Cannabidiol (CBD) is a compound found in the cannabis plant known for its potential benefits. Users frequently report dry mouth, medically termed xerostomia, as a common side effect. This occurs because CBD interacts with the body’s biological systems that regulate saliva production. This article explores the biological reasons behind CBD-induced dry mouth and offers practical advice for managing it.
Defining Xerostomia and Saliva Production
The sensation of dry mouth, or xerostomia, results from a decrease in the amount or quality of saliva produced in the mouth. Common symptoms include a sticky, dry feeling, difficulty swallowing, a sore throat, and a changed sense of taste. When severe or chronic, this lack of moisture can also contribute to bad breath, lip sores, and an increased risk of dental problems.
Saliva aids in the initial stages of digestion and helps lubricate food for easier swallowing and speaking. Saliva also protects oral tissues, neutralizes acids, and contains compounds that help fight against bacteria, which is why a reduction in flow can compromise oral health.
This fluid is primarily produced by three pairs of major salivary glands: the parotid, the submandibular, and the sublingual glands. The submandibular glands, located under the jaw, are responsible for secreting a significant portion of the total saliva volume. The entire process of saliva secretion is tightly regulated by the nervous system, specifically the parasympathetic branch, which signals the glands to begin production.
The Specific Interaction: CBD and Salivary Gland Receptors
The reason CBD can lead to dry mouth is rooted in its interaction with the body’s Endocannabinoid System (ECS). The ECS includes cannabinoid receptors, which are found throughout the body, including within the salivary glands.
Research has identified the presence of both cannabinoid receptor type 1 (CB1) and type 2 (CB2) in the major salivary glands, particularly in the submandibular glands. These receptors are not located on the saliva-producing cells themselves but on the nerve endings that innervate the glands. Specifically, the CB1 receptors are expressed on the axons of cholinergic neurons, which are the nerve fibers responsible for stimulating saliva production.
Saliva secretion is normally triggered when the parasympathetic nervous system releases a neurotransmitter called acetylcholine onto the gland cells. Acetylcholine acts as the signal to initiate the flow of saliva. When CB1 receptors are activated by cannabinoids, they inhibit the release of this acetylcholine. This interference effectively suppresses the normal signaling cascade that tells the salivary glands to produce and secrete saliva.
While CBD is not a strong direct activator of CB1 receptors like its relative THC, it can still modulate the ECS in ways that lead to a reduction in saliva. One proposed mechanism involves CBD increasing the concentration of anandamide, a naturally occurring endocannabinoid. Anandamide has a high affinity for CB1 receptors and can inhibit saliva secretion, meaning CBD can indirectly lead to the same result by slowing the breakdown of this natural compound.
This action is a local effect, meaning the suppression of saliva production occurs directly at the gland level. The presence of CB2 receptors and other targets like the transient receptor potential vanilloid type 1 (TRPV1) may also play a role, but the primary scientific focus remains on the CB1 receptor’s inhibitory effect on cholinergic signaling. The severity of this dryness can often be influenced by the dosage and the method of consumption, with sublingual products potentially causing a more immediate, localized effect.
Practical Steps for Relieving Dry Mouth
Managing CBD-induced dry mouth focuses on stimulating saliva flow and maintaining oral moisture. The simplest and most effective strategy is to stay consistently hydrated by drinking plenty of water throughout the day. Sipping water frequently, especially during and after consuming CBD, helps to lubricate the mouth.
Chewing sugar-free gum or sucking on sugar-free candies or lozenges can help stimulate the salivary glands to increase production. Products containing xylitol are particularly beneficial, as this ingredient can also help reduce oral bacteria. Using over-the-counter saliva substitutes, which come in sprays, gels, or lozenges, can provide temporary relief by coating the oral tissues with an artificial moisture film.
It is also advisable to avoid substances that can further exacerbate oral dryness. This includes beverages containing caffeine, alcohol, and tobacco products, all of which have dehydrating or astringent properties. Choosing water-rich foods and maintaining excellent oral hygiene, such as brushing twice daily with fluoride toothpaste, are important steps to protect teeth and gums when saliva flow is reduced. If the dry mouth persists or becomes a significant issue, consulting with a healthcare provider about adjusting the CBD dosage or considering alternative consumption methods may be necessary.