What are GLP-1 medications?
GLP-1 medications mimic the effects of a naturally occurring hormone released by the body after eating. This hormone plays a role in appetite, digestion and blood sugar regulation.
Some newer medications, such as tirzepatide, work on both GLP-1 and GIP receptors.
For people who have been prescribed them for weight management, these medications can help reduce appetite and help you feel fuller for longer. They are designed to be used alongside healthy nutrition, physical activity and ongoing lifestyle changes.
HOW DO THEY WORK?
BRAIN
Helps regulate appetite and may reduce hunger and cravings.
STOMACH
Slows digestion, helping you feel fuller for longer.
BLOOD SUGAR
Helps regulate blood glucose and supports insulin release when needed.
What about “food noise”?
Many people describe a reduction in “food noise” — persistent thoughts about food, eating or cravings.
GLP-1 medications affect areas involved in appetite and reward, although research into their effects on food reward, cravings and other behaviours is continuing.
WHAT MIGHT YOU NOTICE?
As treatment begins, some people may notice:
✓ Feeling satisfied with smaller portions
✓ Feeling fuller for longer
✓ Reduced hunger
✓ Fewer cravings
✓ Less interest in food between meals
Everyone responds differently, and changes may happen gradually.
COMMON SIDE EFFECTS
Like all medicines, GLP-1 medications can cause side effects, although not everyone experiences them.
Common side effects can include:
Nausea • Vomiting • Diarrhoea • Constipation • Stomach discomfort • Tiredness • Injection-site reactions
Side effects can differ depending on the individual medication and person. If symptoms are troublesome or don’t go away, speak to your prescriber, pharmacist or another healthcare professional.
SEMAGLUTIDE
Semaglutide is a GLP-1 receptor agonist. It mimics the action of the naturally occurring GLP-1 hormone, which is involved in appetite, digestion and blood sugar regulation.
It can help reduce appetite, increase feelings of fullness and slow digestion, making it easier for some people to manage their food intake.
Semaglutide is the active ingredient found in several medicines, but the different brands are licensed for different purposes.
WEGOVY®
Wegovy contains semaglutide and is licensed in the UK for weight loss and weight management in eligible people, alongside dietary changes and increased physical activity.
It works by acting on GLP-1 receptors, including areas of the brain involved in appetite. This can help you feel fuller for longer, experience less hunger and reduce food cravings.
Wegovy is available on prescription, and suitability should be assessed by a healthcare professional.
Good to know: Semaglutide is also sold as Ozempic and Rybelsus, but in the UK these brands are licensed for type 2 diabetes rather than weight management.
MOUNJARO®
Mounjaro is the brand name for tirzepatide.
Unlike semaglutide, which acts on GLP-1 receptors, tirzepatide is a dual GIP and GLP-1 receptor agonist, meaning it works through two hormone pathways involved in appetite and blood sugar regulation.
Mounjaro can help reduce appetite, increase feelings of fullness and slow digestion. It is licensed in the UK for both type 2 diabetes and weight management in eligible people.
It is a prescription-only medicine and should be used alongside appropriate nutrition, physical activity and support from a healthcare professional.
WHAT IS RETATRUTIDE?
Retatrutide is an investigational medication currently being studied for obesity and related metabolic conditions.
Unlike traditional GLP-1 medications that target one hormone receptor, Retatrutide is known as a triple hormone receptor agonist because it acts on three different pathways:
GLP-1 – involved in appetite, fullness and blood sugar regulation
GIP – involved in insulin response and energy balance
Glucagon – involved in energy use and metabolism
Researchers are studying whether targeting all three pathways could provide additional benefits for weight management and metabolic health.
WHAT HAVE THE TRIALS FOUND?
Results so far have been promising- In the original Phase 2 obesity trial, participants receiving the highest studied dose had an average 24.2% reduction in body weight after 48 weeks.
More recently, Lilly reported results from its Phase 3 TRIUMPH-1 trial. Participants receiving 12 mg lost an average 28.3% of their body weight at 80 weeks, while 45.3% achieved weight loss of at least 30%.
SIDE EFFECTS
The most frequently reported side effects in clinical trials have been gastrointestinal, including:
Nausea • Diarrhoea • Vomiting • Constipation
In the Phase 2 trial these were generally mild to moderate, occurred more frequently at higher doses and were particularly common during dose escalation.
IMPORTANT
Retatrutide is still an investigational medicine.
It has not yet received regulatory approval for routine prescribing. Its safety and effectiveness continue to be evaluated in clinical trials.
Nano Tracker provides information about retatrutide for educational purposes only and does not recommend, prescribe or supply investigational medications.
FURTHER READING
New England Journal of Medicine – Retatrutide Phase 2 Trial
IMPORTANT SAFETY INFORMATION
GLP-1 medications are prescription medicines and should only be used when prescribed by an appropriate healthcare professional.
They are not suitable for everyone. Your prescriber should assess your medical history, other medications and individual circumstances before treatment.
GLP-1 medicines should not be used during pregnancy, when trying to become pregnant or while breastfeeding. There are also specific contraception recommendations for people using tirzepatide (Mounjaro).
SEEK URGENT MEDICAL HELP
Severe and persistent abdominal pain, particularly pain that may spread to your back and may be accompanied by nausea or vomiting can be a symptom of acute pancreatitis.
Although uncommon, the MHRA strengthened its warning about this risk in January 2026. Seek urgent medical attention if you experience these symptoms.
YOUR JOURNEY IS MORE THAN A NUMBER
Medication can be one part of the journey. Building habits, understanding your body and recognising patterns can be just as important.
Nano Tracker helps you keep everything together in one place, from nutrition and hydration to symptoms, injection sites, movement and progress, so you can better understand your journey over time.
Track. Learn. Understand your journey.
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DISCLAIMER
The information provided by Nano Tracker is for general educational and informational purposes only and should not be considered medical advice.
Nano Tracker does not diagnose, prescribe or recommend changes to medication or treatment.
Always follow the instructions provided by your prescriber and the patient information leaflet supplied with your medication. Speak to a qualified healthcare professional if you have questions about your treatment, side effects or health.
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SOURCES & FURTHER READING
NHS – Semaglutide information
NHS – Tirzepatide information
MHRA – GLP-1 medicines: what you need to know
NICE – Medicines for managing overweight and obesity
