Weight-loss medication: what to know

Everyone is talking about GLP-1 medicines and clear information is hard to find. Here's what they are, how they work, what to expect from them, and why the plate still matters while you're on them.

Information checked on 2026-09-28. General information, not medical advice. How we calculate

This is general information, not medical advice. These medicines are prescription-only. Whether they suit you, which one and at what dose is decided by a doctor who knows your health and your other medicines. Dumpli does not prescribe or sell medicines.

What they are

“Weight-loss injections” usually means GLP-1 medicines. The active substances are semaglutide, liraglutide and tirzepatide; brand names differ by indication and country. They act like a hormone your gut releases after a meal: they slow stomach emptying, increase fullness and reduce hunger. You eat less not through willpower, but because you want less.

One detail that often gets mixed up: Ozempic is licensed for type 2 diabetes, while weight management uses separate products – the same or a similar substance, with their own indication and dosing schedule.

Who they're prescribed for

The decision is a doctor's, and it isn't based on one number: body mass index and waist, other conditions (type 2 diabetes, high blood pressure, sleep apnoea, fatty liver), what has already been tried, other medicines and contraindications all count. More about BMI itself and its limits is in its own guide.

These are not medicines for losing a few cosmetic kilos, and where there is a history of an eating disorder the question is looked at especially carefully.

What to expect, and what not to

  • Hunger drops, habits stay. The medicine doesn't tell you what to eat. Eating little but mostly sweet things still leaves you short of protein and micronutrients.
  • Pace still has limits. Very fast weight loss also means more muscle lost – see why fast weight loss doesn't work.
  • Appetite returns when treatment stops. In trials, part of the weight comes back afterwards. That's why this is framed as long-term treatment, not a “course”.
  • A medicine is not a check-up. Blood pressure, blood sugar, cholesterol and thyroid are still worth testing.

Side effects and safety

The common ones are digestive: nausea, vomiting, diarrhoea and constipation, especially when starting or increasing the dose. Rarer but more serious are pancreatitis and gallbladder problems. Some conditions rule these medicines out, so your doctor needs your full history, including your family's.

Don't buy these medicines from unclear sources. “Weight-loss pens” sold online without a prescription are often counterfeit or badly stored. The only safe route is a prescription and a pharmacy.

Why food still matters on them

When appetite drops, it's easy to end up short of protein and fibre – and that shortage is what drives muscle loss, tiredness and digestive trouble. In practice, doctors and dietitians usually suggest:

  1. A protein source at every meal, even when portions are small. How much you need is in the protein guide; ideas are in high-protein recipes.
  2. Smaller but regular meals – nausea is usually eased by smaller portions more often, not by skipping food.
  3. Fibre and fluids – constipation is one of the most common complaints.
  4. Resistance work twice a week – so what you lose is fat, not strength.

A Dumpli plan is useful here not as a “diet” but as a way to get enough protein and vegetables into a smaller amount of food. The safety limits we never cross are on our methodology page.

When to talk to a doctor

Before you change how you eat to lose weight, talk to your doctor first if:

  • you are pregnant or breastfeeding;
  • you have diabetes or take medicines that affect your blood sugar;
  • you have kidney disease, heart disease or another long-term condition;
  • you are under 18;
  • you have or have had an eating disorder;
  • you are losing weight without trying.
  • you are considering, or already taking, weight-loss medication – then plan any change in how you eat with the doctor treating you;

If your relationship with food worries you, you can talk to a doctor or a psychologist. If you're struggling right now, call your local emergency number or find a free helpline at findahelpline.com.

Honestly: this guide was not written or reviewed by a doctor – it is general public information. Spotted something inaccurate? Tell us and we'll correct it and date the change.

Frequently asked questions

What are GLP-1 medicines?

Prescription medicines (semaglutide, liraglutide, tirzepatide) that act like GLP-1, a hormone your gut releases after eating: they slow stomach emptying and reduce hunger. Some are licensed for type 2 diabetes, others for weight management.

Is Ozempic for weight loss?

Ozempic is licensed to treat type 2 diabetes. Weight management uses separate products – the same or a similar active substance, but their own indication and dosing. Which one, if any, is a doctor's decision.

Who are they prescribed for?

A doctor looks at the whole picture: body mass index, other conditions (type 2 diabetes, high blood pressure, sleep apnoea), what has been tried before, and any contraindications. They are not medicines for losing a few kilos before summer.

What are the common side effects?

Most often nausea, vomiting, diarrhoea or constipation, especially when the dose goes up. Rarer but more serious: pancreatitis and gallbladder problems. Any new symptom should be reported to your doctor.

Does the weight come back if you stop?

In trials, stopping the medicine usually means part of the lost weight returns as appetite recovers. That's why doctors talk about long-term treatment, and about the eating and movement habits that remain either way.

Does Dumpli prescribe or sell these medicines?

No. Dumpli is a meal-planning app: we are not a medical provider, and we neither prescribe nor sell medicines. If a doctor has prescribed treatment, our plan can help you eat enough protein and enough food – but the treatment itself is between you and your doctor.

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