Phentermine and Dry Mouth

Phentermine and Dry Mouth

Dry mouth, medically referred to as xerostomia, is the number one phentermine side effect. Weight loss medications like phentermine promote this feeling of dryness in the mouth, lips, and tongue due to their stimulant effect.

Thankfully, most patients report that phentermine dry mouth is only temporary and noticeably improves as treatment progresses.

Does Phentermine Cause Dry Mouth?

Yes, dry mouth is the most common side effect of phentermine weight loss pills ( 1 ).

According to a recent online poll, 4 out of 5 phentermine users experience dry mouth. In fact, dry mouth is a shocking 30% more common than the next most-reported side effect: insomnia.

Poll Results (graph): Top 10 Phentermine Side Effects
Results of a 2019 poll on users’ most common phentermine side effects

Phentermine Tongue Side Effects

Phentermine does not have any tongue-specific side effects listed on the box, but they can (and do) sometimes occur secondary to phentermine dry mouth.

Patients with dry mouth are at increased risk for oral yeast infections. Also known as thrush or candidiasis, these infections typically present as a white, clumpy plaque, but may also appear red and irritated. Pain or change in taste is possible but rare ( 2 ).

If you think you have thrush or other phentermine tongue side effects, speak with your dentist and prescribing doctor.

Phentermine and Dry Mouth

Woman with phentermine dry mouth
Dry mouth is the most common side effect of phentermine

When you take a stimulant like phentermine, epinephrine, and norepinephrine levels spike to increase energy. These neurotransmitters also signal the body to divert resources away from non-critical bodily functions like hunger cues and digestion.

So, phentermine causes dry mouth because when the brain sends out a signal to divert resources away from digestion, saliva production in the mouth decreases ( 3 ). With less saliva, the mouth and tongue quickly grow dry and uncomfortable.

Interestingly, this is the same reason your mouth and lips feel dry when you’re nervous or scared.

Does dry mouth from phentermine go away?

The severity of xerostomia varies from person to person, but most patients report improvement in symptoms after 1-2 weeks of treatment. Staying properly hydrated can also help alleviate some of the most bothersome symptoms.

Dry Mouth and Bad Breath

Unfortunately, phentermine dry mouth and bad breath often occur together.

The dry oral environment serves as a perfect breeding ground for bacteria, some of which cause bad breath. Due to dryness of the surrounding tissues, some people also experience phentermine dry mouth and sore throat together.

How to Get Rid of Dry Mouth from Phentermine

Thirst is not the only thing that makes your mouth feel dry and uncomfortable while taking phentermine: this cotton-mouth feeling is also a common side effect of stimulants.

So, many patients wonder how to get rid of dry mouth from phentermine. The American Academy of Oral Medicine offers the following remedies ( 4 ):

Woman drinking water to cope with phentermine dry mouth
Drinking water can help alleviate phentermine dry mouth

1. Drink Water

Phentermine produces both extreme thirst and an uncomfortable dry mouth, so it’s important to drink plenty of water. Take frequent sips of water or munch on ice throughout the day to keep tissues moisturized.

Hydration also helps suppress hunger, support healthy metabolism and decrease bloating. Carry a bottle of water with you at all times to help you stay hydrated.

2. Pack Sugar-Free Gum & Mints

Chewing gum or sucking on candy and mints encourages the production of additional saliva, which can help alleviate dry mouth.

Plus, since bad breath occurs alongside dry mouth, peppermint, or other breath-freshening gum or mints tackle two problems at once by decreasing dryness and improving breath. Just make sure to opt for sugar-free options to minimize extra calories and mitigate cavity risk.

3. Maintain Good Oral Health

Regular checks at the dentist and daily brushing, flossing, and rinsing ensure help maintain good oral health.

If you experience prolonged periods of dryness, pay extra attention to your oral health and see your dentist regularly since dental problems like cavities and sores worsen faster if your mouth is dry.

4. Use a Humidifier

A humidifier adds moisture to the air, which can be an effective phentermine dry mouth treatment – especially if you live in a dry climate, use central heating, or have chronic respiratory issues. Place a humidifier in your bedroom to help alleviate dry mouth symptoms while you sleep.

5. Eat Foods with High Water Content

Sometimes it’s hard to drink enough water throughout the day. Thankfully, not all hydration needs to come in liquid form.

Eating foods with a high water content can also help. Fresh fruits (e.g. watermelon, strawberries, melon and grapefruit), vegetables (e.g. cucumber, celery, lettuce and peppers) and soup are all great options to boost hydration and combat dry mouth at mealtime ( 5 ).

Caffeinated and sweet drinks that worsen phentermine dry mouth
Soda can make phentermine dry mouth worse

6. Minimize Caffeinated and Sweet Drinks

Doctors often recommend that patients steer clear of caffeine while taking phentermine due to the medication’s already-strong stimulant effects.

Another reason to skip the morning cup of coffee? Caffeine is a diuretic, meaning that it increases fluid loss. While the occasional coffee, tea, or cola can help contribute to your fluid overall intake, it’s unwise to rely on caffeinated drinks as your primary source of hydration.

Likewise, sugary drinks provide extra, unnecessary calories that can slow weight loss and contribute to dental decay. Given that dry mouth speeds up dental decay, this is just another reason to choose sugar-free options during your weight loss journey with phentermine.

Instead, stay hydrated with caffeine-free, sugar-free options like water or herbal tea.

7. Invest in Lip Balm

Chapped lips are one of the most annoying symptoms of chronic dry mouth. So, keep an oil-based balm on hand to soothe dry lips.

8. Use a Saliva Substitute

If at-home phentermine dry mouth remedies are not working, consider using an over-the-counter liquid or gel. These products’ effects are temporary but may provide some short-term relief.

Back to All Phentermine Side Effects

  1. Cosentino, G., Conrad, A., & Uwaifo, G. (2011). Phentermine and topiramate for the management of obesity: A review. Drug Design, Development and Therapy, 267. doi:10.2147/dddt.s31443
  2. Redding, S., & AAOM Web Writing Group. (2015, October 21). Oral Yeast Infections.
  3. Miranda-Rius, J., Brunet-Llobet, L., Lahor-Soler, E., & Farré, M. (2015). Salivary Secretory Disorders, Inducing Drugs, and Clinical Management. International Journal of Medical Sciences, 12(10), 811-824. doi:10.7150/ijms.12912
  4. Sankar, V., Rhodus, N., & AAOM Web Writing Group. (2015, October 15). Dry Mouth.
  5. (2014, March 25). Eating When You’re Dehydrated.