Galantamine

Galantamine is an alkaloid from the snowdrop (Galanthus), the red spider lily (Lycoris radiata) and daffodil bulbs, licensed as a treatment for mild-to-moderate Alzheimer's disease. In the dream literature it is the best-studied pharmacological lucid-dream aid, and it is the one entry in that materials list with a controlled trial behind it.

Mechanism

Two actions:

Acetylcholinesterase inhibition — raises synaptic acetylcholine.
Allosteric potentiation of nicotinic receptors — a second, less common mechanism that distinguishes it from donepezil and rivastigmine.

REM sleep is a cholinergically driven state. Raising acetylcholine during the REM-dense second half of the night lengthens and intensifies REM, and increases the probability of the reflective awareness that defines a lucid dream.

The evidence

LaBerge et al. (2018), a double-blind placebo-controlled crossover trial in 121 participants at a dream retreat, is the study this rests on. Galantamine taken after 4.5 hours of sleep — the WBTB position — produced lucid dreams in a dose-dependent fashion, with the higher dose producing a substantially higher rate than placebo, and the effect was strongest when combined with the MILD induction technique.

This is unusual: a supplement claim with a real randomised trial, a dose-response and an interaction with a behavioural technique. It is also one trial, in a self-selected population already practised at lucid dreaming.

Timing is the whole technique

Galantamine taken at bedtime does not work well and disrupts sleep. It is taken on waking after 4–5 hours, then sleep is resumed — the WBTB ("wake back to bed") position. Its ~7-hour half-life then covers the REM-dense final stretch.

It is conventionally paired with a choline donor (alpha-GPC or citicoline) on the reasoning that inhibiting the esterase is of limited use without substrate.

Cautions — this is a real drug

Galantamine is a prescription medicine in most jurisdictions, sold as a supplement in the United States because of its plant origin. The cautions are the clinical ones:

Bradycardia, heart block, syncope. Cholinesterase inhibitors slow the heart. Relevant in existing conduction disease and with beta-blockers or other rate-limiting drugs.
Asthma and COPD — cholinergic bronchoconstriction.
Peptic ulcer and GI bleeding risk — increased gastric acid; interacts with NSAID use.
Seizure threshold is lowered.
Urinary obstruction and bladder outflow disease.
Do not combine with other cholinesterase inhibitors, and note the direct antagonism with anticholinergics — including Datura, which appears in the same historical dream literature and is its pharmacological opposite.
Sleep disruption, vivid nightmares and next-day nausea are the common complaints even when it works.
Frequency matters: tolerance develops, and it is conventionally used no more than once or twice a week.

See also: Choline Donors · Datura · Racetams · Stack Substances