Mouth tape (taping your mouth shut to force nasal breathing during sleep) hasn't been shown to stop you 'breathing in nasty stuff' while you sleep — and it carries a real risk if your nose is blocked or if you have undiagnosed sleep apnea.

noli's read

The most recent systematic review on this (PLOS ONE, 2025, 10 studies, 213 patients total) notes that every included study was rated poor methodological quality (Newcastle-Ottawa scale), and only 2 of the 10 studies showed a statistically significant improvement in the apnea-hypopnea index — and only in mild-apnea subgroups — with most others finding no difference. Nothing in this literature tests or confirms the post's specific claim ('breathing in nasty stuff' while sleeping mouth-open) — that's a fear-based line that sells the product more than it describes evidence. The more serious point is safety: 4 of the 10 studies in the review explicitly flag asphyxiation risk with nasal obstruction, and no official sleep-society guideline was found endorsing this practice for the general population — per Cleveland Clinic and CNN coverage, it remains a clinically unvalidated social-media trend, dangerous in particular for anyone with undiagnosed sleep apnea or a congested nose. Verdict: unproven for the claim itself, with a genuine safety caution that shouldn't be minimized.

the sources

1. 1Senaratna CV, Perret JL, Lodge CJ, et al. 2016
2. 2Wang X, Ouyang Y, Wang Z, et al. 2013
3. 3Kaditis AG, Alonso Alvarez ML, Boudewyns A, et al. 2016