Understanding the Side Effects of Weight Loss Injections: A Comprehensive Guide to Common and Uncommon Reactions

Weight loss injections are being talked about everywhere now-a-days, from the news to celebrity gossip pages, from social media to chats in the salon, everyone wants to know what they are and how they work for weight loss.

These injections, also known as “skinny jabs” or “slimming pens”, offer an additional tool to aid in weight loss alongside traditional methods like diet and exercise for those who struggle to lose weight sustainably or effectively.

While they can be effective in achieving weight loss goals, it is crucial to understand the potential side effects that may occur. Weight loss injections should never be an impulse decision, they should be prescribed with care and used in conjunction within fully supported weight loss programmes.

In this comprehensive guide, we will explore what weight loss injections are, how they work, who can use them, and the common and uncommon side effects associated with these injections. We will also provide key considerations to remember when considering weight loss injections and discuss how Bodyline Clinic can support your weight loss journey.

What are weight loss injections?

Weight loss injections are medications that are administered through injections to assist individuals in their weight loss efforts. These injections target specific mechanisms in the body that regulate appetite, metabolism, and fat storage.

By stimulating the release of certain hormones or mimicking their effects, weight loss injections can help suppress appetite, control blood sugar levels, and increase feelings of fullness and satiety. This approach can contribute to successful weight loss by ensuring users stick to a reduced-calorie diet and create a calorie deficit.

How do weight loss injections work?

Weight loss injections administer medications that activate GLP-1 or combined GLP-1 GIP receptors in the body, these medications are known as receptor agonists.

The medications currently available to be prescribed for the treatment of obesity in the UK are:

Tirzepatide mimics the effects of two hormones that are naturally produced in the body, these are glucose-dependent insulinotropic polypeptides (GIP) and glucagon-like-peptides 1 (GLP-1) receptor agonists. Semaglutide and Liraglutide just mimics GLP-1 receptor agonists.

Both GLP-1s and GIPs are released in the gut and help individuals achieve weight loss by addressing multiple aspects of the weight management process.  By mimicking the effects of GLP-1 and GIP, these injections encourage the body to:

  • Stimulate insulin secretion, a hormone that prevents blood sugar levels getting too high
  • Inhibit glucagon secretion, a hormone that prevents blood sugar levels going too low
  • Regulate appetite and food intake

Who can use weight loss injections?

Weight loss injections are typically prescribed to individuals who are living with obesity, have a high body mass index (BMI), or are struggling with weight health related problems such as type-2 diabetes, high blood pressure, and cardiovascular problems.

It is essential to consult with regulated healthcare professionals such as Bodyline who are experienced and specialise in weight management to determine if weight loss injections are suitable for you depending on your medical history, your individual needs, and your weight loss goals.


Contact Bodyline today to find out more about our safe and effective weight loss programmes and range of treatment options.

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Can I use weight loss injections if I am not obese?

Weight loss injections are primarily indicated for individuals who are obese with a BMI of over 30-35.

However, according to guidance from the Medicines and Healthcare products Regulatory Agency (MHRA), some injections may be prescribed to individuals with BMIs classifying them as overweight (higher than 27) who have weight-related health problems.

Dr Morgan Toerien, a weight, health, and wellness practitioner here at Bodyline explained the caution we must take when we may see celebrities and online influencers reaching for them to lose weight, despite not being obese in the first place. 

“With these instances one must be very careful. Everybody has a natural set point for their weight, but if people are using these medications and their set point is in the normal range anyway, then they are creating an environment where there’s too much of those hormones. That breakdown is beyond what is physiologically healthy.”

 “You’ll probably find that people will take them to lose the weight and then stop taking them and the weight will go back on. They’ll end up with that up and down yo-yo effect, which is far less healthy than long term sustainable kind of weight loss. This is especially the case when users are not incorporating diet and exercise, not modifying their lifestyle. But also, if you haven’t really got the amount of weight to lose, you can do a lot of harm to your body by losing too much.”

If you are not obese or overweight with weight health complications and are seeking weight loss injections it is crucial to note that any providers willing to prescribe weight loss injections to you may not be regulated and may be providing unlicensed or black-market medications.

Be sure to read our guide on how to ensure your provider is safe before buying any weight loss injection online, through social media, or through questionable sources.

What are the side effects of Weight Loss Injections: Common and Uncommon

Weight loss injections, like any medication, can have potential side effects, though not everyone will experience these side effects, and their severity may vary from person to person.

Common side effects may include:

Nausea clinical studies identified nausea as the most common side effect, the feeling of wanting to be sick, or your stomach feeling uncomfortable. This should subside as your body gets used to the medication, but if it persists then speak to your prescriber or specialist healthcare provider to discuss options and potential remedies.

Vomiting – like nausea, vomiting should go away on its own as your body gets used to the weight loss injections. However, persistent vomiting should not be ignored, and you should seek assistance from your specialist healthcare provider. Be sure to eat plain, bland foods if you are suffering from vomiting to settle the stomach.

Diarrhoea or constipation – your gastrointestinal system is impacted by the medications, meaning bowel movements can be altered causing either diarrhoea or constipation. This is usually temporary and will subside as your body gets used to the medication, but if this persists in causing issues, seek medical advice from your prescriber or a healthcare professional.

Headaches or dizziness – while rarer than gastrointestinal side effects, some people have reported headaches or dizziness when using weight loss injections, however this generally goes away on its own.

Fatigue – feeling low energy or consistently tired is usually due to other side effects such as vomiting, or if you are not eating enough. This can be improved if you adjust your diet and consume more energy, or when other side effects subside.

Uncommon side effects may include:

Pancreatitis – the swelling of the pancreas, known as acute pancreatitis, is a rare side effect of GLP-1 receptor agonist medications. If you have prolonged pain in the abdomen area with a fever and vomiting, these are signs of pancreatitis, and you should cease the medication and seek medical attention. Most people with drug induced pancreatitis get better within a week.

Gallbladder disease – GLP-1 injections are associated with gallbladder disease because the injections inhibit the gallbladder’s ability to empty. The gallbladder stores bile. While rare, instances of gallbladder disease have been reported, so if you have pain in your abdomen as well as a fever, dark urine, and drops in blood pressure, seek medical attention.

While these side effects are less common, it is crucial to be aware of them and consult with a healthcare professional if you experience any unusual symptoms.

What to remember when thinking about weight loss injections

When considering weight loss injections, it is important to keep the following key points in mind:

1. Consult with a healthcare professional:

Weight loss injections should only be used under the guidance and supervision of a healthcare professional. They will assess your eligibility, provide personalized recommendations, and monitor your progress to ensure safety and effectiveness.

2. Discuss potential side effects:

It is crucial to discuss potential side effects with your healthcare professional. They can provide you with information about common and uncommon reactions and help you understand the benefits and risks associated with weight loss injections.

3. Follow a comprehensive weight management plan:

Weight loss injections should be used as part of a comprehensive weight management plan that includes a balanced diet, regular physical activity, and lifestyle modifications. These injections should be viewed as an aid to support overall weight loss efforts rather than a sole method for achieving weight loss.

4. Choose a reputable provider:

Ensure that you seek weight loss injections from reputable providers who are CQC regulated and have the expertise and expertise in weight management. This will help ensure the legitimacy, safety, and effectiveness of the treatment.

Weight Loss with Bodyline Clinic

At Bodyline Clinic, are CQC regulated we specialise in medically supervised weight loss programmes that incorporate weight loss injections. Our experienced weight health nurses and doctors understand the unique challenges individuals face when it comes to weight loss. We take a personalised approach, assessing specific needs and goals to develop a tailored treatment plan.

Our weight management programmes include comprehensive support and guidance throughout your weight loss journey. We provide ongoing monitoring, dietary guidance, behaviour modification strategies, and lifestyle recommendations to help you achieve sustainable weight loss.

If you are living with obesity and are struggling to lose weight and keep it off, contact us at Bodyline to see if you can make use of our evidence based medical weight loss programmes guaranteed to help with weight loss.   Call 0800 995 6036 or complete a contact form for a call back.

About the author

Picture of Sally-Ann Turner

Sally-Ann Turner

I am the founder and Managing Director of Bodyline. I am passionate about providing tailored medical wellness treatments and industry leading clinical support that really make a positive difference to people’s lives. I am currently working across industry sectors to innovate women’s health solutions that deliver better patient outcomes in peri menopause and menopause.

Find me on LinkedIn

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