If you're looking into medical treatments to help you alongside your weight loss journey, you've probably noticed there are more options available than ever before, for both injections and pills.
But there isn't one single ‘best’ weight loss medication. Ultimately, the right choice depends on your health, your budget, and what matters most to you, whether that's cost, effectiveness, or convenience.
Read on to discover which treatment is right for you.
Three key takeaways
The right treatment for you depends on things like your medical history and whether you'd prefer a weekly injection or a daily tablet.
Mounjaro currently produces the greatest average weight loss in clinical trials, while weight loss pills like Foundayo are more convenient, as they’re a daily tablet with no food or drink restrictions.
Wegovy is the only weight loss injectionlicensed in the UK to reduce the risk of heart issues in patients who are overweight or obese.
Best weight loss medication at a glance
Everybody responds differently to weight loss medication, so what worked well for your friend might not work the same for you. Here's a quick overview of how they compare.
What's the most effective weight loss medication in clinical trials?
Out of all the weight loss treatments available, Mounjaro has the largest average weight loss shown in clinical trials. In SURMOUNT-1, people on the highest dose of Mounjaro (15mg) lost an average of 22.5% of their body weight over 72 weeks.
To put that into perspective, if you weighed 100kg (around 16 stone), you could lose about 22.5kg, or 3.5 stone, in just under a year and a half.
Of course, that doesn’t mean other weight loss treatments aren’t effective. The Wegovy injection follows close behind, with an average of 21% weight loss over 72 weeks at the highest dose.
“It’s important to remember that everyone responds differently, and it isn’t always about what looks better on paper. It’s about how the treatment works for you personally.”
The Wegovy pill is currently the most effective weight loss tablet available. In the OASIS 4 clinical trial, people taking the Wegovy pill lost an average of around 17% of their starting body weight after 64 weeks.
Interestingly, in a later analysis of the same trial, those who responded well to treatment (and lost at least 10% of their starting weight by week 16) went on to lose an average of 22% of their body weight by week 64.
But it’s still important to remember that results vary from person-to-person, and not everybody will lose weight at the same rate.
Which weight loss treatment reduces appetite the most?
Mounjaro targets both GIP and GLP-1 receptors, which are involved in appetite and blood sugar regulation.
“Mounjaro's dual-action formula is often linked to stronger results than single-receptor treatments like Wegovy. That said, everyone's appetite responds a little differently, so always speak to your clinician about what to expect.”
Ian Budd, Prescribing Pharmacist at Chemist4U
Which weight loss treatments work the fastest?
People who move up from Mounjaro 2.5mg to 5mg and then 7.5mg during the first 12 weeks may lose more weight over that period. However, all weight loss treatments start working on appetite and cravings at around the same time.
How much weight someone loses depends not only on their dose and how quickly they progress through the titration schedule, but also on the lifestyle changes they make alongside treatment.
For example, someone taking Foundayo for six months while consistently making healthy diet and exercise changes may lose more weight than someone taking Mounjaro for the same length of time without making any lifestyle adjustments.
The Wegovy injection and the Wegovy pill are the cheapest GLP-1 treatments, with both starting from £99 for your first dose. Meanwhile, Mounjaro starts from £148, and Foundayo starts from £109.
Pills also tend to work out cheaper once you're on amaintenance dose. The maximum dose of both Foundayo and the Wegovy pill costs £199 a month. That’s the same as the Wegovy 2.4mg injection, and cheaper than £298 a month for Mounjaro's maximum 15mg dose.
That makes tablets a sensible option if you're watching your treatment budget long-term.
Which weight loss medication has the fewest side effects?
“All GLP-1 medicines have very similar side effects, so symptoms like nausea, vomiting, diarrhoea, and constipation are common with Mounjaro, Wegovy injections and pills, and Foundayo alike, as they all work in a similar way.
“The one difference is that tablets don't come with any risk of injection site reactions (redness, itching, or bruising where you inject), simply because there's no injection involved.”
What's the best weight loss treatment for heart health?
The Wegovy injection is currently the only weight loss medicine licensed in the UK to help lower the risk of serious cardiovascular events, like heart attack and stroke, in adults who already have cardiovascular disease alongside obesity and overweight.
“Mounjaro and the Wegovy pill aren't licensed for this specific use yet, though all GLP-1 medicines can support heart health indirectly just by helping you lose weight.”
What's the most convenient weight loss medication?
Foundayo is the most convenient GLP-1 weight loss medication at the moment. Unlike other weight loss tablets, it's a small molecule rather than a peptide, which means it can survive digestion without you needing to fast.
You simply take one tablet a day, with or without food or water, whenever suits you.
It's also stored at room temperature rather than in the fridge. This means tablets like Foundayo and the Wegovy pill can be sent straight through your letterbox, meaning there's no need to stay in and wait for a delivery. This can make them better suited to busy lifestyles.
Whether a weekly injection or a daily tablet suits you better really comes down to personal preference, and if convenience matters more to you than what’s most effective.
Which weight loss treatment is best if you travel?
If you travel a lot, pills might be a better bet than injections. This is especially true of Foundayo, as you can take it any time, with or without food or water.
The Wegovy pill needs to be taken first thing in the morning on an empty stomach, with no more than 120ml of plain water, then a 30-minute wait before eating, drinking, or taking anything else.
That can be a hassle to fit around early flights or changing time zones, so Foundayo's flexible timing tends to suit frequent travellers better.
Whichever treatment you're on, though, it's worth keeping pens or pills in your hand luggage rather than the hold, since temperatures there can fluctuate.
What weight loss medication is best if you take contraception?
The Wegovy injection and pill are best if you take the contraceptive pill, as there's no evidence either affects how well oral contraception works. If you're taking the Wegovy pill, just leave a 30-minute gap after your tablet before taking your contraception.
“Both Mounjaro and Foundayo can reduce how well the contraceptive pill works.
“If you're taking either alongside the pill, you'll need to also use a barrier method, like condoms, or switch to a non-oral method of contraception, for 30 days after starting treatment and for 30 days after every dose increase.”
How to start your weight loss journey with Chemist4U
Getting started on your weight loss journey with Chemist4U couldn't be simpler. Just complete a quick online consultation, and our expert clinicians will review it to make sure your chosen treatment is safe and suitable for you.
If approved, we'll dispatch your treatment in discreet, temperature-controlled packaging (if needed), with fast and flexible delivery options available. Our clinicians are also on hand throughout your journey if you have any questions along the way.
You'll typically leave at least seven days between your last dose and your first dose of the new treatment. You won't always need to start at the lowest dose, either, as your prescriber will decide based on the dose you were previously on and how well you tolerated it.
Is retatrutide an effective weight loss medication?
Retatrutide has shown promising results in clinical trials, but it isn't licensed for use in the UK or US yet.
In terms of effectiveness, in the phase 3 TRIUMPH-1 trial, some participants who continued treatment in an extension study achieved an average weight loss of up to 30% after 104 weeks.
However, it’s important to note that these results are from clinical trials, meaning real-world outcomes could differ once, and if, retatrutide is approved.
Can you take weight loss medication while pregnant?
No, GLP-1 weight loss medicines like Mounjaro and Wegovy shouldn't be taken during pregnancy, while trying to conceive, or while breastfeeding, as there isn't enough safety data to rule out a risk to the baby.
If you're planning to get pregnant, you'll usually need to stop treatment in advance. If you become pregnant while taking any weight loss medication, stop treatment and speak to your GP or prescriber as soon as possible.
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