Weight loss injections often lead to greater weight loss than tablets. However, tablets are still a good choice for many. Mounjaro and Wegovy are injections that mimic gut hormones to cut appetite. Orlistat, a tablet, blocks fat absorption. Mysimba, another tablet, helps reduce cravings by acting on the brain.

Clinical trial data show that injections usually lead to more weight loss than tablets. However, the best option for you depends on your BMI, health history, and comfort with self-injection.

Keep reading for a complete comparison. You’ll see how each option works, what the data shows, and which one suits your needs.

What Are Weight Loss Injections?

Weight loss injections are prescription medicines. They are injected just under the skin. This can be done in the abdomen, thigh, or upper arm. Most options in the UK are given weekly with a pre-filled pen. This makes dosing easy after you learn how to use them.

They work by mimicking hormones your gut naturally produces after eating. The result is a lower appetite, slower digestion, and fewer food cravings. This leads to a clear drop in calorie intake over time. These are not a substitute for good eating and regular exercise. However, their clinical results are much better than older weight-loss treatments.

To qualify, you need a BMI of 30 or higher. If your BMI is 27 or more, you must also have a weight-related issue. These include high blood pressure, high cholesterol, sleep apnea, heart disease, prediabetes, or type 2 diabetes managed by diet. You also need to have already tried losing weight through diet and activity changes without reaching your goal.

There are age limits, and they differ between weight-loss treatments. One is available to adults up to 84; the other up to 74. Your pharmacist will confirm which applies.

Common Weight Loss Injections

Mounjaro (tirzepatide)

It targets two gut hormone receptors at once, GLP-1 and GIP, making it a dual-action treatment. It is a licensed weight loss injection in the UK. It is given once a week, and the dose is gradually increased from 2.5 mg to a maximum of 15 mg.

Wegovy (semaglutide)

This shot targets the GLP-1 receptor only and is given as a weekly injection. It was the first injectable GLP-1 medicine approved for weight management in the UK. It also has solid clinical evidence supporting its use. A higher 7.2 mg dose was approved in January 2026.

Saxenda (liraglutide)

This injection also works on the GLP-1 receptor but is injected daily rather than weekly. It is an older treatment with a longer safety track record. Results are more modest than Mounjaro or Wegovy, but it remains a licensed option where the others are not suitable.

Benefits and Side Effects of Weight Loss Injections

Benefits:

• Substantial average weight loss backed by large clinical trials
• Weekly dosing (daily for Saxenda) means less to remember than a tablet every day
• Appetite suppression tends to feel significant and consistent
• Improvements in blood sugar, blood pressure, and cardiovascular markers in many patients
• Works regardless of your dietary fat intake, unlike Orlistat

Common side effects:

• Nausea, particularly when the dose is first increased
• Vomiting or loose stools in some patients
• Reduced appetite can occasionally become too pronounced
• Injection site reactions (redness, itching, or mild bruising)
• Fatigue during the first few weeks of treatment

Side effects typically ease as the body adjusts. Gradual dose increases are used specifically to reduce the severity of early side effects. Most people who stay on treatment find them manageable within a few weeks.

Who these treatments are not suitable for

You cannot use injectable weight management treatments if you

• Are pregnant, trying to conceive, or breastfeeding
• Have or had an eating disorder
• Have a personal or family history of medullary thyroid cancer or MEN 2
• Have had pancreatitis
• Have type 1 diabetes
• Have severe kidney or liver disease
• Have a serious gut condition like Crohn’s disease or gastroparesis

They aren’t suitable if weight gain comes from another medical issue or your medication.

Storage Requirements

Injectable treatments must be stored in a refrigerator at a temperature between +2°C and +8°C.

What Are Weight Loss Tablets?

Weight loss tablets are oral prescription medicines taken daily by mouth. Unlike injections, they do not require any needles or injection techniques. Depending on the medicine, they either lower fat absorption from food or help the brain reduce hunger and cravings.

They usually cost less than injections. They are easier for patients who dislike needles or prefer taking tablets. Results are usually less dramatic than injections. However, they are still important for many patients, especially when paired with steady dietary changes.

Common Prescription Weight Loss Tablets

Orlistat 

It is the most common prescription weight loss pill in the UK. You can also buy it over the counter as Alli at a lower dose of 60 mg. It works in the gut by blocking the enzyme that breaks down dietary fat, reducing fat absorption by roughly a third. It does not affect appetite directly. For the best results with orlistat, it is important to follow a low-fat diet. High-fat meals can make side effects worse.

Mysimba (naltrexone and bupropion)

This contains two active ingredients that work on the brain’s reward and appetite pathways. Naltrexone is used in addiction medicine. Bupropion is used as an antidepressant and smoking cessation aid. Together, they reduce food cravings and the psychological urge to eat when not hungry. Mysimba is only available through private prescriptions in the UK. NICE did not recommend it for NHS use due to cost-effectiveness issues.

Benefits and Side Effects of Weight Loss Tablets

Benefits:

• No needles required
• More affordable than injectable treatments, particularly orlistat
• Orlistat is available over the counter at a lower dose without a prescription
• Tablets suit patients with needle aversion or who prefer a daily oral routine
• Mysimba works on cravings rather than fat absorption, which suit different eating patterns

Common side effects of Orlistat:

• Oily or fatty stools, urgency to use the toilet
• Flatulence with discharge
• Symptoms worsen significantly if a high-fat meal is eaten
• Reduced absorption of some fat-soluble vitamins (A, D, E, K)

Common side effects of Mysimba:

• Nausea, headache, dizziness, and insomnia are among the most frequently reported issues
• Some patients report mood changes, agitation, or restlessness
• Not for patients with a history of seizures, eating disorders, or specific psychiatric conditions.
• The EMA has flagged a potential long-term cardiovascular risk requiring ongoing monitoring

Weight Loss Injections vs Weight Loss Tablets: Key Differences

Effectiveness

The data gap between injections and tablets is significant and honest. In the SURMOUNT-1 trial, those taking Mounjaro 15 mg lost about 21% of their starting body weight in 72 weeks. Wegovy showed about 15% average weight loss in its key trials. The newer 7.2 mg dose reached around 18.7% average loss. In people who stuck to the plan, it rose to about 20.7%.

Orlistat leads to about 3% to 5% more weight loss than a placebo in most studies. Mysimba averages around 8.1% loss over 56 weeks in clinical studies. Both are worthwhile. Neither is close to what the injections deliver in the same period.

Speed of Weight Loss

Injections often show quicker results. They greatly reduce appetite in the first weeks of treatment. Tablets like orlistat rely on patients eating less dietary fat. This means that progress can vary more.

Ease of Use

Tablets are objectively simpler to take if needles are not your concern. No refrigeration is needed. No injection technique to learn. No sharps disposal to handle. Injections can be tricky at first. However, most patients find the weekly auto-injector pens easy to use after a few tries.

Safety Profile

Both options carry side effects, but they differ in character. Orlistat mainly causes gastrointestinal side effects tied to fat intake. You can manage these effects by adjusting your diet. Mysimba has more effects on the central nervous system. It is not recommended for many patients.

Injection-related side effects mostly impact the stomach when doses change, but they often fade away. The injections have been tested in larger groups for longer periods. This gives us more long-term safety data.

Long-Term Results

Weight regain after stopping is well documented. Trial follow-up data show that most people regain weight within a year after treatment ends. This happens unless they maintain changes in eating and activity. No medication works as a permanent fix without parallel lifestyle changes.

Cost Comparison

Orlistat is available over the counter at a lower dose. Mysimba is available on private prescription only in the UK. Wegovy is available on the NHS via specialist weight management services for eligible patients.

Prescription Requirements

All prescription-only treatments require a consultation with a qualified prescriber in the UK. Since 2025, you can’t just use a questionnaire to get a private prescription for weight loss injections. You now need a proper clinical assessment due to UK guidance on online weight-loss medicines. You now need a proper clinical assessment due to GPhC regulations. Orlistat 60 mg (Alli) is the only weight-loss aid you can get without a prescription; it comes in lower doses.

Which Treatment Is More Effective?

Injections produce more total weight loss on average. That is what the clinical data says, and there is no honest way to present it otherwise. Mounjaro and Wegovy are currently licensed weight-loss treatments in the UK.

That said, effectiveness is not the only relevant measure. An affordable, tolerable, and manageable treatment is better than a stronger option. If the stronger treatment fails after three months due to cost or side effects, it’s not worth it. For some patients, orlistat or myristic acid are the best choice, not just a compromise.

Who Should Choose Weight Loss Injections?

Injections are likely the better fit if

• Your BMI is 35 or above, or 30 or above with a weight-related health condition
• You need to lose a significant amount of weight, and speed matters for health reasons
• You are comfortable with self-injection or willing to learn
• You can manage the monthly cost privately, or you qualify for NHS access
• Dietary-only approaches have not produced enough progress over time

Our weight loss service in Liverpool offers consultations for Mounjaro and Wegovy. A pharmacist will check your eligibility and guide you through the treatment program.

Who Should Choose Weight Loss Tablets?

Tablets may suit you better if

• You have a significant fear of needles that affects adherence
• Your BMI is in the lower range, and moderate weight loss is the goal
• Budget is a genuine limiting factor, and injections are not affordable
• You prefer a simple daily oral routine
• You have already tried injections and found the side effects unmanageable
• You want an accessible starting point before considering injectable treatment

Lifestyle Changes That Improve Results

Neither injections nor tablets are a standalone solution. Clinical trials showed over 20% weight loss with Mounjaro. These trials included dietary support and increased physical activity in the program. Strip those out, and the results drop.

The basics matter:

• Eat less processed food
• Reduce portion sizes
• Move more each day; even walking counts
• Drink more water
• Get consistent sleep

These are not optional extras; they are what the medication is designed to work alongside.

If you stop one of these treatments without building sustainable habits, weight regain is likely. The medication can make the process easier. The habits are what make it last.

Frequently Asked Questions

Can you switch from weight loss tablets to injections if the tablets stop working?

Yes. Many patients begin with orlistat. After a clinical review, some switch to injectable treatment if they aren’t making enough progress. A prescriber should assess eligibility before switching.

What should I do if I need surgery or sedation?

If you are having an operation, an endoscopy, or any procedure involving sedation, tell the team you are on this treatment. It slows stomach emptying, and they need to know.

Do weight loss treatments affect contraception or pregnancy?

If you use the oral contraceptive pill, one of the injectable treatments can reduce how well the pill is absorbed. Use condoms or switch to a non-oral method for four weeks when you start. Do the same for four weeks after any dose increase. If you are planning to get pregnant, stop one of the treatments at least two months before.

What happens if I stop taking weight-loss injections or tablets suddenly?

Stopping treatment suddenly is usually safe. However, weight regain is common, especially with GLP-1 injections. A tapering plan is best for long-term treatments. Make sure to agree on this with your prescriber.

Are weight loss injections or tablets covered by the NHS in Liverpool?

Orlistat is available on the NHS via a GP or pharmacy. Wegovy is available through NHS specialist weight management pathways for eligible patients. Mounjaro on the NHS is limited to specific clinical settings. Private access to all options is available through pharmacies, including our weight management clinic.

Final Verdict: Weight Loss Injections vs Weight Loss Tablets

For the best weight loss, consider injections like Mounjaro and Wegovy. They are strong options if you qualify and have solid trial support.

Tablets are a good option for moderate weight loss. They work well if you want to avoid needles, can’t afford injections, or have health issues that make injections unsafe. Orlistat is backed by decades of safety data.

The best treatment is the one that fits your health profile, budget, and ability to stick with it. Neither option works in isolation; both need a lifestyle commitment for lasting results.

Talk to a provider before starting. At Orrell Park Pharmacy, our team can help you explore your options. We will also assess your eligibility. Book a consultation at our weight loss service or call us at 0151 525 1003.