Weight Loss Injection Side Effects: Common Reactions, Risks & How to Manage Them Safely

Article Summary:

• Side effects of weight loss injections are common but often improve over time. These can include nausea, diarrhea, constipation, indigestion and vomiting.
• Less common but more serious side effects can include pancreatitis and gallbladder disease. Following your prescribed diet, treatment plan and dosing schedule can help manage side effects.
• It’s important to monitor how you feel and contact your clinical team if side effects persist or worsen.

Weight Loss Injection Side Effects: Common Reactions, Risks & How to Manage Them Safely

Most treatments can cause side effects, and weight loss injections are no different. If you’re just starting treatment, it’s important to know which symptoms you may experience and how you can manage them.

Here, we break down common and serious side effects. We’ll also offer tips to relieve discomfort and help make your treatment as straightforward as possible.

Who can use weight loss injections?

Weight loss injections may support weight loss and weight management if you’re living with obesity. They may also be suitable for you if you’re overweight and have obesity-related health conditions. ^[1] These include type 2 diabetes and hypertension (high blood pressure). However, it's important to highlight that any weight loss treatment should be accompanied by positive lifestyle changes (like following a well-balanced, reduced-calorie diet and increased physical activity), and always in consultation with a trusted, licensed healthcare provider. ^[2]

Who shouldn’t use weight loss injections?

Weight loss injections aren't suitable for you if you’re currently pregnant or breastfeeding. For further information, including important advice on using contraception while on weight loss medication, please refer to your patient information leaflet.

Do not use weight loss injections if you have a personal or family history of medullary thyroid carcinoma (MTC), a type of thyroid cancer, or if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

You also shouldn’t take weight loss injections if you're allergic to any of the ingredients in the medication. Severe allergic reactions are rare, but you should seek immediate medical attention if you notice a skin rash, throat swelling or difficulty breathing.

Be sure to share your full medical history (both physical and mental) with your healthcare provider when discussing weight loss treatment options. This will enable them to prescribe the best treatment for you based on your personal circumstances. Make sure to include details on any pre-existing conditions like kidney issues, a history of pancreatitis, gallstones or severe digestive problems. Finally, always make your healthcare provider aware if you have previously had bariatric surgery (weight loss surgery.)

Common weight loss injection side effects

There are several common and extremely common side effects of weight loss injections to be aware of. These may include:

• Nausea and vomiting
• Diarrhea
• Constipation
• Indigestion
• Injection site reactions
• Increased heart rate
• Dizziness

All of these side effects are generally mild to moderate. They’re also often manageable with over-the-counter remedies and simple lifestyle adjustments (we’ll talk more about those later).

It's important that you monitor any side effects and consult your healthcare provider if they either persist or worsen. You can learn more about side effects in your patient information leaflet.

Serious side effects and when to seek medical attention

Most people who take weight loss injections will only experience mild side effects. However, serious adverse side effects may occur.

If you experience any of the following, stop taking your treatment and seek immediate medical attention:

• Pancreatitis (inflammation of the pancreas) or acute pancreatitis: prolonged severe stomach (abdominal pain) which may move to your back, with or without vomiting.
• Dehydration / Acute kidney failure: dark yellow/strong-smelling urine, feeling extremely thirsty, dizziness, lightheaded, puffy hands, face, or feet.
• Gallbladder problems or acute gallbladder disease: severe abdominal pain, yellowing of skin or eyes or high fever with chills.
• Serious allergic reaction: difficulty breathing, swelling of face and throat, fast heartbeat, rash, abdominal cramps, nausea and vomiting.
• Severe hypoglycemia (severe low blood sugar): disorientation, loss of consciousness or seizures.
• Depression, suicidal thoughts or behavior: new or worsening mood changes, feeling sad or hopeless, thoughts of hurting yourself. ^[3][4][5]

For more information about side effects, refer to your patient information leaflet.

Managing side effects

Side effects often improve as your body adjusts to treatment. However, there are still some things that you can do to help manage any side effects that you do experience.

Diet and healthy habits

To reduce nausea and vomiting, eat small portions, limit fatty and spicy foods and avoid eating anything that has a strong smell. Eating crackers, mint-based foods or ginger supplements or drinks may also lessen these side effects.

If you’re experiencing side effects like constipation and indigestion, a fibre-rich diet, staying hydrated and doing regular exercise should help you to manage your symptoms. And if you’re experiencing diarrhea, try sticking to bland food for a few days as this could help settle your stomach.

Resting can also help to reduce fatigue. Experts recommend 7-9 hours of sleep a night to support hormonal balance. ^[6] This could help prevent you from reaching for fast-acting energy snacks, which are usually low in nutritional benefit and high in sugar and fat. ^[7]

Medication

Over-the-counter medication may help you to manage mild, common side effects like constipation, diarrhea and even some injection site reactions. Be sure to speak to your healthcare provider before taking any additional treatment.

Remember, most side effects tend to resolve as your body adjusts to the treatment. If they’re severe or persistent, contact your healthcare provider.

Find out what treatment is suitable for you on our website.