calorie intake.

Do weight loss injections have side-effects?

Like all medications, Wegovy and Mounjaro may cause side effects.

The most common include nausea, bloating, and constipation (occasionally accompanied by abdominal cramps).
This is because one of the ways Wegovy and Mounjaro help is by slowing down how fast the stomach and intestine empty, which contributes to a sense of early and prolonged fullness after meals.

Persistent vomiting can lead to dehydration. It’s usually the result of not using the weight loss injections properly, either by rushing up to a higher dose pen too quickly or by overeating despite the sensation of fullness the drug induces. It’s really important to avoid this.

Side effects are typically worse when starting treatment and for the first few days after moving up to a higher dose pen.
Provided that the strength of each pen is gradually increased, most people (>95%) find side effects fairly easy to tolerate, particularly as they tend to improve over time.

However if they persist it’s important to seek medical advice.

What other side effects that have been reported?

The following information will give you some idea of how much more frequently certain side effects were reported during Wegovy and Mounjaro treatment (compared with patients taking a dummy injection) [1][2]:


Serious Adverse Events 3%
Adverse Events leading to discontinuation of Wegovy 4%
Fatal Events 0%

Nausea 27%
Vomiting 18%
Diarrhoea 16%
Constipation 14%
Indigestion 7%
Abdominal pain 4%
Headache 3%
In patients with type 2 diabetes (only) new or worsening diabetic retinopathy (vision problem) 1.3%

Gallstones 1%
Acute Pancreatitis 0.2%
Cancer 0%
Allergic/Injection Site Reactions 0% (more common with dummy injection)
Low blood sugar 0% (more common with dummy injection)
Kidney, heart and liver disorders 0% (all more common with dummy injection)

Gastroparesis; this is unusually slow emptying of the stomach that can be associated with excess vomiting has been noted in a very small number of patients taking Semaglutide, but it has not been possible to estimate how much of a risk this is or establish a causal risk between the condition and medication.


Serious Adverse Events 0.1%
Adverse Events leading to discontinuation of Mounjaro 4.5%
Fatal Events 0%

Nausea 21.5%
Vomiting 10%
Diarrhoea 14%
Constipation 11%
Indigestion 6%
Abdominal pain 2%
Headache 0%

Alopecia 4%
In patients with type 2 diabetes (only) new or worsening diabetic retinopathy (vision problem) >1%

Gallstones 0.5%
Acute Pancreatitis 0%
Cancer 0%
Allergic/Injection Site Reactions 4.5%
Low blood sugar 1% (more common with dummy injection)
Kidney, heart and liver disorders 0.3% (all more common with dummy injection)

Gastroparesis 2%

Suicidal Ideation 0.3%

What are the risks of weight loss injections in pregnancy or if I'm breastfeeding?

Weight loss injections should not be used in pregnancy.

Rapid weight loss could be linked to poor fetal development and, possibly, an increased risk of miscarriage.

The safest advice is that all women of childbearing potential should use contraception when treated with Wegovy or Mounjaro.

There is also evidence that using Mounjaro can reduce the efficacy of oral contraceptive pills, so you are encouraged to consider alternatives.

If pregnancy does occur, you must stop Wegovy/Mounjaro immediately.

If you wish to become pregnant, discontinue Wegovy/Mounjaro at least 2 months before planned conception.

Semaglutide was excreted in milk so to reduce any possible risk to your infant, do not take Wegovy/Mounjaro if you are breast-feeding.

Do weight loss injections cause cancer?

This is a bit of an urban myth.

Since semaglutide was approved in the USA in 2017, there has never been a single case of cancer reported in humans that was thought to be related to taking the treatment.

The hype comes from studies in rats that showed a risk of a rare kind of non-lethal thyroid tumour (C-cell tumour), something to which rats are particularly susceptible when taking GLP-1 drugs.
No other types of tumours were noted.

The relevance to humans is thought to be low, but to err on the side of safety, we don’t allow people with a history of thyroid cancer (particularly some rare hereditary forms of thyroid cancer) to join the SemaPen programme.

Can I take Wegovy if I have diabetes?


Many patients with type 2 diabetes are already treated with semaglutide (under its other name, Ozempic) or tirezepatide (Mounjaro)

However, there are some special considerations we need to take into account before prescribing Wegovy or Mounjaro for weight loss in patients with diabetes.

1. Certain drugs:
If you are on insulin or a sulphonylurea (eg gliclazide), there is an increased risk of severe hypoglycemia (low blood sugar) when used in combination with Wegovy/Mounjaro.
At present, we do not accept patients on these medications into the SemaPen programme, but we will keep this decision under review.

2. Vision problems:
In patients with type 2 diabetes, new or worsening diabetic retinopathy (vision problems) was more likely to occur in patients taking Wegovy (up 1.3% compared with placebo). It is not certain that this is a direct side effect of Wegovy, nevertheless, we recommend a diabetic eye check before starting Wegovy and every 6 months afterward.

3. Using two GLP1 agonists at the same time:
You should not use Wegovy or Mounjaro for weight loss in conjunction with any other drug of a similar class that is being used for weight loss or to treat your diabetes.
These include Victoza, Trulicity, Ozempic, Saxenda, Rybelsus, Byetta, and Bydurion.

I've heard weight loss injections might affect mental health. Is this true?

A small number of case reports in Iceland and the USA have raised the question of whether there is a potential link between the use of GLP-1 agonists and thoughts of self-harm.  At the time of writing, the number of reports is tiny compared with the number of people treated with Wegovy and Mounjaro, and no causal association has been demonstrated.

We will monitor your mental health during your time on the SemaPen programme using special self-assessment questionnaires. In the unlikely event that you experience any suicidal thoughts while on treatment, our advice is to stop treatment and seek urgent help from your family doctor or mental health practitioner.

Can I take other medications alongside weight loss injections?

Yes, although see FAQ above about diabetes medications.

Clinical studies have shown no other relevant drug interactions with Wegovy, although Mounjaro has been found to reduce the efficacy of the oral contraceptive pill.

How dangerous would it be for someone with an eating disorder to take weight loss injections?

A past or current history of eating disorders such as anorexia or bulimia is an absolute contraindication to using Wegovy/Mounjaro.
It could lead to significant malnutrition and even death.

For this reason we ask all potential SemaPen patients to formally confirm:

  1. That they do not have a history of an eating disorder
  2. That the information they have provided regarding height and weight is accurate
  3. Their age and identity using a biometric ID check cross-referenced to photo ID
  4. Their GP contact details so that we can check whether the GP has any concerns about the patient starting weight loss injections.

We also have a policy whereby failure to

  1. Provide GP details
  2. Register the smart scales provided and repeated failure (after prompting) to record regular weight readings

will result in suspension of your account within 3 months with no further medication issued.

Finally, our algorithms can detect excessive weight loss which will trigger one of our team reaching out to assess and provide support.

Whilst it is impossible to completely prevent an individual from circumventing these measures, we hope these processes will minimise that risk and alert people to the dangers.

If I experience any unusual side effects how do I report this?

As with any new medication, it’s important that regulatory authorities are made aware of any unexpected or unusual side effects as soon as possible.

Although Wegovy and Mounjaro appear to be extremely safe and have been in widespread use in many countries now, should you notice any unusual side effects please message our team via the SemaPen app or through live chat. You can also self-report side effects using the government’s yellow card scheme here.

Do I need to stop weight loss injections before surgical treatment under an anaesthetic?

This is an area where we don’t yet have clear guidance available, as relatively little evidence exists in the literature beyond case studies.


Before surgery under anaesthetic, patients are usually told not to eat or drink for 12 hours or so. The main concern is aspiration at the start of anaesthesia, due to vomiting or passive reflux of stomach contents back into the mouth or lungs, which could trigger severe breathing difficulties.

We know that GLP-1 injections like Wegovy and Mounjaro slow gastric emptying, so the question is whether this increases the risk of aspiration under anaesthesia. The short answer is that we don’t know.

In patients taking GLP1 injections for weight loss or diabetes, whilst there is no clear answer at this point, advice from the American College of Anaesthesiologists states that patients should consider stopping the medication 1 week before surgery.

If surgery is planned under local anaesthetic then there is no need to stop Wegovy or Mounjaro beforehand.