Condition
Dry Mouth
No pill or supplement taken by mouth has good evidence for dry mouth (xerostomia). The studies on file tested betaine in toothpaste, mouthwash and gels, not betaine capsules. Our database grades those mouth products B (moderate) for saliva flow, from 3 small, short trials with 143 people, and one tested a mix with olive oil and xylitol. A Cochrane review of 36 trials found no strong evidence that any mouth product works. Medicines are a common cause, especially bladder drugs and antidepressants, so ask your prescriber before changing one. Dry eyes plus dry mouth can point to Sjögren's syndrome and needs a doctor's visit.
Sources: PMID 9669455; PMID 17824884; PMID 21950587; PMID 22161442; PMID 29071719; PMID 28610655
- Supplements studied
- 1
- Graded outcomes
- 2
- Trials
- 4
- People studied
- 188
What the evidence says
- Betaine toothpaste: limited evidence. In a 2-week crossover trial of 13 people with chronic dry mouth, a toothpaste with 4% betaine relieved several dry-mouth symptoms compared with the same paste without it. In a 6-week crossover trial with 27 people who had dry mouth and 18 who did not, the betaine paste relieved symptoms in 44% of those with dry mouth, against 7% with a plain reference paste.
- Betaine mixes and mouthwash: limited evidence. A set of mouth products with olive oil, betaine and xylitol raised resting saliva flow and eased complaints over 1 week in 40 adults whose dry mouth came from taking many medicines. In an unblinded 4-week trial that 90 people finished, a betaine mouthwash, a night mouth guard and both together all eased symptoms, with no difference in satisfaction between them.
- Not in our database yet: a 1% malic acid mouth spray eased dry-mouth symptoms and raised saliva flow more than a placebo spray over 2 weeks, in 5 trials with 244 people. The reviewers called the studies limited.
- Across mouth products as a group, a Cochrane review of 36 randomized trials with 1,597 people found no strong evidence that any spray, gel, lozenge, gum or toothpaste relieves dry mouth. Chewing gum raised saliva in people who still make some, but was no better or worse than saliva substitutes.
- Omega-3 and vitamin E appear in the Dry Mouth protocol, but the evidence is thin: in a trial of 61 people with Sjögren's syndrome, an omega-3 supplement did not raise saliva flow more than wheat germ oil.
Safety and when to see a clinician
- Medicines are a leading cause. In a review of 52 studies in people aged 60 and over, bladder (urinary incontinence) drugs, antidepressants and sedative-type drugs were most strongly linked to dry mouth, and the risk rose with the number of medicines taken. Don't stop a prescribed medicine on your own; ask the prescriber or a pharmacist about alternatives.
- Dry eyes together with dry mouth are the leading signs of Sjögren's syndrome, an autoimmune disease that also raises the risk of lymphoma, so that pairing needs a doctor's assessment.
- Betaine HCl capsules are not the product these trials tested; every betaine study on file used a toothpaste, mouthwash or other mouth product.
- See a dentist or doctor if dry mouth lasts more than a few weeks, started after radiation to the head or neck, or comes with trouble swallowing, mouth sores or new tooth decay.
Evidence by supplement
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Salivation Small Increase | Improves (the measure goes up) | Small effect | 3 studies | 143 people | ||
Studies that measured salivation
| ||||||
| Dry Mouth Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 1 study | 45 people | ||
Studies that measured dry mouth symptoms | ||||||
Key findings
- SalivationImproves (the measure goes up)
- Dry Mouth SymptomsImproves (the measure goes down)
The Dry Mouth (Xerostomia) Management protocol
2 primary supplements · 6 supporting supplements
- Omega-3 Fatty Acids1–2 g EPA+DHA daily
- Vitamin E400 IU oral daily; topical application as needed
Studies cited
9 studies from PubMed
- Effects of a betaine-containing toothpaste on subjective symptoms of dry mouth: a randomized clinical trial.
- Betaine-containing toothpaste relieves subjective symptoms of dry mouth.
- Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy-induced dry mouth.
- Evaluation of the clinical efficacy of a betaine-containing mouthwash and an intraoral device for the treatment of dry mouth.
- Efficacy of a 1% malic acid spray for xerostomia treatment: A systematic review and meta-analysis.
- Interventions for the management of dry mouth: topical therapies.
- Effect of omega-3 and vitamin E supplementation on dry mouth in patients with Sjögren's syndrome.
- Medications That Cause Dry Mouth As an Adverse Effect in Older People: A Systematic Review and Metaanalysis.
- The Diagnosis and Treatment of Sjögren's Syndrome.