Compare · Medicines and surgery
Mounjaro, Wegovy or a gastric sleeve?
What the weight-loss injections are, how they compare with surgery, and what the Irish regulators say. This is general information: talk to your GP.
Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only injections that reduce appetite. In trials, people lost about 15% of their weight on semaglutide and up to about 20% on the highest dose of tirzepatide, over about 16 months. Surgery leads to more: the HSE says 20% to 40%. Much of the weight tends to come back when the injections stop. Only Saxenda is reimbursed for weight loss by the HSE, and the HPRA warns never to buy these medicines online.
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What the medicines are
| Medicine | What it is | HSE reimbursement for weight loss |
|---|---|---|
| Mounjaro | Tirzepatide, an injection | Not reimbursed for weight loss |
| Wegovy | Semaglutide, an injection | Not reimbursed for weight loss |
| Ozempic | Semaglutide, licensed for type 2 diabetes | Funded for type 2 diabetes only |
| Saxenda | Liraglutide, an injection | The only one reimbursed for weight loss |
All are prescription-only medicines. Your GP or a specialist decides whether one is right for you. Reimbursement decisions change, so ask your pharmacist what applies now.
Injections and surgery compared
| Weight-loss injections | Gastric sleeve | |
|---|---|---|
| Typical weight loss | About 15% (semaglutide) to about 20% (tirzepatide, top dose) in trials | 20% to 40% with surgery, says the HSE; up to 25 to 30% for a sleeve |
| How long it lasts | Weight tends to return after stopping | Permanent change; some regain is common |
| Commitment | Ongoing injections, for as long as they're needed | One operation, then vitamins and follow-up for life |
| Main side effects | Nausea, sickness and other stomach upsets, usually early | Surgical risks; reflux, vitamin loss |
| Reversible | Yes, stop the medicine | No |
Trial results: semaglutide, about 15% average weight loss at 68 weeks; tirzepatide, about 15% to 21% by dose at 72 weeks. In the semaglutide trial's follow-up, people regained about two-thirds of the weight they'd lost within a year of stopping.
What the HPRA says
The HPRA, Ireland's medicines regulator, warns the public not to buy weight-loss medicines online. Products sold online or through social media can be falsified, counterfeit or contaminated, and contain harmful substances or the wrong dose. Its advice: only use these medicines under the supervision of a prescriber you trust, from a registered pharmacy, with a valid prescription. It also says these medicines aren't authorised for short-term use. More at hpra.ie.
Who each suits
There's no simple rule, and it's a decision for you and your doctors. In general terms, medicines are often tried first, especially at a lower BMI, by people who don't want or can't have surgery, or while waiting for surgery. Surgery tends to be considered at a higher BMI, where larger and more lasting weight loss matters most for health. Some people use both at different times; your surgeon and GP will advise.
Questions people ask
Is Mounjaro better than a gastric sleeve?
They work differently. In trials, the top dose of tirzepatide led to about 20% weight loss, while the HSE says surgery leads to 20% to 40%. Weight tends to return after stopping the injections. Talk to your GP about what suits your health.
Can I get Wegovy or Mounjaro on the medical card?
Not for weight loss at present. Saxenda is the only GLP-1 medicine the HSE reimburses for weight loss. Ozempic is funded for type 2 diabetes. Ask your pharmacist what applies now.
Is it safe to buy weight-loss injections online?
No. The HPRA warns that products sold online can be fake, contaminated or the wrong dose. Only use them on prescription, from a registered pharmacy.
Can I take weight-loss injections after a gastric sleeve?
Sometimes doctors use them after surgery, for example for weight regain. It's a decision for your surgeon and GP.
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