Mounjaro vs Saxenda

Jump to: Quick comparison | How do Mounjaro and liraglutide work? | Weight loss: what the evidence shows | Side effects and tolerability | Dosing and practical differences | Cost and access in the UK | Who might prefer each option? | FAQs | Take home message

Mounjaro (tirzepatide) produces significantly more weight loss than Saxenda (liraglutide).

In clinical trials, tirzepatide led to 15–22.5% average weight loss over 72 weeks, compared with 8% average weight loss with liraglutide 3.0 mg over 56 weeks.^1,2

The two medications work differently. Mounjaro targets two hormone receptors (GLP-1 and GIP), while Saxenda targets only one (GLP-1). This dual action is likely why Mounjaro leads to more weight loss.

If you’re searching for this comparison, it’s worth knowing that Saxenda has been discontinued by Novo Nordisk.

The branded product is no longer manufactured, though a generic version of liraglutide, called Nevolat, is now available in the UK from various pharmacies.

If you’re currently taking liraglutide and considering your options, or you’re comparing these medications for the first time, this guide covers the clinical evidence, side effects, practical differences, and cost to help you make an informed decision.

Mounjaro vs Saxenda: quick comparison

How do Mounjaro and liraglutide work?

When we eat, our gut releases hormones that regulate hunger and blood sugar.

One of the most important is GLP-1 (glucagon-like peptide-1), which slows digestion, reduces appetite, and helps the pancreas release insulin.

Our body breaks down natural GLP-1 very quickly, within minutes of its release. Both Mounjaro and liraglutide resist this breakdown, so their effects last much longer.

How liraglutide (Saxenda/Nevolat) works

Liraglutide mimics GLP-1 only. It slows gastric emptying, communicates with the brain’s appetite control centre to reduce hunger, and improves blood sugar levels.

Because liraglutide is cleared from the body relatively quickly compared with newer GLP-1 medications, it needs to be injected every day.

How Mounjaro works

Mounjaro mimics two hormones: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide).

GIP is another gut hormone released after eating. It helps regulate blood sugar, supports how the body stores excess energy in fat tissue (rather than in the liver or pancreas), and has receptors in the brain that appear to help us feel fuller for longer.

This dual-action approach is the most likely explanation for why Mounjaro produces greater average weight loss than single-action GLP-1 medications like liraglutide.¹

Tirzepatide also stays active in the body for longer than liraglutide, which is why it only needs to be injected once a week.

Key points:

• Liraglutide (Saxenda/Nevolat) mimics one hormone (GLP-1) to reduce appetite and improve blood sugar control
• Mounjaro mimics two hormones (GLP-1 and GIP), providing additional appetite regulation and metabolic benefits
• Mounjaro is injected weekly; liraglutide is injected daily
• Both medications are manufactured to resist the body’s natural breakdown of GLP-1, allowing their effects to last longer than the natural hormone

Weight loss: what the evidence shows

Clinical trial data

There is no direct head-to-head trial comparing tirzepatide with liraglutide for weight loss.

However, large clinical trials have tested each medication individually against a placebo, and the results are informative.

Liraglutide 3.0 mg (SCALE Obesity and Prediabetes trial):

The SCALE trial enrolled 3,731 adults without type 2 diabetes. After 56 weeks, participants taking liraglutide 3.0 mg lost an average of 8.4 kg (approximately 8% of body weight), compared with 2.8 kg in the placebo group.²

63.2% of participants on liraglutide lost at least 5% of their body weight, and 33.1% lost more than 10%.²

Tirzepatide (SURMOUNT-1 trial):

The SURMOUNT-1 trial enrolled 2,539 adults without type 2 diabetes. After 72 weeks, average weight loss was:¹

• 5 mg dose: 15.0% (16 kg)
• 10 mg dose: 19.5% (22 kg)
• 15 mg dose: 20.9% (24 kg)

89–96% of participants on tirzepatide lost at least 5% of their body weight, and over a third on the highest dose lost 25% or more.¹

Important context when comparing these numbers

These trials were conducted at different times, in different populations, and over different durations (56 weeks for SCALE vs 72 weeks for SURMOUNT-1). Directly comparing the percentage figures requires some caution.

That said, the difference is substantial enough that most clinicians and researchers agree that tirzepatide produces significantly more weight loss than liraglutide.

A 2025 cost-effectiveness analysis published in the Journal of Managed Care & Specialty Pharmacy confirmed that tirzepatide was more effective and more cost-effective than liraglutide for obesity management.³

Real-world data with behavioural support

Second Nature’s peer-reviewed research, published in JMIR Formative Research (2025), showed that tirzepatide combined with registered dietitian support and a structured behaviour change programme produced 22.1% average weight loss at 12 months, with 95.2% of participants achieving at least 10% weight loss.⁴

This exceeded the results of the SURMOUNT-1 clinical trial, suggesting that comprehensive behavioural support may enhance medication outcomes.

No real-world data on liraglutide combined with a similar structured support are available, so a direct comparison between the two medications is not possible.

Key points:

• In clinical trials, tirzepatide (Mounjaro) produced roughly double the average weight loss of liraglutide (Saxenda), though these were separate trials with different durations
• Tirzepatide at the 15 mg dose produced approximately 21% average weight loss over 72 weeks
• Liraglutide 3.0 mg produced approximately 8% average weight loss over 56 weeks
• Real-world data from Second Nature shows even greater results (22.1%) when tirzepatide is combined with behavioural support

Side effects and tolerability

Both medications share a similar side-effect profile, predominantly affecting the gastrointestinal tract.

Most side effects are mild to moderate and tend to improve as the body adjusts.

Common side effects

The most frequently reported side effects for both medications include nausea, vomiting, diarrhoea, and constipation. These typically occur during the initial weeks of treatment or during dose increases.

In the SCALE trials, the most common adverse events with liraglutide were nausea and diarrhoea. Serious adverse events occurred in 6.2% of liraglutide participants, compared with 5.0% on placebo.²

In the SURMOUNT-1 trial, 25.9% of tirzepatide participants experienced nausea, and 4.3–7.1% discontinued due to adverse events (depending on dose).¹

Discontinuation rates

Clinical trial data suggest a higher proportion of participants discontinue liraglutide due to side effects compared with tirzepatide.

Some earlier studies reported discontinuation rates of up to 27% with liraglutide, compared with 5–10% with tirzepatide.

Side effects improve over time

Second Nature’s published research found that side effects with tirzepatide decreased substantially over 12 months:⁴

• Nausea dropped from 27.8% at month 1 to 10.5% by month 12
• Fatigue dropped from 21.5% at month 1 to 8.1% by month 12
• By month 12, 60.3% of tirzepatide users reported no side effects

Long-term real-world side-effect tracking data for liraglutide are limited, though clinical trials showed a similar pattern of improvement over time.

Safety considerations for both

Neither medication should be used if you have a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Both medications can affect the absorption of oral medications by slowing gastric emptying. If you take other medications, discuss potential interactions with your prescriber.

Liraglutide has a longer overall safety track record, having been approved for weight management since 2015, compared with tirzepatide, which was approved in 2023.

Key points:

• Both medications cause similar gastrointestinal side effects, most commonly nausea, diarrhoea, and constipation
• Side effects tend to occur early in treatment and improve over time
• Tirzepatide appears to have lower discontinuation rates due to side effects than liraglutide
• Liraglutide has a longer safety track record (approved 2015 vs 2023 for tirzepatide)

Dosing and practical differences

Injection frequency

One of the most significant practical differences is how often you inject.

Mounjaro is injected once per week. Many people prefer this because it’s easier to fit into a routine and involves fewer injections overall.

Liraglutide (Saxenda/Nevolat) is injected once per day. While some people are comfortable with daily injections, others find the frequency inconvenient or difficult to maintain, particularly when travelling.

Dose escalation

Mounjaro starts at 2.5 mg weekly, increasing by 2.5 mg every four weeks. There are three possible maintenance doses: 5 mg, 10 mg, and 15 mg. This flexibility means you and your prescriber can find the dose that balances effectiveness with tolerability.

Liraglutide starts at 0.6 mg daily, increasing by 0.6 mg each week over five weeks until reaching the maintenance dose of 3.0 mg. There is only one maintenance dose, offering less flexibility.

Storage

Both medications should be stored in the fridge (2–8°C) before first use.

• Mounjaro: Once in use, it can be kept at room temperature (below 30°C) for up to 21 days
• Liraglutide: Once in use, it can be kept at room temperature (below 30°C) for up to 30 days

Neither medication should be frozen. Both can be carried in hand luggage for travel.

Missed doses

Mounjaro: If you miss a dose and there are at least 4 days until your next scheduled dose, take it as soon as you remember. Otherwise, skip the missed dose.

Liraglutide: If you miss a dose, skip it and take your next dose at the usual time the following day. Do not take a double dose.

Injection technique

Both use pre-filled pens and are injected subcutaneously (under the skin) into the stomach, thigh, or upper arm. Rotate injection sites to reduce irritation.

Cost and access in the UK

Private prescription costs

Costs vary by provider and depend on the dose you’re taking.

Mounjaro typically costs between £200 and £350 per month through private providers, depending on the dose and what’s included in the service. Some providers include clinical support and behavioural coaching, while others charge for the medication only.

Generic liraglutide (Nevolat) is significantly cheaper, typically costing between £70 and £160 per month from UK online pharmacies. Branded Saxenda is no longer being manufactured.

When comparing costs, it’s worth considering what you’re getting alongside the medication. Research consistently shows that medication combined with structured support produces better outcomes than medication alone.⁴

Saxenda has been discontinued

Novo Nordisk has discontinued production of Saxenda to focus manufacturing capacity on newer medications like Wegovy.

In the UK, branded Saxenda is now long-term out of stock.

A generic version of liraglutide, called Nevolat (manufactured by Zentiva), is widely available in the UK as a direct replacement.

It contains the same drug at the same doses, so there is no clinical difference between the two.

If you’re currently taking Saxenda and your supply has been affected, speak with your prescriber about switching to Nevolat, or about whether a different medication, such as Mounjaro or Wegovy, might be more appropriate.

NHS availability

Both medications are theoretically available through NHS specialist weight management services (Tier 3 and Tier 4), though access remains limited.

Eligibility typically requires a BMI of 35 or above (or 30+ with weight-related conditions), documented attempts at weight loss, and a referral to specialist services. Waiting times vary significantly by region.

NICE has published guidance recommending tirzepatide for obesity management alongside lifestyle modification, with no maximum treatment duration.⁵

Who might prefer each option?

Individual responses to medications vary significantly, and the right choice depends on your personal circumstances.

Liraglutide (Nevolat) might be preferred if:

• Cost is a primary concern. Generic liraglutide is substantially cheaper than Mounjaro.
• You’ve previously responded well to liraglutide. If Saxenda has worked for you and you’re comfortable with it, switching to Nevolat keeps you on the same medication at a lower cost.
• You prefer a medication with a longer safety track record. Liraglutide has been used for weight management since 2015, providing over a decade of safety data.
• You’re looking for a lower-intensity option. For some people, the moderate weight loss associated with liraglutide may be appropriate for their goals.

Mounjaro might be preferred if:

• You want the most effective available option at standard doses. Clinical trials consistently show that tirzepatide produces significantly greater weight loss than liraglutide.
• You prefer weekly injections. One injection per week is more convenient than daily.
• You have type 2 diabetes alongside obesity. Mounjaro’s dual-action mechanism provides particularly strong blood sugar control.
• You want dosing flexibility. Three maintenance dose options allow you and your prescriber to find the right balance.
• You’ve tried liraglutide but haven’t achieved the desired results. The different mechanisms offer an alternative approach.

Frequently asked questions

Is Saxenda still available in the UK?

Branded Saxenda has been discontinued by Novo Nordisk and is no longer being manufactured.

However, a generic version of liraglutide called Nevolat (made by Zentiva) is widely available through UK pharmacies. It contains the same drug and works in exactly the same way.

Can I switch from Saxenda or Nevolat to Mounjaro?

Yes. If you’re currently taking liraglutide and want to switch to Mounjaro, speak with your prescriber.

Because liraglutide is cleared from the body relatively quickly, you can typically start Mounjaro without a long waiting period, though your prescriber will advise on timing and the appropriate starting dose.

Why is Mounjaro weekly but Saxenda daily?

The difference comes down to how long each medication stays active in the body. Tirzepatide (Mounjaro) has been engineered to have a much longer half-life than liraglutide, meaning it maintains effective levels in the body for about a week. Liraglutide is broken down more quickly and needs daily dosing to maintain its effects.

Is liraglutide the same as Nevolat?

Yes. Liraglutide is the drug in Nevolat.

Nevolat is the brand name for a generic version of liraglutide, replacing the now-discontinued Saxenda. Both contain the same medication at the same concentration.

Do you lose more weight on Mounjaro or liraglutide?

On average, significantly more weight is lost on Mounjaro. Clinical trials showed approximately 15–21% weight loss with tirzepatide over 72 weeks, compared with approximately 8% with liraglutide over 56 weeks.^1,2

However, individual responses vary, and some people respond well to liraglutide.

Is Mounjaro safer than liraglutide?

Both medications have acceptable safety profiles, with similar side effects, mainly gastrointestinal. Liraglutide has a longer safety track record (approved since 2015).

Tirzepatide appears to have lower rates of treatment discontinuation due to side effects in clinical trials. Neither has shown significant safety concerns when prescribed appropriately.

How long do I need to take these medications?

Current guidance from NICE treats obesity as a chronic condition and recommends treatment for at least 12 months, with potential continuation if it remains safe and effective.⁵

Research shows that significant weight regain commonly occurs when stopping medication without having established sustainable habits.

Will I gain weight back if I stop?

Some weight regain is common after stopping either medication if sustainable habits have not been established. Clinical trials with GLP-1 medications show that people typically regain a significant proportion of lost weight within a year of stopping, without ongoing support.⁶

This is one reason why combining medication with structured behavioural support, rather than taking medication alone, may produce more lasting results.

Can I take liraglutide and Mounjaro together?

No. You should not take two GLP-1 medications at the same time. If you’re switching from one to the other, your prescriber will advise on the appropriate timing.

Does either medication interact with the contraceptive pill?

Both medications can slow gastric emptying, which may affect how quickly oral medications (including the contraceptive pill) are absorbed.

If you take oral contraception, discuss with your prescriber whether alternative contraceptive methods might be advisable during the first few months of treatment. There is no evidence of interaction with contraceptive patches or injections.

Take home message

Mounjaro (tirzepatide) produces significantly more weight loss than liraglutide (Saxenda/Nevolat) in clinical trials: approximately 15–21% versus 8% over similar timeframes.^1,2

Mounjaro also offers practical advantages, including weekly rather than daily injections and more flexible dosing options.

Liraglutide remains a viable option for people who are cost-sensitive, have responded well to it previously, or prefer a medication with a longer safety history. With Saxenda discontinued, Nevolat provides the same medication at a lower price.

Research consistently shows that weight-loss medications are most effective when combined with structured support that helps you build sustainable habits.

Taking medication alone can produce significant short-term weight loss, but maintaining that weight loss after stopping typically requires the healthy eating patterns and behaviours developed alongside the medication.^4,6

References

1. 1. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022;387(3):205-216. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
   2. Pi-Sunyer X, Astrup A, Fujioka K, et al. A randomized, controlled trial of 3.0 mg of liraglutide in weight management. N Engl J Med. 2015;373(1):11-22. https://www.nejm.org/doi/full/10.1056/NEJMoa1411892
   3. Liu L, Cui J, Neidecker MV, Nahata MC. Tirzepatide vs semaglutide and liraglutide for weight loss in patients with overweight or obesity without diabetes: a short-term cost-effectiveness analysis. J Manag Care Spec Pharm. 2025;31(5):441-450. https://www.jmcp.org/doi/10.18553/jmcp.2025.31.5.441
   4. Richards R, Lunt W, Whitman M, et al. Semaglutide and tirzepatide in a remote weight management program: 12-month retrospective observational study. JMIR Form Res. 2025;9:e81912. https://formative.jmir.org/2025/1/e81912
   5. National Institute for Health and Care Excellence. Tirzepatide for managing overweight and obesity (TA1026). 2024. https://www.nice.org.uk/guidance/ta1026
   6. West J, Sheringham J, Roberts N, et al. Weight regain after cessation of medication for weight management: systematic review and meta-analysis. BMJ. 2026;392:e085304. doi:10.1136/bmj-2025-085304