Dry mouth

Dry mouth is a reduction in saliva production felt as a parched, tacky sensation inside the mouth and throat.

As a drug effect it is acute and dose-proportional, easing as the substance wears off, which distinguishes it from chronic xerostomia arising from medical conditions. It ranges from a mild thickening of saliva to a pronounced dryness that makes swallowing and speech uncomfortable.

Dry mouth is among the most commonly reported physical effects across psychoactive substances. It is most commonly induced at moderate to high doses under stimulants such as amphetamine, MDMA, and 6-APB, and under cannabinoids such as cannabis, AB-FUBINACA, and APICA. It also appears under psychedelics such as LSD, psilocybin mushrooms, and 25B-NBOH, and under depressants including alprazolam, clonidine, and flunitrazepam.

Dry mouth is felt as a persistent dryness that begins at the lips and spreads inward — saliva thickens or disappears, the tongue drags against the palate, and the throat feels coated. Speaking becomes effortful, swallowing requires deliberate intent.

Thirst is often present, but drinking brings only brief relief, since the underlying suppression of salivation continues throughout the experience. At higher doses, particularly under stimulants and cannabinoids, the sensation becomes pronounced enough that attention is drawn toward it repeatedly, amplifying what would otherwise be a background discomfort.

Dry mouth arises through different pathways depending on the drug class:

• Stimulants — activate the sympathetic nervous system, suppressing the parasympathetic drive that sustains salivary secretion.
• Cannabinoids — act on CB1 receptors present in the salivary glands, directly inhibiting saliva production.
• Psychedelics — reduce secretomotor activity through serotonergic or mild anticholinergic effects, though the exact pathway varies by compound.
• Depressants — reduce autonomic tone broadly; some, such as clonidine, act centrally to suppress salivary output.

How much each pathway contributes in a given case is not fully understood.

Who experiences it, and how strongly, varies widely. Higher doses reliably intensify it across all classes. Ambient heat and physical activity compound the effect — especially under stimulants — by layering ordinary dehydration on top of suppressed salivation.

Individual differences in baseline salivary flow and autonomic reactivity shape baseline severity, as does prior hydration. Expectation plays a smaller role here than in affective effects. Drinking water before and during a session provides modest but consistent relief and remains the most reliably protective factor.