Wegovy and Mounjaro both are weekly injections and two of the most effective prescription weight loss injections available in the UK right now. Both are MHRA approved and available privately without a GP referral.
The difference comes down to mechanism, results, and what your body actually needs.
Mounjaro works on two appetite-regulating hormones, GLP-1 and GIP, while Wegovy works only on GLP-1. The first-ever head-to-head clinical trial (SURMOUNT-5, NEJM May 2025) found Mounjaro produced 20.2% average weight loss versus 13.7% with Wegovy over 72 weeks. That’s roughly 47% more.
But on the other hand, Wegovy has a 20% proven reduction in heart attacks and strokes from the SELECT trial. Mounjaro doesn’t have this and is crucial for men with cardiovascular risk.
What’s right for you? That depends on your weight loss goal, your health history, and for men specifically, what visceral fat is doing to your testosterone, your heart, and your metabolic baseline. We'll cover all of this.
Key Takeaways
- Both Wegovy and Mounjaro are once-weekly injections, MHRA-approved, and available privately through HeMed without a GP referral.
- The first direct head-to-head trial (SURMOUNT-5, NEJM 2025) found tirzepatide produced 20.2% average weight loss vs 13.7% with semaglutide at 72 weeks — about 47% more.
- Side effect profiles are similar. Mounjaro may cause slightly more nausea early on; Wegovy (semaglutide) slightly more constipation. Both are well-tolerated by the majority of patients.
- Wegovy has a clinically proven cardiovascular benefit: the SELECT trial showed a 20% reduction in major cardiac events.
- For men, Mounjaro's stronger visceral fat reduction and greater total weight loss are clinically meaningful, particularly for testosterone recovery and metabolic health.
- You cannot take both at the same time. Switching between them is possible but requires clinical guidance.
- HeMed prescribes both. First month only from £59, including blood test.
What Are Wegovy and Mounjaro?
What is Wegovy?
Wegovy contains an active ingredient called semaglutide, a GLP-1 receptor agonist developed by Novo Nordisk. GLP-1 (glucagon-like peptide-1) is a hormone that your gut releases after eating, signalling your brain to reduce hunger and increase fullness. Semaglutide mimics this hormone in an amplified manner. Ozempic is a lower-dose version of the same.
Wegovy is the higher-dose formulation (up to 2.4 mg, or the new 7.2 mg dose) licensed specifically for weight management. It's been available in the UK since 2023.
For eligibility detail, read our Wegovy guide for men.
What is Mounjaro?
Mounjaro, developed by Eli Lilly, contains tirzepatide, a dual-action receptor agonist that works on GLP-1 and GIP appetite regulating hormones. GIP (glucose-dependent insulinotropic polypeptide) works alongside GLP-1 to enhance fat metabolism and energy processing. This additional mechanism is why Mounjaro tends to produce greater average weight loss.
Mounjaro was approved by the NHS in December 2024, but access remains limited.
For the full picture, see our Mounjaro for men guide.
Wegovy vs Mounjaro: How Much Weight Will You Lose?
What data shows
Before May 2025, a direct comparison was difficult as no study showed directly comparable results because of there being two different mechanisms and dosages. So, clinicians compared these drugs across separate trials with different patient populations.
- Wegovy (STEP 1 trial, NEJM 2021): average 15.8% body weight loss over 68 weeks at 2.4 mg
- Mounjaro (SURMOUNT-1 trial, NEJM 2022): average 20–22% body weight loss at 15 mg over 72 weeks
The SURMOUNT-5 trial: the first direct comparison
The head-to-head comparison got published in the New England Journal of Medicine on 12 May 2025. SURMOUNT-5 was the first phase 3b randomised controlled trial to compare tirzepatide and semaglutide in the same patients, at the same time, under the same conditions. 751 adults with obesity but without type 2 diabetes. Maximum tolerated dose of each drug. 72 weeks.
The result:
- Tirzepatide (Mounjaro): 20.2% average weight loss
- Semaglutide (Wegovy): 13.7% average weight loss
- Tirzepatide participants more likely to reach every weight-loss threshold — ≥10%, ≥15%, ≥20%, and ≥25%
- GI side effects were common in both groups but led to discontinuation in only 3% on tirzepatide and 6% on semaglutide
Mark, a 48-year-old engineer from Manchester -
He started on Wegovy in early 2024 and lost 11% of his body weight over seven months. It was solid, but had plateaued. His HeMed clinician reviewed his blood results and switched him to Mounjaro under clinical guidance. Eight months later he'd lost a further 12%. His total loss: over 20% of his starting weight.
Side Effects: Wegovy vs Mounjaro
The common ones
Because both act on GLP-1 receptors, the side effect profile is fundamentally similar. You can expect -
- Nausea (most common, especially in the first weeks and around dose step-ups)
- Constipation
- Diarrhoea
- Stomach discomfort, bloating, or reflux
- Reduced appetite (obviously)
Side effects are usually mild to moderate and tend to improve as your body adjusts. The slow dose escalation on both medications helps manage them.
🔗 NICE — Technology Appraisal TA875 (tirzepatide) | MHRA Wegovy prescribing information
Where they differ
Some men experience more nausea on Mounjaro, probably because of its dual-hormone action. Constipation, on the other hand, appears slightly more common with semaglutide. Only 3% sample population with tirzepatide and 6% with semaglutide discontinued due to side effects as per the SURMOUNT-5 study.
Neither medication causes hypoglycaemia on its own, though this becomes a risk when combined with insulin, sulphonylureas, or glinides. Both carry a small risk of pancreatitis and gallbladder issues. Neither is suitable for anyone with a personal or family history of medullary thyroid carcinoma or MEN2 syndrome.
Talk to a Clinician
If you experience severe abdominal pain spreading to the back, sudden vision changes, or signs of an allergic reaction on either medication, stop and seek urgent medical advice.
HeMed clinicians are available for support throughout your programme, that's what the clinical oversight is for. You don't need to tough it out alone.
Wegovy vs Mounjaro Cost in the UK
Both Wegovy and Mounjaro are available privately in the UK without a GP referral. The cost usually increases as your dose does. But here at HeMed, we offer flat pricing. This means that your monthly cost stays consistent regardless of which dose you're on. We know that these medications can occupy a significant chunk of your monthly budget. We just want to help you plan it better.
HeMed programmes start from £59 for your first month (Spring Sale; normally £139), with your blood test and side-effect care pack included. Ongoing pricing from £159/month for Wegovy and from £299/month for Mounjaro.
On pure monthly cost, Wegovy is the more affordable option. The what you need to ask here is, if Mounjaro produces meaningfully greater weight loss and gets you to your target faster, does the higher monthly cost work out to a similar, or even lower total spend?
Straight Talk on Cost
HeMed saves members up to £1,000 a year vs providers who charge more as doses increase. If you're switching from another provider, you can continue at your current dose without starting again.
See current pricing at hemed.com/pricing, or speak to a clinician to understand which option makes sense for your situation.
Wegovy vs Mounjaro: Which is best for you?
Who is Wegovy best suited for?
Wegovy has a longer clinical track record in the UK and an additional cardiovascular benefit which can be a real difference for some men. The SELECT trial with 17,604 patients, published in the NEJM and analysed further in The Lancet in October 2025, showed that semaglutide reduced major adverse cardiovascular events (heart attack, stroke, cardiovascular death) by 20%. This benefit was irrespective of the weight loss.
This makes Wegovy a better option for -
- Men with established cardiovascular disease or elevated CVD risk
- Those who previously used Ozempic for diabetes and tolerated semaglutide well
- Those who find the dual action of Mounjaro a bit too much to tolerate
- Those for whom monthly cost is a significant deciding factor.
Who is Mounjaro best suited for?
Mounjaro is best for men for whom maximum weight loss is the first priority, particularly for ones with significant visceral fat, those whose body haven’t responded sufficiently to Wegovy or semaglutide, or those whose metabolic profile is more suited for Mounjaro’s dual-hormone action.
The SURMOUNT-MMB trial demonstrated meaningful cardiovascular and metabolic benefits with tirzepatide, the active ingredient in Mounjaro. A meta-analysis published in PubMed 2025 also confirmed tirzepatide's superiority to semaglutide across multiple direct comparative studies.
Wegovy vs Mounjaro for men specifically
Men carry proportionally more visceral fat (the fat surrounding internal organs) than women at equivalent BMI levels. Visceral fat is one of the most contributing factors that drive cardiovascular risk, insulin resistance, low testosterone, and sleep apnoea. Both medications reduce it. Mounjaro reduces it more.
Men on GLP-1 medications who achieve a 10% weight reduction have shown testosterone increases of 53–77% over 18 months. The greater the weight loss, the stronger the hormonal recovery. Mounjaro's superior weight loss figures make it the stronger lever for men where testosterone and metabolic health are part of the picture.
The Elephant in the Room: Why Men Delay Starting
Despite representing the majority of those classified as obese with high metabolic risk men make up only around 30% of NHS weight management referrals. We’ve seen some men associating injectable weight loss medication with giving up or not for them. That’s both, outdated and medically wrong.
Obesity has a strong genetic and hormonal component. For men, where androgen levels influence fat distribution and metabolic rate, that’s more applicable. Wegovy and Mounjaro target the hormonal system that regulates appetite, making them a clinical intervention for a clinical problem, not a shortcut.
Other point that we often come across is that men tend to delay until health complications have already arrived. This includes high blood pressure flagged at a routine check, a GP mention of pre-diabetes, or a family history of heart disease starting to feel real. Both medications reduce visceral fat directly. And earlier treatment means faster improvement in the markers that matter.
HeMed is a health programme specially made for men. We understand the barriers you face. Our clinicians are used to the conversation. You don't need to have it all worked out before you get in touch.
Can I Switch Between Wegovy and Mounjaro?
Switching from Wegovy to Mounjaro
Yes, but only under medical supervision and it's one of the most common reasons men come to HeMed. Men mostly think of switching only because of two reasons -
- Not hitting target weight loss on Wegovy, wanting to try the dual-mechanism approach
- Or reaching a plateau in the weight loss journey.
Because the two medications use different dosing scales and mechanisms, switching is not a direct swap. A clinician needs to review your current dose, progress, and health picture, to advise on timing and starting dose for Mounjaro.
Switching from Mounjaro to Wegovy
Again, it’s possible but should be done only under medical guidance. Here, the most common driver is cost. Prices for Mounjaro increased significantly in 2024 and this made many men think that Wegovy's weight-loss profile is sufficient for their goals at a lower monthly spend.
Can you take both at the same time?
Strictly No. While both medications target GLP-1 receptors, taking them together provides no additional clinical benefit. It can increase the risk of side effects significantly.
HeMed Prescribes Both. Let a Clinician Help You Choose
You don't have to decide between Wegovy and Mounjaro on your own.
At HeMed, every programme starts with a mandatory at-home blood test and clinician review. We look at your metabolic markers, health history, and goals, then recommend the right medication, at the right dose, for you.
First month only from £59 (Spring Sale normally £139).
Blood test included. 100,000+ members.
Start your consultation: hemed.com
Already with another provider? Switch to HeMed and save up to £1,000/year:
Blue Light Card (NHS and emergency services): 20% discount.
Frequently Asked Questions
Is Mounjaro better than Wegovy for weight loss?
In the first direct head-to-head trial (SURMOUNT-5, NEJM 2025), tirzepatide produced 20.2% average weight loss versus 13.7% with semaglutide over 72 weeks. Mounjaro's dual GIP and GLP-1 mechanism targets two appetite-regulating hormones rather than one. That said, both are highly effective, and the right choice depends on your health profile, history, and goals. A HeMed clinician assessment will help you land on the right one.
What are the side effects of Wegovy vs Mounjaro?
Side effects are similar with both medications. They include nausea, diarrhoea, constipation, and stomach discomfort, that are most common initially and around dose increases. Mounjaro may cause slightly more nausea early on and Wegovy slightly more constipation. But SURMOUNT-5, discontinuation due to side effects was 3% on tirzepatide and 6% on semaglutide.
How much does Wegovy cost vs Mounjaro in the UK?
Both are available on private prescription. At HeMed, Wegovy starts from £159/month (after your first month at £59) and Mounjaro from £299/month, with flat pricing across all doses, which is unusual in the market. Some providers charge more as doses increase; HeMed doesn't.
Is Wegovy or Mounjaro available on the NHS?
Wegovy is available via specialist weight management referral on the NHS. Mounjaro received NHS approval in December 2024 but access remains very limited. In England, prescribing is restricted to GP practices meeting specific criteria. Both are available privately through HeMed without a GP referral.
What is the best weight loss injection for men?
The head-to-head data favours Mounjaro for total weight loss, particularly visceral fat reduction which is important for men's metabolic and hormonal health. Wegovy's, on the other hand, has clinically proven cardiovascular benefits. Neither is universally "the best". It depends on what you're optimising for. HeMed’s blood test and clinical assessment can help determine the best for you.
Sources
HeMed is a clinically-led, UK-based weight management programme for men. All clinicians are UK-registered. Pharmacy partner: eMed Healthcare UK (GPhC-registered, CQC-regulated). This article is for information only and does not constitute medical advice. Always consult a qualified clinician before starting or changing any treatment.
HeMed’s personalised weight loss programme uses medical treatment to help you achieve results that last.
