Medical
Managing Side Effects of Weight Loss Medications

What we’ll cover:

  • Common side effects you might notice
  • Tips to help manage symptoms
  • When to seek urgent support from a professional 

Injectable and oral weight management medications can be helpful in supporting weight loss and improving health. Some weight loss medications can also help reduce blood sugar in people with type 2 diabetes (T2D). However, like most medications, they can also have potential side effects. 

Common side effects of weight management medications

Some side effects are common, others are very rare. Many people experience mild symptoms when starting a treatment or when their dose increases. This can feel worrying, but many side effects improve as your body gets used to the medication. This is one reason your treatment often starts at a lower dose and increases gradually over time. 

Your prescriber has recommended this medication because they believe the benefits are greater than the possible risks for you. They are here to support you, so please let them know if symptoms are affecting you. 

Some common side effects include:

Very common (more than 1 in 10 people experience):

  • Feeling sick (nausea) 
  • Diarrhoea or constipation
  • Headache
  • Reduced appetite
  • If you have type 2 diabetes and take insulin or some other diabetes medicines, low blood sugar can sometimes happen. Symptoms can include:
  • Feeling shaky
  • Sweating
  • Looking pale
  • Feeling hungry
  • Feeling anxious
  • A racing heartbeat (palpitations)

Common (up to 1 in 10 people experience):

  • Being sick (vomiting)
  • Indigestion, bloating or wind
  • Mild stomach pain
  • Feeling dizzy or light headed
  • Sulphur burps
  • Headache or fatigue
  • Worsening of existing diabetes-related vision problems

You can find a full list of side effects in the Patient Information Leaflet that comes with your medicine. 

Tips to help manage side effects

Some small changes can sometimes make symptoms easier to manage:

  • Avoid rich, fatty or spicy foods if they trigger symptoms 
  • Eat smaller meals rather than large portions , try to avoid long gaps between meals
  • Include fibre from foods like fruit, vegetables and wholegrains where you can, and increase these foods gradually
  • Drink plenty of fluids - aim for 2.5 litres of water daily
  • If you are living with T2D make sure to attend your routine eye examinations and discuss low blood sugar management with your prescriber. 

Managing nausea:

Nausea (feeling sick) is one of the most common side effects, especially when starting medication or increasing your dose.

In addition to the tips above, you may find it helpful to choose simple foods that feel easier to tolerate, such as toast, rice or crackers. Try eating small amounts regularly, as having an empty stomach can sometimes make nausea feel worse. 

If you are having heartburn along with nausea, over-the-counter remedies such as Gaviscon may help. Speak with your prescriber, if symptoms are severe, persistent, or affecting your ability to eat and drink. 

Managing sulphur burps:

Sulphur burps can happen for some people particularly when starting the medication. They often improve over time. As well as the above tips, it might be helpful to limit fizzy drinks and alcohol. Try eating smaller meals and chewing thoroughly. 

When to seek urgent medical help

Stop taking the medication and seek urgent medical  advice if you have:

  • A rash, itching, swelling or a change to your breathing 
  • Severe stomach pain, especially if it does not go away
  • Severe or ongoing vomiting
  • Significant and ongoing symptoms that you cannot manage

These symptoms could be a sign of a more serious problem and should be checked quickly by a medical professional.

Summary

Side effects can happen with weight management medications, but they are often mild and improve over time. Small changes to how and what you eat can sometimes make symptoms easier to manage.

If any side effects are causing you concern, speak with your prescriber. They are here to support you.

July 16, 2026
Page last reviewed:
July 16, 2026
Next review due:
Written by
Emelia Judge
Reviewed by
Catherine Hyatt
adattamento a cura del

The information on this page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional for personalised medical guidance.

References

  1. National Institute for Health and Care Excellence (NICE). Obesity: identification, assessment and management [Internet]. London: NICE; 2025 [cited 2026 May 22]. Available from: https://www.nice.org.uk/guidance/cg189
  2. National Institute for Health and Care Excellence (NICE). Tirzepatide for managing overweight and obesity [Internet]. London: NICE; 2024 [cited 2026 May 22]. Available from: https://www.nice.org.uk/guidance/ta1026
  3. Electronic Medicines Compendium (emc). Wegovy (semaglutide) Summary of Product Characteristics [Internet]. Datapharm Ltd; 2026 [cited 2026 May 22]. Available from: https://www.medicines.org.uk/emc/product/13799/smpc
  4. Electronic Medicines Compendium (emc). Mounjaro (tirzepatide) Summary of Product Characteristics [Internet]. Datapharm Ltd; 2026 [cited 2026 May 22]. Available from: https://www.medicines.org.uk/emc/product/15484/smpc
  5. NHS. Low blood sugar (hypoglycaemia) [Internet]. London: NHS; 2024 [cited 2026 May 22]. Available from: https://www.nhs.uk/conditions/low-blood-sugar-hypoglycaemia/
  6. [4] GOV.UK. First GLP-1 tablet for weight loss approved in the UK [Internet]. London: Medicines and Healthcare products Regulatory Agency; 2026 [cited 2026 Jul 8]. Available from: https://www.gov.uk/government/news/first-glp-1-tablet-for-weight-loss-approved-in-the-uk
  7. [5] Electronic Medicines Compendium (emc). Rybelsus (semaglutide tablets) Patient Information Leaflet [Internet]. Datapharm Ltd; 2026 [cited 2026 Jul 8]. Available from: https://www.medicines.org.uk/emc/product/14389/pil

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