Allurion Gastric Balloon Side Effects: What to Expect

The decision to start a weight loss programme is not made lightly. Before committing, most people want an honest answer to one question: what will this actually feel like?

The Allurion Gastric Balloon is well-tolerated compared to surgical alternatives, but it does produce side effects — particularly in the first one to two weeks. Understanding what is normal, what is manageable, and what requires medical attention helps you prepare realistically and respond appropriately if symptoms arise.

Why Side Effects Occur

When the Allurion Balloon is swallowed and inflated in your stomach, your body treats it as a foreign object and responds accordingly. The stomach is a muscular organ accustomed to receiving and processing food — a 550ml fluid-filled balloon occupying roughly one-third of its capacity is an unusual presence.

The initial side effects are largely the body’s adjustment response. The stomach undergoes a period of adaptation, during which it learns to accommodate the balloon alongside food and fluid. This process typically takes one to two weeks.

The absence of anaesthesia, endoscopy, and surgery means there is no surgical recovery involved. The side effects you experience are gastrointestinal, not post-operative.

Common Side Effects in the First Week

Nausea

Nausea is the most frequently reported side effect in the first three to five days. It tends to be most pronounced immediately after placement and gradually eases as the stomach adjusts. Anti-nausea medication is routinely prescribed as part of your programme protocol.

Eating small amounts of soft or liquid food, remaining upright after eating, and avoiding strong smells can all help manage nausea in the early days.

Abdominal Cramping and Discomfort

Cramping and a sensation of pressure or fullness are common in the first week. This is the stomach responding to the physical presence of the balloon. Antispasmodic medication prescribed by your medical team helps reduce cramping significantly.

The discomfort is typically described as similar to a stomach upset rather than sharp or severe pain. It does not prevent most patients from going about their normal daily activities.

Vomiting

Vomiting can occur, particularly if solid foods are introduced too quickly. The dietary protocol for the first week — liquids, then soft foods, then gradual reintroduction of solid meals — is specifically designed to minimise this risk.

Following the dietary guidance closely in the first ten days is one of the most effective ways to reduce the intensity and duration of side effects.

Reduced Appetite and Early Satiety

Feeling full after very small amounts of food is expected and intentional — it is how the balloon achieves its effect. In the first week, this can feel uncomfortable rather than helpful. Within two to three weeks, most patients describe it as easier to manage and find it supports their dietary changes naturally.

Belching and Bloating

Increased belching and a sensation of bloating are common in the early weeks. These are caused by the displacement of gastric gas and the physical presence of the balloon. Both typically resolve as the stomach adapts.

Side Effects That May Persist into the Programme

For a smaller proportion of patients, some symptoms persist beyond the initial two weeks. These are less common but worth understanding.

Acid Reflux and Heartburn

Some patients experience acid reflux or heartburn during the programme, particularly in the first month. Avoiding lying down immediately after eating, reducing portion sizes, and taking prescribed antacid medication manages this effectively in most cases.

Patients with a history of severe gastro-oesophageal reflux disease (GERD) are assessed carefully before placement, as this may affect eligibility.

Constipation

Reduced food intake and altered eating patterns can slow digestion in some patients. Maintaining adequate fluid intake, eating sufficient fibre-rich soft foods, and light physical activity support normal bowel function. Your medical team will advise on appropriate management if constipation becomes persistent.

Fatigue

Some patients experience low energy in the first two to four weeks, largely as a result of reduced caloric intake. This typically eases as the body adjusts to the new eating pattern and nutritional needs are met through the programme’s dietary guidance.

Rare but Serious Side Effects

Serious complications from the Allurion Balloon are uncommon. Published clinical data across more than 100,000 patients globally reports a serious adverse event rate of below 0.3%.

Rare complications can include balloon deflation before the expected 16-week period, gastric obstruction, or in very rare cases, spontaneous balloon passage without deflation. These events are managed promptly when identified.

Contact your medical team immediately if you experience:

• Severe or worsening abdominal pain that does not respond to prescribed medication
• Persistent vomiting beyond the first week, or inability to keep fluids down
• Signs of dehydration — dark urine, dizziness, dry mouth
• Fever above 38°C
• Sudden relief from balloon-related symptoms, which may indicate early deflation

How Ottawa Health Center Supports You Through Side Effects

The Allurion programme at Ottawa Health Center includes a full six-month support structure. You are not managing side effects alone.

At the start of your programme, you receive a medication protocol for the first one to two weeks, dietary guidelines for each phase, and direct access to our medical team. Check-ins are scheduled throughout the programme to monitor your progress and adjust your management plan if needed.

Most patients find that once the first two weeks pass, side effects are no longer a meaningful concern. The balloon becomes part of daily life, appetite is naturally reduced, and the focus shifts to building the dietary and lifestyle habits that sustain results after the programme ends.

A Realistic Expectation

The first week is the hardest. Most patients describe it honestly as uncomfortable — and equally describe being glad they persisted once that adjustment period passed.

The Allurion Balloon produces meaningful, clinically proven weight loss without surgery or anaesthesia. The side effect profile, while real, is considerably milder than that of surgical bariatric procedures and resolves on a far shorter timeline.

If you are weighing the Allurion Balloon as an option and want to understand whether it is appropriate for your health profile, a free consultation with our medical team is the right starting point.