Saxenda side effects: what to expect and what to do about them

Side effects per build-up week: what to expect when

The side effects follow the dosing schedule. Each week you increase by 0.6 mg, and each increase can temporarily bring the nausea back. This is how it goes for most users:

1. Week 1 (0.6 mg): mild nausea and a full feeling, especially after eating. Many users still notice little.
2. Week 2 (1.2 mg): the nausea increases, sometimes with belching or a bloated feeling. Diarrhoea or, on the contrary, constipation may start.
3. Week 3 (1.8 mg): the peak of the gastrointestinal symptoms for many users. Reduced appetite becomes clearly noticeable.
4. Week 4 (2.4 mg): symptoms usually level off. Tiredness may stand out, often because you are eating less.
5. From week 5 (3.0 mg): the maintenance dose. For most users, the symptoms have largely disappeared after 2 to 4 weeks on this dose.

If you have a lot of symptoms in a particular week, you can stay on the same dose for an extra week in consultation with the doctor. That is not a failure: the leaflet provides for it. The full dosing schedule and how to use the pen are in our article on Saxenda dosage.

Nausea, heartburn, diarrhoea and constipation: what can you do yourself?

The gastrointestinal symptoms of Saxenda are linked to how it works: the medicine slows gastric emptying. Food stays in your stomach longer, and you feel that. Smaller portions, eating slowly and limiting fatty or fried food take the sharpest edge off. Read more about Saxenda vs Mysimba.

For nausea, it helps not to inject on an empty stomach and to avoid heavy meals in the evening. Drink water in small sips throughout the day. With heartburn or belching, do not eat just before bed and give fizzy drinks and spicy food a miss for a while.

Diarrhoea and constipation can both occur, sometimes alternately. With diarrhoea, make sure you get enough fluid and salt. With constipation, help your bowels with fibre, extra water and daily exercise. If that does not work after a week, the doctor can advise a mild laxative.

If you lose a lot of weight in a short time or keep little down, report it. Dehydration is the biggest risk with persistent vomiting or diarrhoea, including for your kidneys.

Tiredness, palpitations and mood on Saxenda

Saxenda can make you tired. Tiredness is listed in the leaflet as a common side effect and is usually linked to eating less and drinking less. If you eat too little protein and carbohydrate, you lack energy. Eating regularly, even without hunger, and drinking enough help. If the tiredness lasts for weeks, have the doctor take a look.

Palpitations do occur. Liraglutide raises the resting heart rate by a few beats per minute on average; this is stated in the product information. Most users do not notice it. If you often feel your heart pounding at rest, or feel dizzy with it, discuss it with the doctor. They can check your heart rate and adjust the dose if in doubt.

A lot has been said about mood and depression. The European Medicines Agency (EMA) investigated reports of low mood and suicidal thoughts with GLP-1 medicines and concluded in April 2024 that the available evidence does not support a causal link. If you feel low or not yourself during use, report it anyway. Losing weight, eating less and sleeping worse can affect your mood, and the doctor can take that into account.

Want to lose weight with medication, but worried about the side effects? With medical weight loss with injections, your own doctor builds up the dose at your pace and can be reached if you have symptoms →

Serious side effects: when do you call the doctor?

Call immediately if you have severe, persistent abdominal pain radiating to your back, possibly with vomiting. That may be inflammation of the pancreas (pancreatitis): rare, but serious. Stop injecting until you have spoken to the doctor.

These signs are also a reason to get in touch the same day:

• Pain in the upper right abdomen, especially after eating, sometimes with fever or yellow skin: possibly gallstones or an inflamed gallbladder. Rapid weight loss increases that risk.
• Persistent vomiting or diarrhoea with passing little urine, a dry mouth or dizziness: dehydration, with a risk to the kidneys.
• Swelling of the face, lips or throat, shortness of breath or a rash: an allergic reaction. If you are short of breath, call 112 (the emergency number).
• Trembling, sweating, palpitations and hunger if you also use diabetes medication: low blood sugar.
• A lump or swelling in the neck, hoarseness or difficulty swallowing: have your thyroid checked.

Saxenda must not be used during pregnancy, when trying to conceive or while breastfeeding. How that works is covered in our article on weight loss medication and pregnancy. With a previous inflammation of the pancreas, severe kidney or liver problems, an eating disorder or medullary thyroid cancer in the family, the doctor also assesses whether the medicine is suitable. With a medical weight loss with injections programme, you have direct contact with your own doctor if you notice signs like these.

Long-term side effects

More is known about Saxenda in the long term than about the newer medicines, because liraglutide has been licensed for weight management since 2015. In the SCALE study (New England Journal of Medicine, 2015), 3,731 participants used liraglutide 3.0 mg or a placebo for 56 weeks. The liraglutide group lost an average of 8.4 kg, the placebo group 2.8 kg. Serious adverse events occurred in 6.2 percent of liraglutide users and 5.0 percent of the placebo group. Results vary from person to person.

The three-year follow-up of the same study (Lancet, 2017) showed that the gastrointestinal symptoms decrease over time and that no new types of side effects emerged in three years. However, about half of the participants dropped out early, in both groups. Side effects to keep an eye on in the longer term are gallstones (with rapid weight loss) and the resting heart rate.

If you stop Saxenda, your appetite returns and many people regain weight. That is not a side effect, but a consequence of the effect wearing off. That is why a programme includes a plan for the phase after the medication. What users report about longer use is covered in Saxenda reviews.

Is Saxenda dangerous and is it insulin?

Saxenda is not insulin. It contains liraglutide, a GLP-1 receptor agonist that mimics the gut hormone GLP-1. It curbs the appetite and slows gastric emptying. It only lowers blood sugar when it is too high, which is why low blood sugar is rare without diabetes medication. The same substance is also found in other brands; see our article on liraglutide. Read more about how to buy Saxenda.

Saxenda is not dangerous if you use it as prescribed, under a doctor's supervision. Bijwerkingencentrum Lareb (the Netherlands Pharmacovigilance Centre) received more than 1,000 reports about liraglutide and semaglutide in 2023, more than 100 of which concerned serious side effects such as inflammation of the gallbladder and heart rhythm disorders. The reports are in line with the known side effects. Lareb and the CBG (the Dutch Medicines Evaluation Board) mainly warn against use without medical supervision, for example via illegal web shops.

So the risks lie in incorrect use: building up too quickly, injecting without checks on the kidneys, pancreas and thyroid, or counterfeit pens. How the risks of the whole group of medicines compare is covered in our overview of GLP-1 side effects.

Saxenda and alcohol

Alcohol is not a forbidden combination with Saxenda, but it intensifies the gastrointestinal symptoms and, with diabetes medication, increases the risk of low blood sugar. Many users notice that they feel less like drinking alcohol and are affected by it sooner. During the build-up phase, it is better to leave alcohol alone. More on this in our article on Saxenda and alcohol. Read more about how fast Saxenda works.

Want to know whether medical weight loss is right for you? Take the eligibility check and the doctor will assess your situation →

Frequently asked questions about Saxenda side effects

What are the most common side effects of Saxenda?

Nausea, vomiting, diarrhoea, constipation and reduced appetite. They occur in more than 10 in 100 users, especially during the build-up phase, and usually decrease afterwards. Tiredness, headache and irritation at the injection site are also common.

Can Saxenda make you tired?

Yes, tiredness is listed in the leaflet as a common side effect. It is usually because you are eating and drinking less. Eating regularly, enough protein and water help. If it lasts for weeks, discuss it with the doctor.

What does Saxenda do in the long term?

In the SCALE study, liraglutide 3.0 mg was followed for up to three years. The gastrointestinal symptoms decreased over time and no new types of side effects appeared. Points to watch in the long term are gallstones with rapid weight loss and a slightly higher resting heart rate.

What are the serious side effects of Saxenda?

Inflammation of the pancreas, gallstones or inflammation of the gallbladder, dehydration with kidney problems, allergic reactions and low blood sugar in combination with diabetes medication. They are rare. Call immediately if you have severe abdominal pain radiating to the back or swelling of the face or throat.

Can Saxenda cause depression?

The European Medicines Agency concluded in April 2024 that the available evidence does not support a causal link between GLP-1 medicines such as liraglutide and suicidal thoughts or self-harm. If you feel low during use, tell your doctor.

How long can you use Saxenda?

There is no fixed maximum duration of use. The doctor evaluates the effect and the side effects; according to the product information, you stop if you have lost less than 5 percent of your starting weight after 12 weeks on the maintenance dose. How long you continue is something you decide together with the doctor.

What happens when you stop Saxenda?

Your appetite returns and your weight may increase again if your eating pattern has not changed. So stop in consultation with the doctor and with a plan for afterwards. How to approach that is covered in our article on stopping Saxenda.

Why have I stopped losing weight on Saxenda?

After a few months, weight loss levels off for many users: the body finds a new balance. A dose that is too low, missed injections or a changed eating pattern can also play a part. What you can do then is covered in Saxenda not working.

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