Weight loss tablets: what actually works?

What do we mean by weight loss tablets?

When talking about weight loss tablets, it’s essential to separate two categories: prescription medicines and over-the-counter supplements. They differ in regulation, effectiveness, and safety.

1. Prescription medicines
These are prescribed by a doctor to treat obesity, or overweight with related health conditions.

Prescription weight loss medicines work through specific biological pathways. For example, they may affect hormones that regulate appetite (such as GLP-1) or reduce fat absorption in the gut.

2. Over-the-counter supplements
These are sold without a prescription, often online or in health shops. They’re typically marketed with claims about fat burning, appetite suppression, or rapid weight loss.

Unlike approved medicines, these products don’t go through the same rigorous clinical testing. Evidence for meaningful, long-term weight loss is usually limited. Safety is also less well understood.

Prescription vs over-the-counter options

There’s a clear difference in effectiveness between these two groups.

• Prescription options (e.g. Rybelsus, Mysimba, Orlistat):
These medicines are approved by regulatory authorities following extensive clinical trials. They’re used alongside lifestyle support, such as changes to diet, physical activity, and behaviour.

Studies show that, when combined with structured lifestyle changes, they can lead to clinically meaningful weight loss. Results vary depending on the treatment and the individual.

• Over-the-counter options (supplements):
These products are not held to the same regulatory standards. Common ingredients include caffeine, plant extracts, and fibre.

Some ingredients may have a small effect on appetite or energy levels, but results are usually modest and short-lived. Quality and content can also vary, and some products may carry risks, especially if taken in high doses or if they contain undisclosed substances.

If you’re considering treatment, it’s important to use trusted sources. Reputable online pharmacies in the UK will always require a prescription for medical weight loss tablets.

How do weight loss tablets work?

Prescription tablets for overweight and obesity work in different ways. The three main approaches are:

1. GLP-1 receptor agonist in tablet form (Semaglutide / Rybelsus)

Rybelsus contains semaglutide, the same active ingredient used in injectable treatments like Ozempic and Wegovy, but in tablet form.

How it works:
Semaglutide mimics a natural hormone (GLP-1) that helps regulate appetite.

It can:

• Increase feelings of fullness, helping you eat less
• Slow stomach emptying
• Support insulin release when needed

It’s used alongside a reduced-calorie diet and increased physical activity.

In the OASIS-1 study, people with obesity (without diabetes) lost around 15% of their body weight on average after 68 weeks with oral semaglutide 50 mg.

Read more about semaglutide in tablet form in our article on Rybelsus.

2. Acting on the brain’s reward system (Mysimba)

This medicine combines naltrexone and bupropion.

How it works:
It affects signals in the brain linked to hunger and reward, helping you feel full sooner and reduce food intake.

It may also help with:

• Food cravings
• Emotional eating
• Impulsive eating

This option may suit people whose eating patterns are strongly influenced by cravings or emotional triggers. It should always be part of a broader treatment plan, including lifestyle support.

3. Fat absorption blocker (Orlistat)

How it works:
Orlistat works in the digestive system by blocking enzymes that break down fat.

As a result:

• Around 30% of dietary fat isn’t absorbed
• The fat passes through the body instead

Unlike hormone-based treatments, it doesn’t affect appetite. Instead, it reduces calorie intake by limiting fat absorption.

It can support modest weight loss, especially when combined with a lower-fat diet and increased activity.

Who are weight loss tablets for?

Prescription treatment may be considered if you have:

• A BMI of 30 or above (obesity)
• A BMI of 27 or above (overweight) with at least one related condition, such as high blood pressure, type 2 diabetes, or raised cholesterol

These criteria are based on established medical guidelines and aim to reduce the risk of obesity-related conditions.

When might tablets be a good option?

Tablet treatment might suit you if you:

• Prefer to avoid injections, for example due to needle anxiety
• Travel often and want something that doesn’t need refrigeration
• Find a daily routine easier than weekly dosing

A doctor will always assess what’s suitable for you, taking into account your BMI, medical history, current medications, and personal preferences.

Common side effects and risks

It’s important to balance expected benefits with possible side effects. Always follow your doctor’s advice and attend regular follow-ups.

Most side effects are linked to how the medicine works and are often mild to moderate, especially at the start of treatment or when the dose is increased.

Common side effects may include:

• Nausea
• Diarrhoea or constipation
• Headache

Side effects by treatment

GLP-1 tablets (Rybelsus – semaglutide):

‍Most common are digestive symptoms:

• Nausea
• Constipation
• Diarrhoea

These are usually temporary and improve over time. Taking the medication correctly (on an empty stomach with a small amount of water, then waiting 30 minutes before eating) can help.

Rarely, inflammation of the pancreas (pancreatitis) has been reported. Seek medical advice if you have severe, ongoing abdominal pain.

Orlistat (Xenical):

‍Because it reduces fat absorption, it can cause digestive side effects, especially with higher-fat meals:

• Oily stools
• Gas
• Urgent bowel movements

Adjusting your diet can help reduce these effects.

Mysimba (naltrexone/bupropion):

‍Common side effects include:

• Nausea
• Headache
• Constipation
• Dizziness

Sleep disturbances can also occur. It isn’t suitable for everyone, including people with certain conditions such as epilepsy.

Individualised dosing

Treatment is usually started at a low dose and increased gradually if needed. The aim is to find the lowest effective dose that gives meaningful results while keeping side effects manageable.

Regular follow-up helps make sure the treatment is working well and remains safe.

Tablets vs injections for weight loss: what’s the difference?

Both forms can be effective.

• Rybelsus (tablet): Around 15% average weight loss after 68 weeks in studies (OASIS-1)
• Wegovy (injection): Around 15% average weight loss after 68 weeks (STEP-1 study)

For the right person, tablet treatment can be a very effective alternative to injections when used at the appropriate dose.

Diet and weight loss

Your eating habits play a key role in losing weight and maintaining results, even if you’re using medication.

A balanced diet with:

• Plenty of fruit and vegetables
• Whole grains
• Lean protein
• Healthy fats

…can support sustainable weight loss.

Try to limit sugar, salt, and saturated fats where possible.

Keeping a food diary or using an app can help you spot patterns and build awareness. Regular meals can also help prevent extreme hunger and overeating.

Long-term, sustainable changes are what make the biggest difference.

Physical activity and weight loss

Movement is an important part of treatment. It supports weight loss and helps maintain results over time.

Combined with medication, physical activity can:

• Help preserve muscle mass
• Improve metabolic health

Strength training is especially helpful for maintaining muscle, while cardio supports heart health, fitness, and energy levels.

You don’t need to do everything at once. Walking, cycling, swimming, light jogging, or group classes are all good options. The key is finding something that fits your routine and feels manageable.

A mix of strength and cardio is ideal, but start where you are and build gradually.

How Yazen supports you

With Yazen, you’re supported by a dedicated care team, including a doctor and a YazenCoach. Your coach may be a nurse, dietitian, or physiotherapist with experience in obesity treatment.

They support you throughout your journey with:

• Practical guidance on food and creating a sustainable calorie deficit
• Advice on physical activity tailored to your level
• Motivation and behaviour change strategies

Your doctor prescribes and adjusts medication as needed. Your treatment is regularly reviewed based on how your body responds, including changes in hunger, appetite, and eating patterns.

FAQs about weight loss tablets

Are tablets as effective as injections?

‍Modern GLP-1 tablets containing semaglutide have shown significant weight loss in clinical studies. At higher doses, results can approach those seen with injectable treatments.

In the OASIS-1 study, participants lost around 15% of their body weight after 68 weeks.

Effects depend on the dose and can vary between individuals. New oral treatments are also being developed, which may expand options in the future.

Are over-the-counter weight loss pills safe?

‍Safety varies widely. Most are classified as supplements and aren’t subject to the same standards as approved medicines.

If you need medical treatment for overweight or obesity, it’s recommended to use medicines approved by regulators and prescribed following a proper medical assessment.

How do I know what’s right for me?

‍A medical assessment is the best place to start. Your BMI, measurements, medical history, current medications, and preferences all play a role.

If you’d like to explore whether tablet-based treatment could work for you, Yazen can help you find an option that fits your needs and goals.

Sources

National Institutes of Health. Dietary supplements for weight loss: evidence and safety.
https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/

FDA. Avoiding products contaminated with hidden ingredients
https://www.fda.gov/drugs/medication-health-fraud/avoiding-products-contaminated-hidden-ingredients

European Medicines Agency (EMA). Clinical evaluation of medicinal products used in weight control
https://www.ema.europa.eu/en/clinical-evaluation-medicinal-products-used-weight-control-scientific-guideline

The New England Journal of Medicine. STEP 1 study
https://www.nejm.org/doi/full/10.1056/NEJMoa2032183

The Lancet. OASIS-1 study
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01185-6/abstract

Obesity journal. COR-II study
https://pubmed.ncbi.nlm.nih.gov/23408728/

European Medicines Agency (EMA). Mysimba
https://www.ema.europa.eu/en/medicines/human/EPAR/mysimba

European Medicines Agency (EMA). Xenical
https://www.ema.europa.eu/en/medicines/human/EPAR/xenical

European Medicines Agency (EMA). Rybelsus
https://www.ema.europa.eu/en/medicines/human/EPAR/rybelsus

European Heart Journal. Obesity and cardiovascular disease
https://doi.org/10.1093/eurheartj/ehae508

The New England Journal of Medicine. Orforglipron
https://www.nejm.org/doi/full/10.1056/NEJMoa2511774