Weight-Loss Injections and Oral Health

4th August 2026

Weight-loss injections have become one of the most talked-about health developments of recent years. Medicines such as Wegovy and Mounjaro are now being used by a growing number of people, while similar medicines are prescribed to manage type 2 diabetes.

These treatments do not automatically damage your teeth. However, some of their possible side effects can indirectly affect your mouth, particularly if you experience dehydration, nausea, vomiting or acid reflux.

Here is what you need to know and how you can protect your smile while using these medicines.

What are GLP-1 medicines?

GLP-1 and related medicines work by affecting appetite, blood sugar and the speed at which food leaves the stomach. Some are licensed for weight management, while others are primarily used to treat type 2 diabetes.

In January 2026, the Medicines and Healthcare products Regulatory Agency reported that an estimated 1.6 million adults in England, Wales and Scotland had used medicines such as semaglutide and tirzepatide to lose weight between early 2024 and early 2025.

Most people use these medicines without developing serious problems. However, the MHRA advises that common side effects can include nausea, vomiting and diarrhoea. These symptoms can sometimes result in dehydration.

For your teeth and gums, it is generally these indirect effects that matter.

Dry mouth and dehydration

Saliva does far more than keep your mouth feeling comfortable. It helps wash away food particles, neutralise acids and protect your teeth against decay.

If you become dehydrated because you are vomiting, have diarrhoea or simply find it difficult to drink enough, your mouth may feel unusually dry. A reduced flow of saliva can contribute to:

Bad breath
Increased plaque
A higher risk of tooth decay
Sore or cracked lips
Difficulty swallowing dry foods
A sticky or uncomfortable feeling in the mouth

The Oral Health Foundation describes saliva as one of the mouth’s natural defences against decay, making good hydration particularly important.

Sip plain water regularly throughout the day. Sugar-free chewing gum can also help stimulate saliva, provided it is suitable for you. If your mouth remains persistently dry, tell your dentist, as additional protective treatment may be recommended.

Vomiting, reflux and tooth erosion

Vomiting and acid reflux bring stomach acid into contact with the teeth. This can soften and gradually wear away the enamel, the hard protective surface covering each tooth.

Repeated exposure can lead to dental erosion, which may cause:

Increased sensitivity
Teeth appearing more yellow
Thinner or more transparent tooth edges
Small chips or changes to the tooth shape
Discomfort when eating hot, cold or acidic foods

One isolated episode of sickness is unlikely to cause noticeable damage. The greater concern is frequent vomiting or reflux over an extended period.

If you have been sick, resist the urge to brush your teeth immediately. Brushing while the enamel is temporarily softened can remove more of its surface.

Instead, rinse your mouth gently with water and wait for around an hour before brushing. The Oral Health Foundation’s dental erosion guidance explains that this allows saliva time to neutralise the acid and help the enamel recover.

If sickness or reflux continues, speak to the healthcare professional who prescribed your medicine.

Be careful how you manage nausea

People experiencing nausea sometimes start sipping fizzy drinks, fruit juice or sweetened tea throughout the day. Others suck sweets or graze frequently because they find small snacks easier to tolerate.

Although this may help settle your stomach, regularly exposing the teeth to sugar or acid increases the opportunities for decay and erosion to develop.

Try to make plain water your usual drink. Where possible, keep sugary or acidic foods and drinks to mealtimes rather than consuming them repeatedly throughout the day.

Your wider health must come first, particularly if you have diabetes or have been given specific dietary advice. If you regularly need sugary foods or drinks to manage low blood sugar, discuss this with your dental team so they can recommend additional protection for your teeth.

How to protect your teeth

A few practical habits can reduce the likelihood of dental problems:

Drink water regularly. This helps prevent dehydration and supports a healthy flow of saliva.
Brush twice a day with fluoride toothpaste. Adults should normally use toothpaste containing between 1,350 and 1,500 parts per million fluoride.
Spit rather than rinse after brushing. This leaves fluoride on the teeth for longer.
Clean between your teeth daily. Use floss or interdental brushes in the size recommended by your dental team.
Wait before brushing after vomiting or reflux. Rinse with water and allow approximately one hour before brushing.
Choose sugar-free gum. Chewing gum can encourage saliva production and help your mouth recover after eating.
Attend regular dental examinations. Early enamel erosion and decay are much easier to manage before they become painful.

Your dentist may recommend additional fluoride products if dry mouth, vomiting or reflux places you at a higher risk of decay.

Tell your dentist what you are taking

Always keep your dental team informed about your medicines, including injections obtained through a private prescriber or online pharmacy. This information is confidential and helps us plan your care safely.

GLP-1 and related medicines can slow the emptying of the stomach. This is especially relevant if you are referred for treatment involving deep sedation or a general anaesthetic. The Royal College of Anaesthetists advises patients to tell their healthcare team before such procedures.

Do not stop taking prescribed medicine before dental treatment unless your doctor, prescriber or anaesthetist specifically advises you to do so.

When should you seek advice?

Contact your dentist if you develop persistent dry mouth, new sensitivity, changes to the appearance of your teeth or discomfort when eating and drinking.

You should also speak to your GP or prescribing clinician if nausea, vomiting, diarrhoea or reflux is persistent or difficult to manage.

The MHRA advises anyone taking these medicines to seek urgent medical help for severe and persistent stomach pain that may spread to the back, particularly if it is accompanied by nausea or vomiting, as this can be a symptom of pancreatitis.