Patients using GLP-1 drugs are reporting a complication not listed among the drug’s most common side effects, according to some experts, with dentists warning they’re seeing cases of something nicknamed “Ozempic teeth” – dry mouth, halitosis and furry tongues, and even tooth decay.
The dry mouth happens because the active ingredient, semaglutide, affects the salivary glands, according to Adam Taylor, an anatomy professor at Britain’s Lancaster University, in The Conversation.
He writes that it does this by reducing saliva production (hyposalivation), leading in turn to dry mouth (xerostomia) because there isn’t enough saliva to keep the mouth wet.
It isn’t exactly clear why semaglutide has this effect on the salivary glands. But in animal studies of the drug, it appears the drug makes saliva stickier. This means there’s less fluid to moisten the mouth, causing it to dry out.
GLP-1 receptor agonist drugs (like semaglutide) can also reduce water intake by affecting areas in the brain responsible for thirst. Low fluid intake further reduces saliva production, and may cause the saliva to become thick and frothy and the tongue to become sticky.
Bad breath
One other commonly reported unwanted effect by semaglutide users is bad breath (halitosis).
When there’s less saliva flowing through the mouth, this encourages bacteria that contribute to bad breath and the formation of cavities to thrive. These bacterial species include Streptococcus mutans and some strains of Lactobacillus.
Another species that has been shown to thrive in conditions where saliva is reduced is Porphyromonas gingivalis. This bacteria is a significant contributor to the production of volatile sulphur compounds, which cause the foul odours characteristic of halitosis.
Another factor that might explain why semaglutide causes bad breath is because less saliva being produced means the tongue isn’t cleaned. This is the same reason why people’s “morning breath” is so bad, because we naturally produce less saliva at night.
This allows bacteria to grow and produce odours. Case report images show some people taking semaglutide have a “furry”-like or coated appearance to their tongue. This indicates a build up of bacteria that contribute to bad breath.
Tooth damage
One of the major side effects of Ozempic is vomiting. Semaglutide slows the speed at which the stomach empties, delaying digestion, which can lead to bloating, nausea and vomiting.
But repeated vomiting can damage the teeth. This is because stomach acid, composed primarily of hydrochloric acid, erodes the tooth enamel. Where vomiting occurs over a prolonged period of months and years, the more damage will occur.
The back surface of the teeth (palatal surface) closest to the tongue is more likely to see damage – which may not be obvious to the sufferer.
Vomiting also reduces the amount of fluid in the body. When combined with reduced saliva production, this puts the teeth at even greater risk of damage. This is because saliva helps neutralise the acid that causes dental damage.
Saliva also contributes to the dental pellicle – a thin, protective layer that the saliva forms on the surface of the teeth. It’s thickest on the tongue-facing surface of the bottom row of teeth. In people who produce less saliva, the dental pellicle contains fewer mucins, a type of mucus which helps saliva stick to the teeth.
Reducing risk
Physicians should warn patients taking semaglutide of what they can do to keep their mouths healthy.
Drinking water regularly during the day can help to keep the oral surfaces from drying out, and maintain the natural oral microbiome, which can reduce the risk of an overgrowth of the bacteria that cause bad breath and tooth damage.
Drinking plenty of water also enables the body to produce the saliva needed to prevent dry mouth, ideally the recommended daily amount of six to eight glasses.
Chewing sugar-free gum is also a sensible option as it helps to encourage saliva production. Swallowing this saliva keeps the valuable fluid within the body. Gums containing eucalyptus may help to prevent halitosis, too.
There’s some evidence that probiotics may help to alleviate bad breath, at least in the short term. Using a probiotic supplements or consuming probiotic-rich foods (such as yoghurt or kefir) may be a good idea.
Women are twice as likely to have side-effects when taking GLP-1 receptor agonists – including gastrointestinal symptoms like vomiting. This may be due to the sex hormones oestrogen and progesterone, which can alter the gut’s sensitivity.
It isn’t clear how long these side effects last, and they are likely to disappear when the medication is stopped, but any damage to the teeth is permanent.
Gastrointestinal side effects can last a few weeks but usually resolve on their own unless a higher dose is taken.
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