Appetite Suppressants

Finding ways to control our diets and cravings can be challenging. You may have heard about appetite suppressants and be wondering what they are, if and how they work, and whether they may be right for you.

You can find out everything you need to know about appetite suppressants in this article from how they work and who can use them to side effects and safety.

Appetite suppressants are medications or supplements that make you feel less hungry and help you feel full faster. They work by changing or blocking processes in the body that control hunger, appetite, and energy.

Medicated appetite suppressants are available as tablets or injections, and usually require a prescription from a doctor or a pharmacist. However, some are available over the counter without a prescription.

The main purpose of appetite suppressants is to help people with obesity, which is classified as having a body mass index (BMI) equal to or over 30. Appetite suppressants work to reduce the amount you eat which can help with weight loss, especially if you’re struggling to do so with diet and exercise alone. People may use appetite suppressants as part of their weight loss journey to help reduce cravings and temptations and to consume fewer calories (kcal) overall.

Most prescription appetite suppressants (injections like Wegovy, Mounjaro, and Nevolat) work by mimicking the effects of a naturally occurring hormone in your body called glucagon-like peptide-1 (GLP-1), which is responsible for controlling your appetite.

They help you lose weight by:

• reducing your appetite
• slowing down how long it takes for food to leave your stomach
• regulating your blood sugar levels

This reduces feelings of hunger and increases how satisfied or full you feel after eating a meal.

Other appetite suppressants may work in a different way, such as Mysimba, which targets the parts of your brain that control food intake, appetite, and energy levels.

Yes, studies show that appetite suppressants can help with weight loss by reducing hunger, which lowers caloric intake (how many calories you eat in a day). The best and most preferred way to lose weight is by reducing the total number of calories you eat in a day by around 600 calories from the suggested total. As a guide:

• an average man needs 2,500kcal a day
• an average woman needs 2,000kcal a day

However, it is important to know that appetite suppressants are medications that work best as just one aspect of your weight loss process. To see the best weight loss results, you should use appetite suppressants in addition to exercise, a healthy diet, and lifestyle changes.

There are a range of different types of appetite suppressants available, including prescription and over-the-counter options. Prescription treatments are typically available in the form of injections and tablets. Over-the-counter appetite suppressants are typically available as oral tablets – these may be less effective as there is limited evidence for how well they work.

If you feel medication is not right for you but want to reduce your appetite and cravings, there are also natural ways to suppress your appetite.

Prescription appetite suppressants

Medications for weight loss and appetite suppression are available in the UK with a prescription from registered healthcare professionals like your GP or regulated online services like ZAVA.

These medications can be very effective appetite suppressants that help you to lose weight by reducing hunger and therefore, your calorie intake. Due to the way that these treatments work, you would first need a consultation with a doctor so that they can ensure your eligibility and that they are safe and suitable for you.

Please note that these treatments are most effective when taken alongside a balanced diet and regular exercise.

Prescription appetite suppressants include:

Some appetite suppressants are available without the need for a prescription and can be found online or in stores. Usually, these are food supplements that may improve results in reducing appetite and weight loss. However, there is little evidence that these supplements are highly effective and many should be used with caution as they can be unsafe for some people.

Non-prescription appetite suppressants include:

Certain foods may have properties which can naturally suppress the appetite. This might be a good option for those looking to reduce their appetite and lose weight without medication or supplements.

Natural appetite suppressants include:

Yes, appetite suppressants are generally safe when taken under medical advice and supervision. With prescription appetite suppressants, a registered healthcare professional will ensure that the medication is safe and appropriate for you and your individual health needs before recommending it. These medications are also subject to testing and regulation in the UK to ensure that they are safe and effective.

Despite this, there are some safety concerns around the use and misuse of appetite suppressants, prescription and over-the-counter. Concerns include:

Misuse

Appetite suppressants are designed for people who are overweight or obese and can be unsafe if misused. Doctors will assess your eligibility and potential for misuse before prescribing appetite suppressants.

Weight loss injections like Mounjaro, Nevolat, and Wegovy follow a gradually increasing dosage schedule to allow your body to adjust to the medications over time. If used incorrectly, they can be unsafe and cause severe side effects.

Long-term safety

Long-term use of appetite suppressants, both prescription and supplements, requires caution. For example, glucomannan can cause bloating and stomach pain due to its high fibre content.

The long-term safety of weight loss injections is still being studied, though they have been shown to be safe for short-term use up to 2 years.

UK regulations and safety

Some appetite suppressants have been banned in the UK because of safety concerns and lack of efficacy, including diethylpropion hydrochloride and phentermine hydrochloride. These medications may be available ‘off-license’ on private prescriptions from so-called “slimming clinics” but they are not recommended.

The newly-approved and regulated weight loss injections, such as Mounjaro or Wegovy, are a safer and more effective option.

Appetite suppressants can cause side effects, like all medications.

The most commonly reported side effects of appetite suppressants include constipation or diarrhoea, feeling or being sick (nausea and vomiting), and digestive issues.

Here is an overview of the most common side effects of the main prescription appetite suppressants available in the UK:

Over-the-counter appetite suppressants and supplements can also cause side effects.

For example:

Glucomannan is very high in fibre and can have uncomfortable side effects such as:

• bloating
• stomach pain
• constipation
• gas
• diarrhoea

Caffeine-based supplements may cause:

• difficulty sleeping
• jitteriness and anxiety

Serious side effects

When taking any medication or supplement, you need to be aware of the signs of serious side effects that may need medical attention such as

an allergic reaction (anaphylaxis). This includes:

• breathing difficulties (breathlessness or wheezing)
• swelling of the mouth, throat, tongue, face or lips
• a fast heartbeat

Pancreatitis with weight loss injections (Mounjaro, Wegovy, and Nevolat) could be a rare but serious side effect. Its symptoms include:

• severe pain in the abdomen (stomach area) that does not go away
• nausea and vomiting

With Mysimba, a rare but serious side effect is feeling suicidal or depressed.

Appetite suppressants are not suitable for everyone, they are designed for people who are overweight or obese. Prescription appetite suppressants are only available to people in the UK if they have either:

1. A BMI of 30 or more.
2. A BMI of 27 or more and a health condition related to their weight such as type 2 diabetes or hypertension.

➤ Your BMI is a way to measure if you are overweight or obese. It is calculated using your height and weight. You can calculate your BMI with ZAVA’s BMI calculator.

If you think that appetite suppressants may be suitable for you, start a consultation with one of our online doctors today.

• Is reduction in appetite beneficial for body weight management in the context of overweight and obesity? Yes, according to the SATIN (Satiety Innovation) study, National Library of Medicine [Accessed 9 February 2025]
• The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials, National Library of Medicine [Accessed 10 February 2025]
• Acute epigallocatechin 3 gallate (egcg) supplementation delays gastric emptying in healthy women: A randomized, double-blind, placebo-controlled crossover study, National Library of Medicine [Accessed 11 February 2025]
• Appetite-Suppressing and Satiety-Increasing Bioactive Phytochemicals: A Systematic Review, National Library of Medicine [Accessed 11 February 2025]
• Mysimba 8 mg/90 mg prolonged-release tablets, emc [accessed 11 February 2025]
• Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen, emc [accessed 11 February 2025]
• Wegovy 2.4 mg, FlexTouch solution for injection in pre-filled pen, emc [accessed 11 February 2025]
• Nevolat 6 mg/ml solution for injection in pre-filled pen, emc [accessed 11 February 2025]
• [Glucomannan: properties and therapeutic applications], National Library of Medicine [accessed 18 February 2025]