Starting a GLP-1 Medicine: A Simple Guide for Patients

Introduction

Starting a new medicine can bring up a few questions, especially when you are not sure what to expect. If you’ve been prescribed a medicine that belongs to the class of GLP-1 RA or GLP and GIP dual RA , this guide is for you.  

In here, we will explain how GLP-1 RA containing  medicines work, what you may notice during the first few weeks, their common side effects, important safety information, and simple ways to support your treatment. 

What Are GLP-1 Medicines?

GLP-1 medications are prescription drugs that mimic the action of the hormone called glucagon-like peptide-1, produced by the gut. This hormone helps decrease appetite, increases the feeling of fullness after eating, and also plays a role in regulating blood sugar levels¹.  

GLP-1 analogue medicines are prescribed by doctors along with diet and exercise to improve blood sugar control. Some are also used to reduce the risk of adverse cardiovascular events (like stroke and heart attack) and for weight loss in people with obesity^1,2. The available drugs include Ozempic and Wegovy (semaglutide), Mounjaro and Zepbound (tirzepatide), etc¹.

How They Work in the Body

GLP-1 drugs help turn down your appetite signal. They slow down the movement of food through the stomach, making you feel full for a longer time, and help your body secrete insulin when blood sugar is high^1,2. Since digestion and appetite are altered, nausea, bloating or changes in bowel habits can also be among the most common side effects after starting the treatment^2,3. 

Take GLP-1 medicines exactly as prescribed by your doctor. Do not increase, reduce, or change the timing of your dose without medical advice, even if you feel the medicine is working too slowly or you experience side effects. 

What to Expect After Starting?

GLP-1 treatment typically starts at a low dose and increases gradually. This process called titration, allows the body to get used to the new drug and helps reduce the gastrointestinal side effects. Gradually escalating the dose minimises the harsh side-effects the patient has to deal with and allows for better long-term compliance. 

The exact schedule depends on the medicine you have been prescribed and your individual treatment plan. Do not copy another person’s dosing schedule or make changes based on advice found online. 

The First Few Weeks

During the first few weeks of treatment, you may experience gastrointestinal side effects as your body adjusts to the medicine. You may also find that you feel nauseous, bloated, constipated, or have diarrhoea⁴. 

These side effects may settle as your body adapts to the medicine and do not necessarily mean that there is anything wrong⁴. GLP-1 medicines work gradually, so their effects may become more noticeable over time rather than immediately. 

If these side effects are persistent, or get worse, it is important to consult your doctor, who can decide if you need any changes in your treatment plan⁴. 

As Your Dose Increases

Some people experience their digestion issues returning after increasing the dose. These usually goes away when the body gets used to the medication^2,3.  But if you feel the symptoms are too severe or they continue for a long time, contact your doctor². Never self-adjust your dose.  

Your doctor may decide to keep you on a dose for longer, adjust the pace of dose change or recommend other ways to manage symptoms. The effect can be different for everyone. It depends on which medication you get, how big the dose is, what other medication you take and your general condition⁴. 

Understanding Side Effects 

Most common side effects are linked to how these medicines affect appetite and digestion. Because GLP-1 medicines slow stomach emptying and can change how much you eat, digestive symptoms are particularly common, especially when treatment starts or the dose increases^2,3.

Common, Usually Mild Symptoms

These include: 

• Nausea: Slower stomach emptying can make you feel full for longer and may contribute to nausea⁵. 
• Constipation: Changes in food and water intake from reduced gastric emptying can affect bowel movements⁴. 
• Diarrhoea: Changes in digestion can also cause looser or more frequent stools. 
• Bloating: Food remains in the stomach for longer, which can leave you feeling unusually full or bloated¹.
• Fatigue: Eating less than usual, digestive symptoms or changes in blood sugar can sometimes leave you feeling tired or weak⁶. 

These side effects are common with GLP-1 medicines, but you do not have to simply live with them. Talk to your doctor if they bother you, as they may suggest ways to manage them⁷. 

How Your Doctor Helps You Manage Them

Tell your doctor about side effects rather than trying to manage them silently. Your doctor may: 

• Adjust Your Dose: If side effects are difficult to manage, your doctor may slow down dose increases, keep you on the same dose for longer, or adjust your dose. 
• Advise Meal Pattern Adjustment: Depending on your symptoms, your doctor may suggest changes to when and how often you eat⁴.  Eating smaller portions, eating slowly, and avoiding large meals may help reduce digestive symptoms such as nausea and fullness. 
• Recommend Dietary Changes: Your doctor/nutritionist may suggest modifications in your diet such as avoiding spicy and fried food items. If you have constipation, they may advise you to include more fibrous foods in your diet and exclude them in case of diarrhoea. 
• Suggest Improving Hydration: Your doctor may recommend drinking enough fluids, especially if you have vomiting, diarrhoea, or constipation. 
• Review Other medicines: Your doctor may check whether any other medicines you take could be contributing to your symptoms or making them worse and adjust their doses⁸.  

Important Safety Information

Most people can use these medicines safely when they are prescribed and monitored appropriately. However, there are some situations you should inform your doctor about before and during treatment. 

Pregnancy & Contraception

Tell your doctor if you are pregnant, planning a pregnancy or think you may be pregnant. GLP-1 medicines should not be used during pregnancy or while trying to become pregnant. If you are planning a pregnancy, ask your doctor when you should stop your medicine, as the timing can vary between medicines. Usually doctors stop the medicines 2-3 months before allowing you to plan a pregnancy. 

Use reliable contraception while taking a GLP-1 medicine. If you take semaglutide or tirzepatide medicines and use the contraceptive pill, you may need extra protection, such as condoms, for 4 weeks after starting treatment and after each dose increase, as this GLP-1 medicine can interfere with the effectiveness of the contraceptive pill⁹. 

According to some animal studies, tirzepatide is known to pose a risk to the unborn child³. Therefore, it’s important to ask your doctor which contraceptive advice is right for you when you are using GLP-1 medicines. 

Risk of Low Blood Sugar (Hypoglycaemia)

GLP-1 medicines usually do not cause low blood sugar on their own. However, the risk can increase when they are taken with insulin or sulfonylureas, so your doctor may adjust your other diabetes medicines^2,5.  

Symptoms of low blood sugar may include: 

• Shaking or sweating 
• Dizziness, light-headedness, or weakness 
• Hunger 
• Confusion or trouble concentrating 
• Mood Changes, etc^2,3,6

Tell your doctor if you have low blood sugar episodes. Avoid skipping meals, monitor your blood sugar levels regularly and follow your doctor’s instructions. 

Who Shouldn’t Take These Medicines

GLP-1 medicines are generally not prescribed by doctors to people who have: 

• A personal or family history of medullary thyroid cancer 
• Multiple endocrine neoplasia type 2 (MEN 2), a rare inherited condition that can cause certain hormone-producing tumours 
• A previous serious allergic reaction to a GLP-1 medicine or any of its ingredients^2,3.

Make Sure You Have Mentioned the Following to Your Doctor

You should inform your doctor everything about your health because in certain cases, some extra monitoring may be needed with GLP-1 medications. These include: 

• Pancreatitis: Pancreatitis can occur in patients taking GLP-1 medicines. If you have a history of pancreatitis or develop severe or persistent abdominal pain, particularly pain that may spread to your back during treatment, contact your doctor promptly. 
• Gallbladder disease: GLP-1 medicines have been associated with gallbladder problems, and rapid weight loss can increase the risk of gallstones occurrence. Tell your doctor about persistent upper abdominal pain, fever or yellowing of the skin or eyes. 
• Diabetic retinopathy: Sudden improvement in blood sugar can temporarily worsen diabetic retinopathy in some people. If you have diabetic retinopathy, your doctor may recommend closer eye follow-up, especially when blood sugar improves quickly. 
• Kidney disease: Vomiting or diarrhoea can cause dehydration and put extra strain on your kidneys. 
• Taken/taking Insulin or a sulfonylurea: Using these medicines together can increase the risk of hypoglycaemia. Your doctor can adjust the doses accordingly. 
• Gastroparesis or significant digestive problems: As GLP-1 medicines slow stomach emptying, they may not be suitable for people with severe gastroparesis^2,3.
• Surgery or a procedure requiring anaesthesia or deep sedation: Tell your surgeon or doctor if you use GLP-1 medicine. These medicines can slow stomach emptying, which may increase the risk of aspiration (food entering the lungs) during some procedures¹⁰. 

Serious Side Effects-Consult a Doctor Immediately If You Notice Any Serious Warning Signs

The following are some serious side effects that should not be ignored, although they are rare. Contact your doctor immediately and get emergency medical care if you experience: 

• Severe or persistent abdominal pain, particularly if it spreads to your back 
• Repeated vomiting or inability to drink fluids 
• Severe allergic signs such as swelling of the face, lips, tongue or throat, difficulty breathing, rashes, a rapid heartbeat, or other signs 
• Yellowing of your skin or the whites of your eyes, especially with abdominal pain or fever 
• New or sudden changes in vision 
• Symptoms of very low blood sugar such as confusion, severe weakness, difficulty staying awake, trouble concentrating, etc^2,3,6

If any of these symptoms occur, contact your doctor straight away so they can take the next steps. 

Routine Follow-Up & Health Checks

Starting a GLP-1 medicine is not a one-time decision. Your doctor may want to check how you are responding, whether side effects are manageable and whether your dose needs to change. 

Depending on your health and the reason you are taking the medicine, your doctor and care team may monitor things such as: 

• Blood sugar levels 
• Kidney function 
• Symptoms and side effects 
• Eye health if you have diabetic retinopathy^2,3
• Weight and nutrition intake 

Follow your regular appointments and tell your doctor about any changes or new symptoms. Do not change your treatment or try to figure out what’s causing the symptoms by yourselves. Your doctor can review your symptoms and decide what is best for you based on your health and the medicine you take. 

Making the Most of Treatment: Diet & Exercise

GLP-1 medicines are usually prescribed alongside healthy diet and regular physical activity². Since these medicines can reduce your appetite, it’s important to focus on getting enough nutritious food rather than simply eating less. 

Eating Well on a GLP-1

The following can help you with your diet during medication use: 

• Eat smaller meals: Large meals may feel uncomfortable. Start with a smaller portion and eat slowly. 
• Include protein: Choose foods such as eggs, fish, chicken, yoghurt, milk, paneer, tofu, beans, or lentils⁴. 
• Choose nutritious foods: Try to include vegetables, fruits, whole grains, and other nutrient-rich foods¹¹. However, advice should be sought from the doctor in case of severe diarrhoea, as fibre-rich foods can worsen this symptom⁴. 
• Drink enough water: Have fluids regularly, especially if you have vomiting, diarrhoea, or constipation. 
• Limit greasy foods: Fried or high-fat foods may worsen nausea or stomach discomfort for some people. 
• Inform your doctor about poor appetite: If you are eating very little for several days, speak with your doctor or dietitian⁴. 

There is no need to copy someone else’s “GLP-1 diet”. Your doctor might recommend food choices based on your medical conditions and dietary needs. 

Staying Active

Moving your body is crucial during the treatment period. The following are some tips on how to stay physically active: 

• Start with regular light movement: Walking, gentle cycling or other comfortable activities can be a good start. 
• Include strength training: Resistance exercises can help preserve muscle during weight loss. This can include body-weight exercises, resistance bands, or weights, depending on your ability. 
• Build up gradually: You do not need to reach a tough exercise routine immediately. Increase the duration or intensity slowly as your fitness improves¹². 
• Get expert support if needed: Consider speaking with a physiotherapist or qualified exercise professional if you are new to exercise, have health concerns, or are unsure how to exercise safely. They can help you choose suitable activities and adjust your exercise plan to your abilities and needs¹³. 

Also Read: How to Stay Consistent With GLP-1 Medication: Tips, Challenges, Benefits & Long-Term Success

Conclusion

Starting a GLP-1 medicine can feel like a big change, but you do not have to figure everything out on your own. Mild digestive symptoms and changes in appetite can occur as your body adjusts, but regular follow-ups help your doctor manage your dose and monitor your health. If you have questions or notice something that concerns you, contact your doctor or healthcare team rather than relying on internet searches, changing your dose yourself or ignoring symptoms. 

Frequently Asked Questions (FAQs)

References 

1. GLP-1 agonists. MedlinePlus. 2026. Available from: https://medlineplus.gov/ency/article/007853.htm 

2. Ozempic. 2026. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/209637s038lbl.pdf 

3. Mounjaro. 2026. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/215866s009lbl.pdf 

4. Gorgojo-Martínez JJ, Mezquita-Raya P, Carretero-Gómez J, et al. Clinical recommendations to manage gastrointestinal adverse events in patients treated with GLP-1 receptor agonists: A multidisciplinary expert consensus. J Clin Med. 2022;12(1):145. doi:10.3390/jcm12010145  https://pubmed.ncbi.nlm.nih.gov/36614945/

5. Filippatos TD, Panagiotopoulou TV, Elisaf MS. Adverse effects of GLP-1 receptor agonists. Rev Diabet Stud. 2014;11(3):202-230. doi:10.1900/RDS.2014.11.202 https://pubmed.ncbi.nlm.nih.gov/26177483/

6. Wegovy. 2023. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/215256Orig1s006lbl.pdf 

7. GLP-1 receptor agonists: reminder of the potential side effects and to be aware of the potential for misuse. GOV.UK. 2024. Available from: https://www.gov.uk/drug-safety-update/glp-1-receptor-agonists-reminder-of-the-potential-side-effects-and-to-be-aware-of-the-potential-for-misuse? 

8. Dobbie LJ, Parretti HM, Fallows E, et al. Ten top tips for the management of GLP-1 receptor agonists in adults within primary care. Obes Facts. 2025;18(6):535-540. doi:10.1159/000546472  https://pubmed.ncbi.nlm.nih.gov/40388902/

9. GLP-1 medicines for weight loss and diabetes: what you need to know. GOV.UK. 2026. Available from: https://www.gov.uk/government/publications/glp-1-medicines-for-weight-loss-and-diabetes-what-you-need-to-know/glp-1-medicines-for-weight-loss-and-diabetes-what-you-need-to-know 

10. GLP-1 and dual GIP/GLP-1 receptor agonists: potential risk of pulmonary aspiration during general anaesthesia or deep sedation – GOV.UK. 2025. Available from: https://www.gov.uk/drug-safety-update/glp-1-and-dual-gip-slash-glp-1-receptor-agonists-potential-risk-of-pulmonary-aspiration-during-general-anaesthesia-or-deep-sedation 

11. Mozaffarian D, Agarwal M, Aggarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: A joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and the Obesity Society. Obes Pillars. 2025;15:100181. doi:10.1016/j.obpill.2025.100181 https://pubmed.ncbi.nlm.nih.gov/40445127/

12. Codella R, Senesi P, Luzi L. GLP-1 agonists and exercise: The future of lifestyle prioritization. Front Clin Diabetes Healthc. 6:1720794. doi:10.3389/fcdhc.2025.1720794  https://pubmed.ncbi.nlm.nih.gov/41367404/

13. Mulcahy J, DeLaRosby A, Norwood T. Transforming Care: Implications of Glucagon Like Peptide-1 Receptor Agonists on Physical Therapist Practice. Phys Ther. 2025 Jun 2;105(6):pzaf061. doi: 10.1093/ptj/pzaf061. PMID: 40305684; PMCID: PMC12203058. https://pubmed.ncbi.nlm.nih.gov/40305684/

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