Starting out on Saxenda? You might be wondering what to expect. In terms of results, Saxenda weight loss injections work pretty well: after a year, you might lose around 7% of your starting weight.
But what about side effects? Yep—like all medicines, Saxenda can come with those, too. Though most of the time, they aren’t anything to worry about and will go away on their own.
Still, it’s important to know which symptoms to look out for—and how you can deal with them. We’ve answered all your questions below.
What are the most common side effects of Saxenda?
First, let’s take a look at the most common Saxenda side effects. These might affect more than one in ten people:
- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Headache
You might have noticed that almost all of those are linked to the gut. That’s because of how Saxenda works: one of the ways it makes you feel full is by slowing down your digestion. This can bring on symptoms like the above.
Other gut-related Saxenda side effects include burping, bloating, passing wind, indigestion, and stomach pain or discomfort. Up to one in ten people might experience these.
What are serious side effects of Saxenda?
At Voy, we’re sometimes asked: what are the worst side effects of Saxenda? It’s a tricky question. We can’t say which symptoms you’ll get nor how intense you’ll find them, because everyone’s different. Some people don’t get any side effects at all.
It’s rare, but Saxenda can have more serious or long-term side effects. If you do notice any of the signs or symptoms described here, get in touch with your doctor right away.
Severe nausea and vomiting, leading to dehydration
If you’re being sick or having diarrhoea, make sure you’re drinking plenty of water to replace the fluids you’re losing. That’s because in severe cases, dehydration may lead to kidney failure—even if you’ve never had issues with your kidneys before. It’s also a good idea to take electrolyte tablets or oral hydration sachets to replenish your electrolytes.
So, if your symptoms aren’t going away, contact your provider asap.
Pancreatitis
Remember earlier, when we mentioned that Saxenda works by making you feel full? Aside from acting on the gut, it also does this by stimulating the pancreas. And according to clinical trials, this can lead to pancreatitis (inflamed pancreas) in less than 1% of people.
Severe pain in the upper part of your abdomen (either in the centre or on the left side), feeling or being sick, and having a high temperature are all signs of pancreatitis.
Gallbladder problems
Per clinical research, around 2% of people on Saxenda reported gallstones while less than 1% had an inflamed gallbladder.
These don’t always cause symptoms, but the main sign to look out for is sudden, sharp pain in the right upper part of your abdomen that doesn’t go away. You might also have a fever, feel confused or sweaty, or your skin or eyes might become more yellow (this is called jaundice).
Can Saxenda cause cancer?
This is another question we get every so often: is cancer ever a side effect of Saxenda? And the answer is that we don’t have enough scientific evidence to say.
In studies with rats and mice, some animals treated with Saxenda did develop thyroid cancer. We know that sounds scary, but it doesn’t mean that the same thing will happen in people. Some human studies found that people with type 2 diabetes who were taking medicines like Saxenda didn’t get cancer, for example.
All in all, this is not strong enough evidence for us to say that Saxenda causes cancer—nor to guarantee that it won’t. We just don’t know enough to say for sure.
So, if you or anyone in your family has ever had medullary thyroid carcinoma or multiple endocrine neoplasia type 2, Saxenda isn’t recommended.
Do Saxenda side effects go away?
Most of the time, yes.
Okay, but how long do Saxenda side effects last? Typically, symptoms will go away after a few days or weeks. If they don’t, or are getting worse, see your doctor.
To reduce your risk of side effects, you first start on the lowest dose of Saxenda and then gradually increase it each week. This is so your body can get used to the medicine and handle higher strengths later on.
Symptoms tend to come on when you first start on Saxenda or as you increase your dose. But they’ll usually clear as your body builds up a tolerance to the medicine.
Are there side effects of stopping Saxenda? The medicine will gradually stop working as it gets flushed out of your system. That means that any side effects you were having should clear up, while you also might notice other changes like your appetite coming back.
How to manage the side effects of Saxenda
Happily, there are ways to make your side effects easier to deal with.
Eat smaller meals
Opting for smaller meals lessens the pressure on your stomach and may help it empty faster—as well as reducing the buildup of gas that forms when food is being digested. This could help ease your gut symptoms.
Avoid certain foods
It can help to steer clear of certain foods that can upset your gut and make your symptoms worse, like those high in fat or spicy or acidic.
What about fibre? While it’s generally considered good for digestion and may help with constipation, it’s not advised for people with diarrhoea. Ask your provider if you’re not sure.
Stay hydrated
Saxenda can decrease your thirst signal, so you may feel less thirsty. Make sure you keep an eye on your water intake and stay hydrated. If you’re having symptoms where you’re losing fluids, like diarrhoea and being sick, it’s even more important.
Side effects support at Voy
"If you're using Voy and you experience any side effects, rest assured that our expert clinicians are just a message or phone call away. They can adjust your dose, prescribe medication to ease your symptoms, or simply offer reassurance.
Everyone responds differently to weight loss treatment and we'll help you find what feels right for you."

Who should not use Saxenda?
You shouldn’t take Saxenda if you’re pregnant or breastfeeding, if you or anyone in your family has ever had the cancers we mentioned above, or if you’ve ever had a serious allergic reaction to any of the ingredients in Saxenda.
If you’ve had problems with your pancreas or gallbladder, you can't use Saxenda.
If you have kidney problems, speak to your provider before using the medication
Is Saxenda right for you?
Every medicine comes with the risk of side effects. When deciding whether to try Saxenda, you should weigh these up against its potential benefits.
We can help with that. Through our weight loss programme, our clinicians will advise on which weight loss medication is best for you, and explain how Saxenda compares to Wegovy or Mounjaro. You’ll also get personalised support and guidance from our team of coaches, who will help you make lifestyle changes that last.
Ready to take your next step? Fill out this short quiz to see if you’re eligible for the programme.