Sounds, light and substances

Sound cues during sleep: a study with a phone app found more lucid dreams, but couldn’t rule out an expectation effect. In the lab, cues were not clearly better than practice alone and woke participants in about one out of four phases.

Light masks: early small studies were positive, newer ones were not. Many devices don’t reliably detect dream sleep.

Substances: in one study, a dementia medication triggered more lucid dreams. It requires a prescription and has side effects. Finally Lucid does not recommend any medication or supplements.